OCS Study

BOEM 2018-024

US Department of the Interior

Bureau of Ocean Energy Management

Alaska Region

Marine Arctic Ecosystem Study—

Biophysical and Chemical Observations 

From Glider and Benthic Surveys in 

2016
OCS Study

BOEM 2018-024

US Department of the Interior

Bureau of Ocean Energy Management

Alaska Region

Marine Arctic Ecosystem Study—

Biophysical and Chemical Observations 

From Glider and Benthic Surveys in 

2016

April 2018

Authors:

Francis K. Wiese – MARES Technical Director (Stantec)

H. Rodger Harvey – Biogeochemistry Lead (ODU)

Rachel McMahon – Biogeochemistry Team (ODU)

Pam Neubert – Benthic Taxanomy Lead (Stantec)

Donglai Gong – Glider Lead (VIMS)

Haixing Wang – Glider Team (VIMS)

Jeanna Hudson – Glider Team (VIMS)

Robert Pickard – Moorings Lead (WHOI)

Ed Ross – Moorings Lead (ASL)

Matt Charette – Nutrient Analysis Lead (WHOI)

Michael Fabijan – Consultations and Permitting Lead (Kavik-Stantec)

Rowenna D. Gryba – MARES Task Order Manager (Stantec)

Prepared under BOEM Award

M14PC00008 – Task Order No. M15PD00012

By

Stantec Consulting Services Inc.

4500 Daley Dr., Suite 100

Chantilly, VA 20151-3724
DISCLAIMER

Study concept, oversight, and funding were provided by the US Department of the Interior, Bureau of 

Ocean Energy Management (BOEM), Environmental Studies Program, Washington, DC, under Contract 

Number M14PC00008. This report has been technically reviewed by BOEM, and it has been approved 

for publication. The views and conclusions contained in this document are those of the authors and should 

not be interpreted as representing the opinions or policies of the US Government, nor does mention of 

trade names or commercial products constitute endorsement or recommendation for use.

REPORT AVAILABILITY

To download a PDF file of this report, go to the US Department of the Interior, Bureau of Ocean Energy 

Management Data and Information Systems webpage (http://www.boem.gov/Environmental-StudiesEnvData/), click on the link for the Environmental Studies Program Information System (ESPIS), and 

search on 2018-024. The report is also available at the National Technical Reports Library at 

https://ntrl.ntis.gov/NTRL/.

CITATION

Wiese FK, Harvey HR, McMahon R, Neubert P, Gong D, Wang H, Hudson J, Pickard R, Ross E, Fabijan 

M, Gryba RD. 2018. Marine Arctic Ecosystem Study—Biophysical and chemical observations from 

glider and benthic surveys in 2016. Anchorage (AK): US Department of the Interior, Bureau of Ocean 

Energy Management. OCS Study BOEM 2018-024. 98 p.

ABOUT THE COVER

Photo Credit: J. Bartlett, ASL 

ACKNOWLEDGMENTS

We would like to acknowledge the support provided by the Stantec MARES team: Diane Ingraham, Jeff 

Green, Cathy Finnie, Barry Keough, Melissa Gandy and Ally Sullivan. We would like to also 

acknowledge COR, Guillermo Auad, and the contributions of John Nelson, Dave Fissel, and Carin 

Ashjian on the mooring array design and location. 
i

Contents

List of Figures................................................................................................................................................iii

List of Tables................................................................................................................................................. v

List of Abbreviations and Acronyms............................................................................................................. vi

1 Overview ............................................................................................................................................... 1

1.1 Background ................................................................................................................................... 1

1.2 Biophysical and Chemical Program Goals and Objectives...........................................................1

1.3 Study Design and Implementation ................................................................................................ 1

1.3.1 Study Design......................................................................................................................... 1

1.3.2 Implementation 2015............................................................................................................. 2

1.3.3 Implementation 2016............................................................................................................. 2

1.4 Community Consultations ............................................................................................................. 3

1.5 Permitting ...................................................................................................................................... 3

2 AUV Glider Component ........................................................................................................................ 4

2.1 Introduction.................................................................................................................................... 4

2.2 Methods......................................................................................................................................... 4

2.2.1 Glider Setup and Sensor Suite.............................................................................................. 4

2.2.2 Glider Preparation for 2016................................................................................................... 5

2.2.3 2016 Glider Survey Plan ....................................................................................................... 5

2.2.4 Glider Deployment................................................................................................................. 6

2.2.5 Piloting................................................................................................................................... 7

2.2.6 Glider Recovery..................................................................................................................... 7

2.2.7 MARES Glider Data Management and QA/QC ....................................................................7

2.2.8 Ocean Data and Ocean Model Output Used for Analysis ....................................................8

2.3 Results .......................................................................................................................................... 9

2.3.1 Characterization of the Physical Oceanographic Setting......................................................9

2.3.2 Hydrography & Water Masses ............................................................................................13

2.3.3 Circulation Based on Glider Observations ..........................................................................16

2.3.4 Characterization of the Bio-Optical Conditions ...................................................................16

2.3.5 Variability of Hydrography and Circulation..........................................................................18

2.3.6 Wind-Driven Circulation ......................................................................................................22

2.4 Discussion...................................................................................................................................28

2.4.1 Connection Between Beaufort Shelf and Beaufort Gyre ....................................................29

2.4.2 Multi-Year Variability of Zonal Winds in the Beaufort Sea ..................................................29
ii

2.4.3 Fate of the Mackenzie Plume..............................................................................................30

2.5 Conclusions.................................................................................................................................30

2.6 Limitations of the MARES Glider Survey ....................................................................................31

2.7 Future Research .........................................................................................................................31

3 Mooring Array......................................................................................................................................33

3.1 Introduction..................................................................................................................................33

3.2 Methods.......................................................................................................................................33

3.2.1 Field Methods and Equipment ............................................................................................33

3.3 Results and Conclusions.............................................................................................................39

4 Linking Organic Carbon Sources with Meiofauna Abundance and Diversity .....................................43

4.1 Introduction..................................................................................................................................43

4.2 Methods.......................................................................................................................................43

4.2.1 Sampling Locations.............................................................................................................43

4.2.2 Water Column Particles ......................................................................................................44

4.2.3 Sediments ...........................................................................................................................44

4.2.4 Total Organic Carbon..........................................................................................................45

4.2.5 Grain Size............................................................................................................................45

4.2.6 Meiofaunal Abundance and Diversity .................................................................................45

4.2.7 Organic Biomarkers.............................................................................................................45

4.2.8 Lipid Markers.......................................................................................................................46

4.3 Results ........................................................................................................................................47

4.3.1 Water Structure Across the Shelf........................................................................................47

4.3.2 Total Carbon and Grain Size...............................................................................................51

4.3.3 Organic Markers..................................................................................................................52

4.3.4 Fatty Acids and Sterol Biomarkers......................................................................................55

4.3.5 Meiofaunal Community .......................................................................................................56

4.4 Discussion...................................................................................................................................59

4.5 Summary.....................................................................................................................................62

4.6 Future Research .........................................................................................................................62

5 Conclusions.........................................................................................................................................63

6 References..........................................................................................................................................64

Appendix A: 2015 Post-Cruise Report ........................................................................................................67

Appendix B: Feeding Guilds and Abundance .............................................................................................95
iii

List of Figures

Figure 1. Slocum G2 Glider........................................................................................................................... 5

Figure 2. Planned 2016 glider mission, showing locations of proposed moorings.......................................6

Figure 3. Map of the Mackenzie Trough. Bathymetry from the National Oceanic and Atmospheric 

Administration (NOAA) and bathymetry contours from Geological Survey of Canada...............................10

Figure 4. Climatology plot of Mackenzie River discharge for the period 1973 to 2011. .............................11

Figure 5. Wind rose histograms for Herschel Island (2006–2017) for August, September, and October. .12

Figure 6. Plot of wind vectors and speed....................................................................................................13

Figure 7. Map of the Mackenzie Trough region overlaid with glider tracks (purple) and depth-average 

velocity estimates (blue arrows)..................................................................................................................14

Figure 8. Plots of potential temperature (left) and salinity (right) versus days of deployment (August 15–

October 6, 2016). ........................................................................................................................................15

Figure 9. Temperature-Salinity (T/S) plot for MARES 2016 glider deployment..........................................16

Figure 10. Plots of: (a) chlorophyll-a fluorescence, (b) CDOM fluorescence, (c) dissolved oxygen 

saturation, and (d) optical backscattering for the MARES glider study from August 15, 2016, to October 6, 

2016. ...........................................................................................................................................................17

Figure 11. Time series of the photosynthetically available radiation (PAR). ..............................................18

Figure 12. Satellite MODIS remote sensing true color images of the Mackenzie Trough region from late 

August to early October 2016. ....................................................................................................................19

Figure 13. Mixed layer depth (MLD) during the glider deployment.............................................................20

Figure 14. Sub-mesoscale variability in the along-canyon axis transect from Sept.11–16, 2016. .............21

Figure 15. Plot of temperature and salinity as well as heat and salt fluxes for two along-canyon axis glider 

transects......................................................................................................................................................22

Figure 16. NARR daily composite of surface vector winds for the Mackenzie Trough region....................23

Figure 17. Glider path (blue) and glider estimated depth-averaged velocities (red arrows) overlaid on top 

of HYCOM sea surface height field and depth-averaged currents (upper 200 m of the water column).....24

Figure 18. Cross-shelf glider sections of temperature and salinity showing the hydrographic responses 

during strong eastward flow (left panel) and strong westward flow (right panel) conditions. .....................25

Figure 19. Top panels: NARR monthly mean surface winds for September 2011 (left) and September 

2016 (right). Bottom panels: HYCOM depth-averaged currents and sea surface heights for September 

2011 (left) and September 2016 (right).......................................................................................................26

Figure 20. Climatological NARR winds for (a) July, (b) August, (c) September, and (d) October..............27

Figure 21. Average NARR surface summer (July–October) winds for (a) 2012–2017, (b) 2005–2011, (c) 

2000–2004. (d) An illustration of the major currents in the Chukchi and Beaufort Seas (adopted from 

Schulze et al. 2013). ...................................................................................................................................28
iv

Figure 22. Summertime zonally averaged wind speed for the Chukchi-Beaufort shelf and slope region 

(1948 to 2017 NCEP reanalysis). ...............................................................................................................30

Figure 23. Profile plot of glider temperature (red), chlorophyll-a (green), light (blue), and density (black) 

measurements for two glider transects during MARES 2016.....................................................................32

Figure 24. Locations of the moorings comprising the composite MARES/UAF/DFO array (see the legend). 

Also shown are the locations of the CTD stations occupied during the deployment cruise. ......................33

Figure 25. WHOI moorings M1 and M2. .....................................................................................................35

Figure 26. Mooring M3 and M4 (ASL).........................................................................................................36

Figure 27. Instrumentation on the UAF, WHOI, and ASL moorings. ..........................................................37

Figure 28. Vertical section of potential temperature (oC, color), as estimated from the CTD casts, overlain 

by potential density (kg/m3, contours), occupied during the deployment cruise.........................................40

Figure 29. Vertical section of potential salinity, as estimated from the CTD casts, and locations of the 

UAF, WHOI, and ASL moorings. ................................................................................................................41

Figure 30. Profiles of water data collected at the mooring locations and at the midpoint along the MARES 

mooring line in October 2016 (note different y-axis scales for each row of data).......................................42

Figure 31. Physical parameters of station M1 at the time of sampling. ......................................................48

Figure 32. Physical parameters of station M2 at the time of sampling. ......................................................49

Figure 33. Physical parameters of station M3 at the time of sampling. ......................................................50

Figure 34. Physical parameters of station M4 at the time of sampling. ......................................................51

Figure 35. Grain size across the four shelf stations of the Mackenzie shelf transect.................................52

Figure 36. Measure of total hydrolysable amino acids (THAA) normalized to organic carbon microgram in 

particles and sediments across the Mackenzie shelf..................................................................................53

Figure 37. Distribution of individual amino acids in each sample represented in a unit of relative 

abundance, percent of each amino acid that contributes toward the total sum of all amino acids in that 

sample.........................................................................................................................................................54

Figure 38. A) The % GABA as fraction of total amino acids in surface sediments across the MARES 

transect plus the AIM pelagic site for comparison. B) The % GABA as fraction of amino acids in POM 

collected at the fluorescence maximum at available water column sites. ..................................................55

Figure 39. The distribution and abundance of major sterol markers plus phytol across the Mackenzie shelf 

transect........................................................................................................................................................56

Figure 40: Meiofaunal abundances and biomass that represent the majority of the benthic community in 

the meio size range.....................................................................................................................................59

Figure 41. Lipid and amino acid biomarkers of marine origin (panel A) verses summed organic markers 

both of terrestrial and marine organic matter (panel B). .............................................................................61
v

List of Tables

Table 1. UAF, WHOI, and ASL moorings deployed on the CCGS Sir Wilfrid Laurier cruise......................38

Table 2. List of the instrumentation contained on the WHOI and ASL moorings. ......................................38

Table 3. Sampling locations for water and sediment collections. ...............................................................44

Table 4. Water column sample collection and depths (m) at each station. ................................................44

Table 5. Locations of sediment collections for organic and meiofaunal analysis .......................................45

Table 6. Organic carbon content of all samples from the water column and surface sediments. ..............52

Table 7. Calculated wet and dry weight biomass (grams) based on literature values for major meiofaunal 

taxonomic groups identified from MARES cross-shelf transect..................................................................58
vi

List of Abbreviations and Acronyms

ADCP acoustic doppler current profiler

AEWC Alaska Eskimo Whaling Commission

AIM artic ice monitoring

AOOS Alaska Ocean Observing System

ASCII American Standard Code for Information Interchange

ASL ASL Environmental Science, LLC

AURAL aural whale recorder

AUV autonomous underwater vehicle

AZFP acoustic zooplankton fish profiler

BOEM Bureau of Ocean Energy Management

CCGS Canadian Coast Guard Ship

CDOM colored dissolved organic matter

CO Contracting Officer

COR Contracting Officer’s Representative

CTD conductivity-temperature-depth

db decibar

DBD Dinkum Binary Data (other file formats: SBD, EBD, TBD)

DFO Department of Fisheries and Oceans, Canada

DIC dissolved inorganic carbon 

DO dissolved oxygen

EOSDIS Earth Observing System Data and Information System

ESI electrospray ionization

FJMC Fisheries Joint Management Council

g/OC gram per organic carbon

GABA gamma aminobutyric acid

GC-MS gas chromatography-mass spectrometry

GOFS Global Ocean Forecast System

GPS global positioning system

HCl hydrogen chloride

HTC Hunters and Trappers Committee

HYCOM Hybrid Coordinate Ocean Model

IBCAO International Bathymetric Chart of the Arctic Ocean

IGC Inuvialuit Game Council

IOS Institute of Ocean Sciences

IPS ice profiling sonar

LC-MS liquid chromotography-mass spectrometry

M mol

MARES Marine Arctic Ecosystem Study

mg/L milligrams/liter

MLD mixed layer depth

μm micron

μmol/L micro-mol/Liter
vii

MODIS Moderate Resolution Imaging Spectroradiometer

MS Mass Selective

Mt metric ton

m/z mass divided by charge number

N normal

NaOH sodium hydroxide (a salt)

NARR North Atlantic Regional Reanalysis

NCEP National Centers for Environmental Prediction

NCODA Navy Coupled Ocean Data

nm nautical miles

NOAA National Oceanic and Atmospheric Administration

ODU Old Dominion University

ORE PORT acoustic release

PAR photosynthetically active radiation

PFTBA perfluorotributylamine

PI Principal Investigator

POC particulate organic carbon

POM particulate organic matter

ppb parts per billion

psu practical salinity unit

PUFA polyunsaturated fatty acid

QA/QC quality assurance and quality control

RGB red-green-blue color space

RO reverse osmosis

RSLC rapid separation liquid chromatography

SOP synthetic ocean profile

Sv salt transport; 1 Sv=106 m3/s

THAA total hydrolysable amino acids

TOC total organic carbon

T/S temperature/salinity

T/S/P temperature/salinity/pressure

TW terrawatt

TWR Teledyne Web Research

UAF University of Alaska Fairbanks

ULS upward looking sonar

USCGC United States Coast Guard Cutter

UV ultraviolet

V volt

VIMS Virginia Institute of Marine Science

WHOI Woods Hole Oceanographic Institute

XBT expendable bathythermograph
1

1 Overview

1.1 Background

The Department of the Interior, Bureau of Ocean Energy Management (BOEM) and its partners, ONR, 

NOPP, Shell, USARC, US Coast Guard, seek to advance knowledge of the Arctic marine ecosystem. The 

Marine Arctic Ecosystem Study (MARES) arose from increased attention on climate change, energy 

development, and related sustainability issues in the Arctic. Results from this study are intended to inform 

government, industry, and communities on regulatory needs, operational challenges, and resource 

management and provide important context for economic development, environmental protection, 

sustainability of local communities, and health and safety.

The focus area of MARES is the eastern Beaufort Sea shelf from Kaktovik to the Mackenzie Delta 

coastline to a depth of 1,000 m. The overarching scientific goal of MARES, as initially envisioned, was to 

increase our understanding of the impact of physical drivers (ocean, ice, atmosphere) on the trophic 

structure and function of the marine ecosystem on the Beaufort shelf with special attention to the 

implications on marine mammals and local communities. The intent was to implement an integrated, 

multidisciplinary study combining retrospective analyses, field studies, modeling, and synthesis spanning 

atmosphere, ice, physical, chemical, and biological oceanography from benthos to fish, marine mammals, 

and people.

1.2 Biophysical and Chemical Program Goals and Objectives

The Biophysical and Chemical Program is one component implemented to support the broader MARES 

objectives. The goals of this component were to: 

• Collect physical, biological, and chemical observations in the Eastern Beaufort Sea from moving 

and moored platforms

• Describe and analyze physical, biological, and chemical observations acquired from the moving 

platforms

• Simultaneously with the mooring deployment operation, gather water and sediment samples at 

the mooring locations and process and analyze these samples to estimate the carbon budget and 

describe carbon cycling processes

These objectives were implemented through a field program conducted in 2016 and took advantage of 

some new partnership opportunities fostered by Stantec.

1.3 Study Design and Implementation

1.3.1 Study Design

Stantec partnered with Old Dominion University (ODU), Woods Hole Oceanographic Institution 

(WHOI), ASL Environmental Sciences (ASL), Virginia Institute of Marine Sciences (VIMS), Department 

of Fisheries and Ocean Canada (DFO), University of Washington (UW), University of Alaska Fairbanks 

(UAF), and Kavik-Stantec Inc. to conduct community consultations and collect and analyze biophysical 

and chemical data needed to fulfill the objectives and goals of this study. Field and analytical study 

components developed were: 
2

• Deployment of a glider to profile transects in the same region as the mooring deployment and 

provide high resolution biophysical and chemical data

• Deployment of moorings to acquire biophysical and chemical time series in the study region

• Sampling benthic carbon near the moorings that transected the Mackenzie River-Yukon Shelf 

region. 

These three field and study components provided an integrated approach to describe the biogeochemical 

impact of the Mackenzie River plume in the study area. A total of five moorings (three on the shelf and 

two on the shelfbreak) were deployed for approximately 12 months. These provided a continuous 

biophysical and chemical time series, as well as calibration data for the glider sensors. The moorings were 

equipped with a combination of sensors to measure fluorescence, conductivity, temperature, depth, 

current velocities, abundance of zooplankton and fish, and passive acoustics. To provide additional, high 

resolution data in the region of the moorings, an autonomous glider was equipped with similar sensors to 

measure oxygen, fluorescence, conductivity, temperature, depth, current velocities, and abundance of 

zooplankton and fish. The glider collected data along the mooring array and along the shelf and 

shelfbreak. The benthic carbon sampling was intended to provide estimates on carbon cycling processes 

associated with the Mackenzie River plume. 

1.3.2 Implementation 2015

There was an initial field effort in 2015 that planned for deployment of an autonomous glider between 

Kaktovik, AK, and the McKenzie Delta for approximately six weeks starting in mid-August, and 

deployment of a biophysical and chemical mooring array in the eastern US Beaufort Sea along the USCanada border.

The United States Coast Guard Cutter (USCGC) Sycamore was loaded with mooring equipment in 

Cordova, AK, and arrived at the study location on September 1, 2015, with all mooring devices on board. 

To avoid interfering with subsistence whaling activities, BOEM and the Alaskan Eskimo Whaling 

Commission agreed on August 21, 2015, to proceed with mooring deployment when the communities of 

Nuiqsut and Kaktovik had completed their annual harvest of bowhead whales. On station, the USCGC

Sycamore waited for the completion of the harvest. Due to deteriorating sea conditions and much 

prolonged subsistence whaling activities, the vessel was eventually forced to return to port, leaving the 

area on September 22, 2015, without deploying the mooring devices. The 2015 post-cruise report 

summarizing all events during the 2015 field season is available in Appendix A.

The AUV Slocum G2 Glider equipped with Seabird pumped CTD, WETLabs ECO Triplet, Aanderaa 

dissolved oxygen optode, and Imagenex Model 853 scientific echo sounder was deployed from USCGC

Sycamore on September 21, 2015, immediately east of Kaktovik. The field crew stayed with the glider for 

the first 24 hours as planned and detected a leak during its first dive to 200 m. The glider was 

immediately recovered. Unfortunately, the leak could not be repaired in the field, and the mission was 

aborted. Later investigations found that the leak was caused by a manufacturing error, which was 

resolved, and the equipment was re-tested (see Appendix A).

1.3.3 Implementation 2016

After the aborted 2015 field season, the scope of the component was changed to reflect lessons learned 

and to take advantage of some new partnership opportunities Stantec had fostered in the interim. 

Specifically, the 2016 field program added partnerships with the Department of Fisheries and Oceans 

(DFO) Canada and the University of Alaska Fairbanks (UAF). It included a six-week deployment of an 

autonomous glider between mid-August and early October 2016 in the eastern Beaufort Sea centered on 

the Mackenzie Trough, the deployment of four MARES plus two partner moorings in early October 2016 
3

in the eastern Beaufort Sea just east of Hershel Island, and carbon cycling measurements at the mooring 

sites.

1.4 Community Consultations

2015 Consultations

In 2015, BOEM conducted all consultations with the Alaska Eskimo Whaling Commission (AEWC)

regarding the 2015 field program. The BOEM Contracting Officer’s Representative (COR) described the 

mooring deployment plans that were to take place on board the USCGC Sycamore and associated timing 

and communications protocols with the AEWC. After the field program was amended to 2016 

deployments, consultations, conducted by Kavik-Stantec Inc. with the Inuvialuit Game Council (IGC),

were held on December 18, 2015, in Aklavik, Northwest Territories, to introduce the program and gain 

feedback. The IGC had no concerns with the mooring program.

2016 Consultations

In Winnipeg, Manitoba, Canada, in February 2016, the Fisheries Joint Management Committee (FJMC) 

held a meeting where Stantec presented the field program planned for 2016 to get feedback. The FJMC

expressed support for the mooring, glider, and benthic program. 

Kavik-Stantec Inc. held consultation meetings with the Inuvik Hunters and Trappers Committee (HTC), 

Tuktoyaktuk HTC, and the Aklavik HTC, on June 22, 23, and 24, 2016, respectively, regarding the 2016 

field program. Each HTC supported the program and were interested in seeing results from the study.

A project summary was submitted to the Inuvialuit Settlement Region Environmental Impact Screening 

Committee to determine if the project required an Environmental Screening. On August 2, 2016, the 

Environmental Impact Screening Committee (AEWC) determined that the project does not meet the 

definition of development as defined under the Inuvialuit Final Agreement, and as a result would not 

require an Environmental Impact Screening. 

BOEM conducted consultations with the AEWC, and presented the field program at the AEWC meeting 

held February 1–5, 2016 in Utqiaġvik, Alaska. 

2017 Consultations

Kavik-Stantec Inc. consulted with the Tuktoyaktuk HTC on April 12, 2017, the Aklavik HTC on April 

13, 2017 and the Inuvik HTC on April 20, 2017 concerning the 2017 field program and as a follow up to 

the 2016 program. The HTCs did not have any concerns with the programs. 

Stantec submitted a Memo to the IGC on June 9, 2017, which provided information on the Alaska Ocean 

Observing System (AOOS) and access to the data. 

1.5 Permitting

Stantec and Kavik-Stantec Inc. gathered all necessary permits and permissions as outlined in the contract 

agreement including applicable permits from the Northwest Territories (Aurora Research Institute [ARI]).

The program was conducted by adding MARES to a cooperative agreement with DFO Canada previously 

held by ASL to conduct oceanographic research in the Canadian Beaufort Sea. Confirmation to conduct 

all activities under Task Order 3 were received.
4

2 AUV Glider Component

2.1 Introduction

An underwater autonomous vehicle—Slocum G2 Glider—was deployed in the summer of 2016 to 

advance our understanding of the exchange processes between the Mackenzie River, the shelf, and the 

eastern Beaufort Sea, and the impact of these exchanges on the ecosystem.

We aimed to test the following hypotheses:

• The Mackenzie River plume strongly affects the stratification and bio-optical properties of the 

surface mixed layer on both Canadian and US continental shelves

• River-shelf-basin exchange is strongly affected by seasonal heating and cooling, wind-driven 

advection, and interaction with shelfbreak frontal currents

• In the absence of strong wind forcing, buoyancy-driven shelf flow and the shelfbreak jet advects 

fresh Mackenzie River water eastward toward the Amundsen Gulf. Under moderate to strong 

easterly winds, however, the Mackenzie River plume is advected westward toward the Alaskan 

Beaufort Sea

• The Mackenzie River plume and wind forcing vary on time scale of 1 to 2 weeks driven by 

regional weather and variability of shelf and shelfbreak circulation

Working toward the scientific objectives of MARES, Principal Investigator (PI) Gong of the VIMS led 

the effort to prepare, deploy, and recover one Teledyne Webb Research (TWR) Slocum G2 Glider in the 

eastern Beaufort Sea. The glider study complemented the ongoing mooring component in the study 

region. This chapter contains the main results of the 2016 glider study. 

2.2 Methods

2.2.1 Glider Setup and Sensor Suite

One Slocum G2 Glider (Figure 1), powered by lithium primary batteries, was used for the study. The 

glider is a self-powered AUV. It undulates up and down the water column, between the surface and 200 

m, sampling the ocean. The glider has an endurance of 1–3 months depending on battery type and number 

of sensors and it can travel for a couple thousand miles on its own power. The glider moves slowly 

through the water at approximately 0.5 knots. The glider hull is made of composite material holding a 

partial vacuum inside. The hull can be damaged through scrapes, impacts, drops, and over-pressurization. 

The glider's scientific sensors are all located in the middle section.
5

Figure 1. Slocum G2 Glider.

The glider was equipped with an extended buoyancy 200 m buoyancy pump and a hybrid thruster; both 

were designed to deal with freshwater lens penetration when the extreme buoyancy range of a river plume 

is encountered. The glider’s scientific sensor suite included Seabird CTD, WET Labs ECO Puck

3-channel fluorometer which provides measurements for chlorophyll-a, Colored Dissolved Organic 

Matter (CDOM), optical backscattering (700 nm), Aanderra Dissolved Oxygen optode, Biospherical 

Photosynthetically Active Radiation (PAR) sensor, and Imagenex 120 kHz acoustic echosounder. All 

sensors were factory calibrated.

The glider was set to surface every 2–3 hours, calling the dockserver at VIMS to upload a subset of the 

data for piloting and real-time analysis. The real-time data contained decimated data. The delayed-mode 

dataset contained full resolution data.

2.2.2 Glider Preparation for 2016

Preparations were made at VIMS to ready the glider for the 2016 deployment. The glider was ballasted by 

adding salt to a tank filled with York River (Virginia) water until the density equaled that of the expected 

density of the Mackenzie Trough region during the time of deployment (1,022 kg/m3

). Internal weight 

was added to the nose, tail, and mid-sections of the glider so that roll and pitch were each approximately 

0°, and the tail floated about an inch above the water’s surface when in ballast mode. New O-rings were 

installed and lubed, and the internal surfaces at hull junctions were examined for scratches that could 

jeopardize the vacuum integrity.

A test deployment was conducted off Wachapreague, Virginia, on May 20, 2016, for five days, during 

which a leak developed. The glider was shipped back to TWR for re-examination. The leak was attributed 

to an improperly sized screw that was used by the manufacturer in the glider’s forward section. TWR 

completed the repair, re-ballasted the glider, and re-tested it down to 200 m depth near the New England 

shelfbreak on the June 23. The glider performed as required during this test and was shipped directly to 

Prudhoe Bay on July 1, 2016, in preparation for the field work in the eastern Beaufort Sea.

2.2.3 2016 Glider Survey Plan

MARES 2016 glider deployment focused on a biophysical study of the eastern Beaufort Sea in and 

around Mackenzie Trough region. The objectives of the glider mission were to: 

• Map the spatial distribution of the Mackenzie plume from the US-Canadian border to the head of 

the Mackenzie Trough
6

• Characterize the along-shelf and cross-shelf structure of the shelfbreak jet and shelf water masses 

near the Mackenzie Trough

• Quantify the associated biological response to the physical conditions of the water column

A survey plan was laid out with deployment of the glider north of Kaktovik in US waters, entering the 

MARES sampling region from the west on its own power. It was anticipated that the glider would 

perform a cross-shelf transect near the US-Canada border before proceeding to the Mackenzie Trough 

along the 60 m isobath. Once in the Mackenzie Trough region, the glider would repeat the proposed 

sampling pattern in the trough two to three times and end with a cross-shelf transect along the proposed 

mooring sites (Figure 2). The glider would then be recovered by the Canadian Coast Guard Ship (CCGS)

Sir Wilfrid Laurier after the completion of the mooring deployments (see Section 3). This plan would 

enable a later glider-mooring cross-shelf comparison, as well as provide additional spatial and temporal 

context to the moorings. 

Figure 2. Planned 2016 glider mission, showing locations of proposed moorings.

WHOI moorings in red, ASL moorings in blue, University of Alaska Fairbanks (UAF) mooring in black, Canadian 

moorings in green.

2.2.4 Glider Deployment

PI Gong’s research technician and graduate student traveled to Prudhoe Bay, AK on August 9, 2016 and 

picked up the glider on August 10. A functional checkout was preformed to ensure all systems and 

sensors were functioning as expected. This included checking the functionality of the altimeter, Digifin, 

thruster, nose recovery system, and leak detect. Next, the glider’s compass was calibrated to account for 

the difference in the Earth’s magnetic field in Alaska compared to Virginia. A structure was built using 

ladders and 2” x 4” boards and straps were used to suspend the glider from the boards. The True North 

Technologies Revolution Test program was used to measure the glider’s orientation, pitch, and roll while 

we rotated the glider 360° in a level, nose up, and nose down orientation and turned on either side. After 

Mackenzie 

Trough

Herschel 

Island

Alaska

Yukon
7

calibration, the accuracy was checked against a handheld compass at 30° intervals with the glider level, 

nose up, and nose down.

When the glider was ready, it was loaded onto a 60 ft coastal research vessel (R/V)—the R/V Ukpik. The 

R/V Ukpik arrived on station, 30 nautical miles north of Kaktovik in 200 m of water at the shelfbreak the 

morning of August 15, and the glider was readied for deployment. The sea state was very calm. 

Additional on-deck checks were performed to test the glider’s Iridium communication and GPS. The 

glider was placed into the water attached to a buoy, and the roll and pitch were observed to be within 

acceptable limits. A shallow test dive was completed successfully before removing the buoy. A deeper 

test dive was also conducted successfully before sending the gilder to its first waypoint. The R/V Ukpik

remained in the area for a short time to ensure the glider was flying well before heading back to port.

2.2.5 Piloting

The glider was piloted by PI Gong at VIMS throughout the mission. The glider performed nominally and 

successfully completed the planned mission. The glider was set to surface every 2 to 3 hours and upload 

real-time data while also receiving new mission updates (as needed). The glider experienced several

temporary aborts during the mission, mainly due to buoyancy issues as a freshwater lens was 

encountered. The glider was ballasted for a mean density of 1,022 kg/m3

. That means with the extended 

buoyancy pump, the glider should be able to handle ± 5.5 kg/m3 density units. We encountered water as 

fresh as 1,016 kg/m3 and as dense as 1,027 kg/m3

, which meant that at times, relying on buoyancy alone 

wasn't sufficient for bringing the glider back the surface. The hybrid thruster provided the glider with the 

capability of freshwater lens penetration using an additional 1,000 cc of active buoyancy from the 

thruster. The thruster was programmed to turn on automatically once upward/downward velocity dropped

to less than 0.1 m/s. Except for during two periods near the western wall of the trough when an 

exceptionally strong current (0.5 m/s or greater) was encountered, the glider was able to make it to all 

waypoints.

The total mission lasted 52 days for a total distance traveled of approximately 1,100 km. 

2.2.6 Glider Recovery

The glider was recovered on October 6, 2016, from the CCGS Sir Wilfrid Laurier. The recovery effort was 

led by the MARES mooring team from WHOI and ASL. PI Gong provided the procedural documentation 

to the ship’s recovery crew. The glider was recovered from a small boat then hoisted onto the larger ship. 

The sea condition was favorable, and the recovery was uneventful. The glider was stowed onboard using a 

custom built wooden frame as the CCGS Sir Wilfred Laurier did not have a glider cart. The glider remained 

on board until the CCGS Sir Wilfrid Laurier reached its home port at the Institute of Ocean Sciences (IOS)

in British Columbia.

2.2.7 MARES Glider Data Management and QA/QC

2.2.7.1 Data Retrieval and Archive

Once the glider arrived at the IOS in Victoria, Vancouver Island, British Columbia at the end of October, 

PI Gong downloaded the data and cleaned, inspected, and packed the glider for shipment back to VIMS. 

The raw data was downloaded from the glider. The original copy is archived at VIMS, and a copy of the 

raw data was uploaded to the AOOS Workspace. 

2.2.7.2 Data Format

Everything except for the echo sounder data was stored in Dinkum Binary Data (DBD) format. The raw 

engineering data was stored in SBD (decimated) and DBD (full) files. The raw science data was stored in 
8

TBD (decimated) and EBD (full) files. Real-time data processing used SBD and TBD files while delayedmode processing used all available data. Raw binary data from the glider was converted to Matlab 

readable ASCII format using ‘dbd2asc’ and ‘dba2_glider_data’ converters provided by TWR. 

2.2.7.3 CTD, DO, PAR, & Fluorometers

The glider used a pumped Seabird CTD and its performance was nominal throughout the mission. The 

CTD, DO, PAR, and ECO Puck all operated in an upcast only mode throughout the mission. The raw data 

files were converted to Matlab format for analysis. As configured, the glider’s pressure sensor and the 

science sensors recorded their data at an ‘as fast as possible’ setting; sampling frequencies nominally 

varied between 0.4 to 1 Hz and provided a vertical resolution between 0.15 to 0.35 meters. 

One technical issue encountered during data processing was temporal synchronization of the data time 

stamp, the pressure sensor values, and the different science sensors’ measurements. For each time stamp, 

if there is value from any of the sensors, their values are recorded. Otherwise, if a sensor does not report a 

value, then the value ‘NaN’ is recorded for that sensor at that time stamp. There were times when the 

pressure sensor values and the science sensors were at different times, which resulted in appearance of a 

‘data gap’ when the data was plotted simultaneously against pressure (depth) values and time. This was 

because the plotting routine required time, pressure, and data values to all be not “NaN’ before the data 

point could be plotted. To address this data synchronization issue and preserve the sampling fidelity of the 

glider as much as possible, the pressure values were linearly interpolated between data values so that 

there is guaranteed to be a pressure value for each time stamp. The glider’s flight dynamics are effectively 

constant over the sampling frequency of the sensors (~0.5 Hz), so the linearly interpolated pressure values 

are considered representative of the true pressure values. Once the interpolation was completed, the 

apparent ‘data gap’ issue was resolved. All CTD, DO, PAR, and fluorometer data (both raw and 

converted) have been archived on a server at VIMS and uploaded to the AOOS Workspace.

2.2.7.4 Echo Sounder

The echo sounder operated in a downcast only mode throughout the mission. It sampled every other cast. 

Raw echo sounder data was uploaded to AOOS Workspace for later processing. The processing and 

analysis of glider echo sounder data was not part of this Task Order.

2.2.8 Ocean Data and Ocean Model Output Used for Analysis

2.2.8.1 Wind data at Herschel Island

Wind data at Herschel Island is provided by a Canadian government weather station: 

http://climate.weather.gc.ca/climate_data/daily_data_e.html?StationID=1560. The station’s location is 

69.57 N, 138.91 W at an elevation of 1.2 m with a WMO ID of 71501. Data include temperature, air 

pressure, dew point, relative humidity, wind direction, wind speed, and wind chill and are available on an

hourly basis.

2.2.8.2 North American Regional Reanalysis (NARR)

The North American Regional Reanalysis (NARR) model is produced by the National Centers for 

Environmental Prediction (NCEP) https://www.esrl.noaa.gov/psd/data/gridded/data.narr.html. The NARR 

model has monthly, daily, and eight-times daily temporal coverage beginning in 1979. Vector wind data 

at the surface level in the region of deployment was extracted from the model output for different periods 

of interest. We used daily and monthly output in our analysis.
9

2.2.8.3 Global Hybrid Coordinate Ocean Model

The US Navy’s Global Hybrid Coordinate Model (HYCOM) is used for our analysis of regional scale 

circulation patterns on event to inter-annual timescales. HYCOM has a coordinate system that is 

isopycnal in the open, stratified ocean but smoothly reverts to a terrain-following coordinate in shallow 

coastal regions and to z-level (vertical) coordinates in the mixed layer and/or unstratified seas. The Global 

HYCOM is a 1/12th degree model that assimilates available satellite altimeter observations, satellite, and 

in situ sea surface temperature as well as in situ vertical temperature and salinity profiles from expendable 

bathythermograph (XBTs), Argo floats and moored buoys. The model uses the Navy Coupled Ocean 

Data Assimilation (NCODA) 3D-Var system. Surface information is projected downward into the water 

column using Improved Synthetic Ocean Profiles (Helber et al. 2013). The Naval Research Lab generates 

daily nowcast of the 3-D ocean field of temperature, salinity, surface elevation, and horizontal current 

velocities in near real-time. For this study, we used model output results from HYCOM GOFS 3.0 with 

32 vertical layers. In particular, output from expt_19.1, expt_90.9, expt_91.0, expt_91.1, and expt_91.2 

were used in our analysis of the flow field in and around Mackenzie Trough. For more information, 

please visit (https://hycom.org/dataserver).

2.2.8.4 MODIS True Color Ocean Imagery

True color ocean images from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite is 

retrieved using WorldView (https://earthdata.nasa.gov/labs/worldview/). It’s a web-based tool from 

NASA's Earth Observing System Data and Information System (EOSDIS) that allows interactive 

browsing of global satellite imagery from MODIS within hours of data being acquired. High resolution 

RGB images from WorldView are output in Keyhole Markup Language (KML) format and plots in 

Google Earth.

2.3 Results

2.3.1 Characterization of the Physical Oceanographic Setting

The physical oceanographic setting can be characterized in three parts: geography of the Mackenzie 

Trough, Mackenzie River discharge, and winds.

2.3.1.1 Geography of Mackenzie Trough

The Mackenzie Trough incises the eastern Beaufort shelf (Figure 3). It is situated to the west of the mouth 

of the Mackenzie River by approximately 80 km. The trough is 120 km long, 65 km wide, 370 m deep at

the mouth, and 200 m deep at the center. Shallow and wide continental shelves flank the two sides of the 

Mackenzie Trough. 
10

Figure 3. Map of the Mackenzie Trough. Bathymetry from the National Oceanic and Atmospheric 

Administration (NOAA) and bathymetry contours from Geological Survey of Canada.

The shelf to the west is 65 km wide and 50 m deep while the shelf to the east is 150 km wide and 80 m 

deep. The trough terminates at the continental slope and does not extend into the Beaufort Sea basin. The 

shelfbreak is located at the 70 m isobath. The 40 m isobath situated mid-shelf delineates the inner shelf 

and the outer shelf regions. Going shoreward from the shelfbreak, there is a ridge and a valley just 

shoreward of the 60 m isobath with a peak (45 m deep) to valley (60 m deep) depth range of 15 m. This 

bathymetric feature extends for 150 km to the west of Mackenzie Trough.
11

2.3.1.2 Mackenzie River Discharge

The Mackenzie River has a highly seasonal discharge pattern. Climatological analysis show that the 

annual average discharge is 9,900 m3

/s. The seasonal discharge rapidly peaks in spring at Year Day 148 

(May 27) with an average maximum of 22,500 ± 12,500 m3

/s (see Figure 4). The discharge gradually 

decreases through the summer down to the annual mean discharge by Year Day 286 (October 12). A more 

rapid drop in the fall lowers the discharge rate to 4,000 m3

/s by Year Day 328 (November 20), which is 

the wintertime average discharge from late November to late April. The MARES glider study took place 

from August 15 to October 6 (highlighted in red in Figure 4). During this time, the climatological river 

discharge was 14,000 ± 6,000 m3

/s at the beginning of the deployment and 10,000 ± 2,500 m3/s by the 

end of the deployment.

Figure 4. Climatology plot of Mackenzie River discharge for the period 1973 to 2011. 

Figure adapted from Yang et al. (2015). The red region highlights the period when the MARES glider was deployed.

2.3.1.3 Winds

2.3.1.3.1 Climatological Winds

Climatological analysis of winds measured from the Canadian weather station on Herschel Island show 

that for the months of August, September, and October, the wind directions are predominantly 

southeasterly (35–45% of total) and northwesterly (25–35% of total) (Figure 5). Wind speed ranged from 

0 m/s to 20 m/s. The winds are weakest and more likely to be northwesterly (downwelling favorable) in 

August, and strongest and more likely to be southeasterly (upwelling favorable) in October.
12

Figure 5. Wind rose histograms for Herschel Island (2006–2017) for August, September, and 

October.

2.3.1.3.2 Winds During the 2016 Field Season

Winds in the Mackenzie Trough region during the MARES 2016 glider study were highly variable 

(Figure 6), oscillating between southeasterly (upwelling favorable) and northwesterly (downwelling 

favorable) on a time scale of 1 to 3 days during the first part of the study (August 15 to September 2, 

2016). Wind speeds during this first period ranged from 2–13 m/s. From September 2 to 10, strong 

northwesterly winds persisted (6–14 m/s), followed by moderate easterly upwelling favorable winds from 

September 11 to 15 (3–9 m/s). From September 15 to 25, winds were variable (1–7 m/s) except for brief 

period of westerly downwelling winds from September 18 to 20 (6–10 m/s). From September 15 to 25, 

winds were variable (1–7 m/s) except for brief period of westerly downwelling winds from September 18 

to 20 (6–10 m/s). From September 26 to October 1, winds were predominantly northwesterly (1–12 m/s). 

Finally, the last period of study, from October 1 to 4, winds were persistent southeasterly upwelling 

favorable (3–13 m/s). The glider surveyed the Mackenzie Trough three times over the course of the study 

with each pattern taking approximately 10 days and each transect lasting 2 to 5 days. Throughout the 

study, given the variable winds, the glider likely experienced different wind-forced circulation even 

during a single transect. 
13

Figure 6. Plot of wind vectors and speed (2016). 

Top panel shows wind vectors from Herschel Island and the bottom panel shows wind vectors from NARR at the 

mouth of the Mackenzie Trough. The blue segments represent northeasterly winds and red segments represent 

southwesterly winds.

2.3.2 Hydrography & Water Masses

Mackenzie Plume: During the 2016 MARES deployment, the glider traveled from the Alaska Beaufort 

shelf to the Mackenzie Trough before completing three repeat pattern surveys (Figure 7).
14

Figure 7. Map of the Mackenzie Trough region overlaid with glider tracks (purple) and depthaverage velocity estimates (blue arrows).

Red lines indicate idealized transect plans and transect sections.

As the glider progressed from west to east in late August, it began to encounter warm (> 4 °C) and fresh 

(< 27 psu) riverine water at the surface (Figure 8). The freshest river plume water was found inside 

Mackenzie Trough with salinity less than 23 psu. The thickness of the Mackenzie River plume varied 

between 5 m and 15 m.
15

Figure 8. Plots of potential temperature (left) and salinity (right) versus days of deployment 

(August 15–October 6, 2016). 

Surface water fresher than salinity of 27 are attributed to Mackenzie River plume.

Surface Mixed Layer: In general, the surface mixed layer had temperatures between 2 °C and 8.5 °C and 

salinity less than 28 psu. The warmest water was found during the first half of the deployment in and 

around the Mackenzie plume. The mixed layer temperature cooled rapidly during a couple of mixing 

events in the second half of September. Except inside the core of the river plume, the mixed layer salinity 

was relatively uniform with salinity between 26.5 psu and 28 psu. The halocline depth varied between the 

shallow shelf region and the deeper water offshore from mid-August to mid-September.

Pacific Water: Below the upper mixed layer resides Pacific winter and summer water. Pacific summer 

water generally had temperatures between -1 °C and 2 °C and salinity between 29 psu and 32 psu at 

depths between 80 m and 100 m. Pacific winter water had temperatures less than -1 °C and salinity 

greater than 32 psu and was found at depths between 80 m and 200 m. At two times during the study, one 

on September 18 and the other on October 3, a large amount of Pacific winter water was upwelled onto 

the continental shelf to the west of the Mackenzie Trough.

Atlantic Water: The average depth that delineates Pacific winter water and the warmer Atlantic water in 

the western Arctic is 200 m (Shimada et al. 2005, Steele et al. 2004). The MARES glider detected a hint 

of Atlantic Water at a depth of 180 m indicated by the saltiest water at temperatures above -1 °C shown in 

the T/S plot (Figure 9). Atlantic water was only found in the deeper slope and basin region and none was 

found on the continental shelf or on the flanks of the Trough. The property of the Atlantic water was 

constant throughout the study.
16

Figure 9. Temperature-Salinity (T/S) plot for MARES 2016 glider deployment. 

The colors indicate potential density anomaly. The gray dots in each panel represent the T/S for one glider transect 

overlaid on the T/S for the entire mission. The left panel is for transect in early September, and the right panel is for a 

transect in early October.

Intra-seasonal evolution of the water masses: The Temperature-Salinity (T/S) diagram for the MARES 

glider mission is shown in Figure 9. It illustrates the large range of densities encountered by the glider 

during the study ranging from 1,016 kg/m3 in the freshest Mackenzie plume to 1,027 kg/m3 at a depth of 

190 m offshore. A comparison of the T/S from early September with T/S from early October shows the 

drastic cooling and salting throughout the upper water column, especially in the surface mixed layer. 

Below the pycnocline, at depths deeper than 60 m, there was no meaningful intra-seasonal variability.

2.3.3 Circulation Based on Glider Observations

The glider encountered different flow conditions. Depth-averaged velocities ranged from 0 cm/s to 

60 cm/s and along the walls of the trough was predominantly along-isobath. Cross isobath flow was seen 

on the shelf to the west and in the center of the Mackenzie Trough. During periods of substantial 

northwesterly downwelling-favorable winds, the depth-averaged flow was predominantly along-isobath 

eastward. During periods of substantial southeasterly upwelling-favorable winds, the flow was directed 

westward. The fastest flow was found on the western wall of the trough offshore of Herschel Island with 

speeds greater than 50 cm/s in both directions. There is also evidence of a cyclonic eddy on the eastern 

part of the Mackenzie Trough in late October.

2.3.4 Characterization of the Bio-Optical Conditions

2.3.4.1 Chlorophyll-a Fluorescence

Overall, chlorophyll-a concentrations in the Mackenzie Trough region tended to range between 0.2–

1 μg/l, with elevated levels observed in the first half of deployment reaching 1.4–2 μg/l (Figure 10). 

These localized areas of high concentration were identified at the surface and 20 m depth. Less variability 

was observed from day 30 onward with values 0.7 μg/l or lower. These dense patches may represent late 

summer blooms in the Mackenzie Trough region during the short ice-free period. There is a clear 

variation in the depth of the chlorophyll maxima between the shelf and the deeper slope regions. Whereas 

the chlorophyll maxima are limited to the upper 20 m of the water column on the shelf, the sub-surface 

chlorophyll maximum is present at a depth range of 40 m and 60 m in deeper water.

9/1/16 — 9/5/16 10/2/16 — 10/5/16
17

Figure 10. Plots of: (a) chlorophyll-a fluorescence, (b) CDOM fluorescence, (c) dissolved oxygen 

saturation, and (d) optical backscattering for the MARES glider study from August 15, 2016, to 

October 6, 2016.

2.3.4.2 CDOM Fluorescence

Observed CDOM values ranged from 1–4 ppb with the highest concentrations observed at the surface 

between days 10–35 of deployment (Figure 10). The near-surface high CDOM values are essentially 

tracers for the Mackenzie River plume. Outside of these localized maxima, values in the upper 40 m of 

the water column fell between 1–1.5 ppb while areas below 60 m tended to be consistent at approximately 

3 ppb. Near-bottom CDOM values were also elevated due to particulate resuspension with values ranging 

from 2.5 ppb to 3.5 ppb.

2.3.4.3 Dissolved Oxygen

Dissolved oxygen saturation decreased with depth with the highest values near the surface for the first 

half of the deployment and slightly deeper for the second half (Figure 10). Oxygen supersaturation in the 

upper 60 m of the water column implies primary production and surface mixing are contributing oxygen 

a. b.

c. d.
18

to the surface waters. This is corroborated by the variable wind patterns during the first half of the survey 

period, as well as elevated chlorophyll-a and CDOM.

2.3.4.4 Optical Backscattering

Backscatter was highest near the ocean bottom and in patches near the surface, coinciding closely with 

areas of observed elevated CDOM and chlorophyll-a levels (Figure 10). Suspension of sediments driven 

by turbulent mixing near the sea floor as well as the canyon head and shelfbreak areas contribute to the 

observed high backscattering levels.

2.3.4.5 Photosynthetically Available Radiation (PAR)

We observed day to day variability in the PAR data (Figure 11). On clear days, the euphotic zone 

extended down to 40 m while on cloudy days, the euphotic zone did not extend past 20 m. PAR data for 

the upper 5 meters is available during the dives when the glider is surfacing or at the surface; else, the 

glider normally flies below the upper 4 meters. 

Figure 11. Time series of the photosynthetically available radiation (PAR).

2.3.5 Variability of Hydrography and Circulation

2.3.5.1 Mackenzie River Plume

The Mackenzie River plume can be seen in satellite remote sensing images (Figure 12). The plume had 

varying spatial distributions during the glider mission. The images show the plume in these 

configurations: offshore, shoreward, eastward, and westward. The area near Herschel Island on the 

western side of the Mackenzie Trough shows the persistent presence of plume water regardless of the 

general plume configuration. The highest plume concentration is found at the mouth of the Mackenzie 

River to the southeast. The plume tends to be wider during easterly (October 2, 2016) and southerly 

(August 28, 2016) winds and more confined to the coast during westerly (September 19, 2016) and 

northerly (September 8, 2016) winds. The central (and deeper) parts of the trough have low 

concentrations of river plume water. Only with westerly winds is a substantial amount of Mackenzie 

plume water seen on the continental shelf to the west of the trough (October 2, 2016). Cloudy days 

prevented good satellite coverage for a large part of the field study; therefore, only representative plume 

conditions during different times of the study are shown.
19

Figure 12. Satellite MODIS remote sensing true color images of the Mackenzie Trough region from 

late August to early October 2016.

The Mackenzie plume can be seen advected in different directions depending on circulation in the Mackenzie Trough 

at those times.

2.3.5.2 Mixed Layer Depth

The mixed layer depth for the entire glider deployment is shown in Figure 13. The mixed layer was 

marked as the depth of maximum stratification in the water column. The thermocline shoaled from 15 m 

in the Alaskan Beaufort Shelf in mid-August to 7 m at the head of the Mackenzie Trough in late August. 

The average mixed layer depth (MLD) on the shelf was 10–15 m deep, and off the shelfbreak, it was 20–

25 m deep.

August 28, 2016

Offshore flow plume configuration

September 8, 2016

Shoreward flow plume configuration

September 19, 2016

Eastward flow plume configuration

October 2, 2016

Westward flow plume configuration
20

Figure 13. Mixed layer depth (MLD) during the glider deployment.

The MLD loosely tracks the thermocline but closely tracks the halocline due to the greater influence of 

salinity in the Arctic. Inside the Mackenzie Trough, the MLD increased from less than 10 m in early 

September to 25 m by late September. The MLD held steady at 25 m from late September into early 

October. On the event timescale, MLD varied in response to wind forcing and shelfbreak boundary 

current dynamics. The deepening of the MLD tends to be associated with specific surface mixing events. 

Two substantial MLD deepening events occurred: one in early September when the average MLD 

dropped from 7 m to 15 m, and another around September 22 when the average MLD deepened further 

from 15 m to 25 m; in both cases, when the glider was conducting the along-trough-axis survey 

approximately centered in the Mackenzie Trough. The winds turned from easterly to strongly westerly 

during the first event, and the winds were westerly downwelling favorable during the second event.

2.3.5.3 Sub-Mesoscale Variability

The glider’s high spatial resolution allowed it to capture events and processes that take place at the submesoscale (i.e., approximately 0.5 km to 1 km or approximately 2 to 4 hours). A good example of such an 

event is shown in an along-canyon axis transect from September 11–16, 2016 (Figure 14). During this 

time, the flow is southwestward. The glider captured what appears to be an internal wave bore-like 

phenomenon that caused large horizontal temperature and salinity gradient near the head of the trough 

just below the pycnocline. The bore-like phenomenon encapsulated water with high chlorophyll 

fluorescence and high optical backscatter. There were several such high frequency variabilities in the 

glider’s hydrographic and bio-optical data. Future detailed inspections of each event will be required to 

understand the drivers and significance of these events.
21

Figure 14. Sub-mesoscale variability in the along-canyon axis transect from Sept.11–16, 2016.

The black circle identifies the internal wave bore-like phenomenon. 

2.3.5.4 Heat and Salt Transport

The heat and salt flux for each MARES glider section was calculated. Two representative along-canyon 

axis sections are shown in Figure 15. The first was during a westward flow period and the second was 

during an eastward flow period. Although the directions were opposite of each other, the magnitude of the 

net heat and salt transport for each glider transect were comparable. The net heat transport was on the 

order of 2 TW to 2.3 TW and the salt transport was on the order 0.03 Sv.
22

Figure 15. Plot of temperature and salinity as well as heat and salt fluxes for two along-canyon 

axis glider transects. 

(a) Temperature and heat flux for transect on 9/1/16. (b) Salinity and salt flux for same transect as (a). (c) 

Temperature and heat flux for transect on 9/20/16 to 9/25/16. (d) Salinity and salt flux for same transect as (c).

2.3.6 Wind-Driven Circulation

2.3.6.1 Event-Scale Winds

The NARR wind fields corresponding to the four Mackenzie plume conditions are shown in Figure 16. 

a) Temperature b) Salinity

c) Temperature d) Salinity

Heat Flux Salt Flux

Heat Flux Salt Flux

9/1-9/5 9/1-9/5

9/1-9/5 9/1-9/5

9/20-9/25 9/20-9/25

9/20-9/25 9/20-9/25
23

Figure 16. NARR daily composite of surface vector winds for the Mackenzie Trough region. 

The color indicates wind speed (0–18 m/s). The four time periods correspond to the four satellite images shown in 

Figure 12. For each time period, the winds are blowing from a different direction.

The plume (Figure 16, August 28, 2016) was observed to be heading almost straight offshore during a 

period of oscillating winds but predominantly southeasterly (upwelling favorable) with the daily average 

wind speed of 10 m/s near the trough. The glider detected a thin layer of river water (~5 m thick) on the 

western side of the trough, which is consistent with what the satellite image show. Conversely, during a 

period of northwesterly winds (Figure 16, September 8, 2016) with wind speeds of 6–7 m/s, the plume 

was advected shoreward while at the same time cooled and deepened the surface mixed layer. While the 

plume water was seen on two sides of the trough, very little plume water was found in the central portion 

of the trough. The eastward flow configuration of the plume (Figure 16, September 19, 2016) was seen 

during a period of strong westerly winds with wind speeds of 10–12 m/s. This wind produced a narrower 

plume that is advected to the east. A patch of plume is clearly seen just southeast of Herschel Island. 

During this period of westerly winds, the mixed layer substantially deepened once again. The westward 

flow configuration of the plume (Figure 16, October 2, 2016) had strong northeast winds of 10–13 m/s. 

Although the river plume water was clearly seen in the satellite RGB data, the glider data was 

inconclusive during this time.

Eastward flow 

plume configuration

Offshore flow plume 

configuration

Shoreward flow 

plume configuration

Westward flow 

plume configuration
24

2.3.6.2 Two Circulation Regimes in the Mackenzie Trough

Looking closely at the glider depth-averaged velocities, we found that the circulation in the region can be 

classified into two general flow regimes: eastward flow and westward flow. Figure 17 shows examples of 

each flow regime with glider tracks (blue) and estimates of the depth-averaged velocities (red arrows) 

overlaid on sea surface height (colormap) and HYCOM daily depth-averaged currents (black arrows). By 

visual inspection, we see that the glider’s depth-averaged velocity estimates are largely consistent with 

depth-averaged velocities from HYCOM, especially during eastward flow regimes. HYCOM can also 

capture westward flow regimes but the modeled velocities tend to be weaker than the measured velocities. 

In terms of the flow on the continental shelves, we see that eastward along-shelf transport is correlated 

with sea level setup at the coast, while the sea level appears basically flat in the model during westward 

flow regimes. This basic data-model comparison gives us some confidence in using HYCOM to 

characterize the flow field in a larger spatial and temporal context.

Figure 17. Glider path (blue) and glider estimated depth-averaged velocities (red arrows) overlaid 

on top of HYCOM sea surface height field and depth-averaged currents (upper 200 m of the water 

column).

2.3.6.3 Hydrographic Response to Eastward and Westward Transport

The water column responses for the two circulation regimes outlined in the previous section are sharply 

different, especially during periods of strong along-shelf transport (Figure 18). Eastward flow is 

associated with westerly winds and high sea level setup at the coast. Although the winds during 

September 21–25 were variable, it followed a period of strong westerly winds that likely setup the 

9/1/16 - 9/5/16 10/2/16 - 10/6/16

9/21/16 - 9/25/16

Eastward Flow Eastward Flow

Westward Flow Westward Flow

9/18/16 - 9/20/16
25

observed downwelling response. The pycnocline at a depth of 30 m was depressed near the head of the 

trough to a depth of 60 m. Only surface shelf water with salinity greater than 27 psu was seen at the head 

of the Mackenzie Trough. Mackenzie River water was not observed after a period of eastward flow driven 

by downwelling, as expected. Westward flow is associated with strong easterly winds and low or flat sea 

level setup at the coast. Strong easterly upwelling-favorable winds occurred during the October 2–5 

transect. This wind condition led to the upwelling of cold (< 0 °C) and salty (> 31 psu) Pacific water onto 

the continental shelf to the west of Mackenzie Trough. The upwelling set up a very sharp density front 

across the shelfbreak. The glider measured depth-averaged velocity at the density front was over 50 cm/s. 

There is a hint of fresh shelf water landward of the upwelled Pacific water on the shelf. The glider did not 

go far enough landward to capture the coastal plume that was presumably on the shelf.

Figure 18. Cross-shelf glider sections of temperature and salinity showing the hydrographic 

responses during strong eastward flow (left panel) and strong westward flow (right panel) 

conditions.

2.3.6.4 Inter-Annual Variability of Wind and Circulation

Extending the analysis of event-scale circulation patterns in the eastern Beaufort Sea, we proceeded to 

analyze the seasonal scale wind forcing and the circulation pattern for the entire Beaufort and Chukchi 

Sea for open water season in the summer. We focused on the peak open water month of September. 

Monthly composites of surface winds from NARR show that there is considerable year to year variability 

in terms of the wind pattern, direction, and strength. For example, during September of 2011 (Figure 19, 

Oct. 2-5, 2016

Oct. 2-5, 2016

Temperature

Salinity

Sep. 21-25, 2016

Sep. 21-25, 2016

Temperature

Salinity
26

left column), the average wind in the Chukchi and Beaufort shelves was strongly easterly with wind speed 

more than 5 m/s. The monthly averaged HYCOM depth-averaged current for the same period shows that 

flow along the Beaufort shelfbreak, slope, and the Mackenzie Trough regions are all directed westward. 

In contrast, the average winds in September 2016 were moderately westerly with wind speeds of 3–4 m/s 

(Figure 19, right column). During this period, the HYCOM flow showed a well-developed Alaskan 

Coastal Current at Barrow Canyon. An eastward flowing coastal current stretches from the Chukchi shelf 

to Mackenzie Trough and into Amundsen Gulf. If we assume an advection speed of 0.1 m/s for 

Mackenzie plume water then, depending on the average winds over the course of a month, the plume 

water could end up in either the Canadian Arctic Archipelago or in the Beaufort Gyre. The two scenarios 

have very different implications for how Mackenzie River water impacts the western Arctic Ocean.

Figure 19. Top panels: NARR monthly mean surface winds for September 2011 (left) and 

September 2016 (right). Bottom panels: HYCOM depth-averaged currents and sea surface heights 

for September 2011 (left) and September 2016 (right).

One other notable difference between 2016 and 2011 was the strength of the Beaufort Gyre. If we use the 

sea surface height field as a proxy for the gyre strength, then the anticyclonic circulation around the gyre 

is much stronger in 2011. This is likely a direct result of the large-scale wind field as the winds in 

September 2011 September 2016
27

September 2011 strengthened the anticyclonic gyre circulation, while the winds in September 2016 were 

in the opposite direction of the gyre circulation.

The climatological monthly average wind fields for the Chukchi and Beaufort Seas during the high 

discharge open water season are shown in Figure 20. In general, the climatological winds for each month 

are almost always easterly. On an annual cycle, the wind is weakest in August, which is also when we 

expect the eastward coastal transport to be strongest, and strongest in November. For September, the 

average winds over most of Chukchi and Beaufort shelves are weakly easterly (2–3 m/s). Although this is 

in an upwelling-favorable direction, the strength may not be enough to reverse the direction of the 

eastward flowing coastal current. To address the question of climatological circulation for the summer 

months, a more in-depth analysis of long-term HYCOM reanalysis would be needed.

Figure 20. Climatological NARR winds for (a) July, (b) August, (c) September, and (d) October.

2.3.6.5 Multi-Year Variability of Winds and Circulation in the Western Arctic

On the inter-annual and multi-year timescales, we found a long-term variability of the seasonal winds in 

the western Arctic. For example, in the most recent years from 2012 to 2017, the winds in the Chukchi 

and Beaufort shelves, averaged for the entire summer, are weakly easterly with an average speed of 2 m/s. 

On the other hand, during the period from 2005 to 2011, the average summertime winds are much 

stronger easterlies with speeds up to 5 m/s. If we compare with the period from 2000 to 2004, the average 

summertime winds are nearly zero, averaging around 1 m/s.

a. b.

c. d.
28

Based on these observations, we think that during the years when the average summertime winds are 

strongly easterly (i.e., 2005–2011), most of the Mackenzie River water would end up being advected 

westward and eventually end up in the Beaufort Gyre, adding to the gyre’s freshwater supply and 

potentially being trapped in the Arctic for 4–14 years (Figure 21; Bauch et al. 1995, Chen et al. 2008,

Ekwurzel et al. 2001). On the other hand, during weak wind years, most of the Mackenzie River water 

would flow eastward into the Canadian Arctic Archipelago and exit the Arctic much faster, likely in the 

order of just a couple of years (Fichot et al. 2013).

Figure 21. Average NARR surface summer (July–October) winds for (a) 2012–2017, (b) 2005–2011, 

(c) 2000–2004. (d) An illustration of the major currents in the Chukchi and Beaufort Seas (adopted 

from Schulze et al. 2013). 

The red arrow indicates the likely direction of the shelfbreak boundary current during times of strong easterly winds. 

2.4 Discussion

The hypotheses tested during the AUV glider component included:

a. b.

c. d.
29

• The Mackenzie River plume strongly affects the stratification and bio-optical properties of the 

surface mixed layer on both Canadian and US continental shelves. This is discussed in sections 

2.3.2, 2.3.3, and 2.3.4. 

• River-shelf-basin exchange is strongly affected by seasonal heating and cooling, wind-driven 

advection, and interaction with shelfbreak frontal currents. This is discussed is sections 2.3.5 and 

2.3.6. 

• In the absence of strong wind forcing, buoyancy-driven shelf flow and the shelfbreak jet advects 

fresh Mackenzie River water eastward toward the Amundsen Gulf. Under moderate to strong 

easterly winds, however, the Mackenzie River plume is advected westward toward the Alaskan 

Beaufort Sea. This is discussed in section 2.3.6.

• The Mackenzie River plume and wind forcing vary on time scale of 1 to 2 weeks driven by 

regional weather and variability of shelf and shelfbreak circulation. This is discussed in section 

2.3.6. 

2.4.1 Connection Between Beaufort Shelf and Beaufort Gyre

It is worth highlighting the ephemeral nature of the coastal and shelfbreak circulation in the Beaufort Sea. 

Although the anticyclonic Beaufort Gyre is a persistent feature, which may strengthen or weaken over the 

course of multiple years, the shelfbreak jet and the coastal current can change strength and direction on 

event time scales of days to weeks. Under strong easterly winds, the shelf current, shelfbreak jet, and the 

Beaufort Gyre all flow in the same direction. Based on the HYCOM model output, it is not clear whether 

the gyre circulation and the shelfbreak boundary current merge as one or whether they maintain their 

separate identities.

During one part of the MARES glider deployment (October 2–5, 2016), the strong westward current at 

the shelfbreak, formed directly as a result of shelfbreak upwelling, had its own well-defined structure with 

peak velocity right at the shelfbreak. However, at other times, the shelfbreak jet was not well defined, just 

a westward transport across the entire glider cross-shelfbreak transect (September 5–7, 11–16). Although

we cannot definitively address this issue with the current dataset, we hypothesize that, depending on the 

forcing condition, the Beaufort shelfbreak jet is a separate flow feature at times, or it can be part of the 

Beaufort Gyre pressed southward against the continental slope at other times. The difference depends on 

local zonal wind shear and the magnitude of shelfbreak upwelling. 

2.4.2 Multi-Year Variability of Zonal Winds in the Beaufort Sea

There is multi-year variability to the summertime wind pattern in the Chukchi and Beaufort Sea. This can 

be seen when considering the wind data observed during the glider deployment and the other time periods 

discussed above into a multi-year and even multi-decade context (Figure 22). Overall, the data show that 

the summertime zonally averaged wind speed for the Chukchi-Beaufort shelf, and slope region for all 

years from 1948–2004 and 2012–2017 reached a maximum speed of approximately 10 m/s (average wind 

speed of 4 m/s) and have been predominantly easterly winds. This pattern held true except for the period 

from 2005 to 2011 when the average easterly zonal wind speed was 10 ± 5 m/s. This is a substantial

departure from the climatological mean and would likely have driven an anomalous westward flow along 

the Chukchi and Beaufort shelves and shelfbreak during those years.
30

Figure 22. Summertime zonally averaged wind speed for the Chukchi-Beaufort shelf and slope 

region (1948 to 2017 NCEP reanalysis). 

The alternating green, pink, green regions highlights the three periods considered in our temporal variability analysis.

2.4.3 Fate of the Mackenzie Plume

In the context of considering the fate of freshwater discharging into the Arctic from the Mackenzie River, 

strong and persistent westward transport could lead to advection of Mackenzie River water onto the 

Alaskan Beaufort Shelf and eventual entrainment into the Beaufort Gyre. The nominal residence time of 

water in the western Arctic is 4–14 years (Bauch et al. 1995, Chen et al. 2008, Ekwurzel et al. 2001). On 

the other hand, there is substantial transport of freshwater from the western Arctic into the Atlantic Ocean 

through the Canadian Arctic Archipelago, if a persistent westerly wind supports eastward along-shelf 

transport. In that case it is possible for Mackenzie River water to flow directly into and through the 

Canadian Arctic Archipelago along the Canadian Beaufort shelf, where it may stay for a couple of years 

before exiting the Arctic into the North Atlantic (Fichot et al. 2013). 

2.5 Conclusions

The glider component of the MARES project provided physical, biological, and chemical observations 

acquired from a moving platform and allowed for the collection of fine scale information on the 

Mackenzie River plume. The glider study complemented the ongoing mooring component in the study 

region and found that:

• Wind appears to be the main driver of shelfbreak and Mackenzie Trough circulation.

• Multi-year variability of summertime winds affects the structure of the Beaufort Gyre, shelfbreak 

boundary current, and downstream fate of Mackenzie River water.

• The shelfbreak jet and the coastal current can change strength and direction on event time scales 

of days to weeks.

• In years when the average summertime winds are strongly easterly (i.e., 2005–2011), most of the 

Mackenzie River water flows westward and eventually ends up in the Beaufort Gyre, adding to 

the gyre’s freshwater supply and potentially being trapped in the Arctic for up to 14 years. 

• During weak wind years, most of the Mackenzie River water is downwelled, flows eastward into 

the Canadian Arctic Archipelago, and exits the Arctic much faster (a couple of years).

• The summertime Chukchi and Beaufort shelfbreak jet cannot be assumed to be steady on the 

inter-annual timescale. The timeframe of 2005–2011 appears to be an exceptional period with 

stronger easterly winds (upwelling conditions with plume going westward) than any period before 

or since.
31

2.6 Limitations of the MARES Glider Survey

The MARES glider deployment collected unprecedented high resolution physical, bio-optical, and bioacoustic data in the Mackenzie Trough region during the summer open water season in 2016. The study 

was enabled by new advancement in glider technology, such as large displacement buoyancy pumps, 

hybrid thrusters, and new bio-optical and bio-acoustic sensors. At the same time, the glider program was

one part of a larger study involving ship-based sampling and moorings. 

Because of the large size of the Mackenzie Trough and the importance of mesoscale processes, it is 

impossible for a single glider to conduct a synoptic survey of the entire region. Each complete survey of 

the trough took 10–15 days, during which the circulation pattern could have changed several times (as we 

have found in this study). To overcome this sampling issue in our interpretation of the data, we divided 

the glider survey into quasi-synoptic individual transects, each 2–5 days long. We were further guided by 

the insight that the circulation is largely wind-driven. By using a combination of reanalysis wind 

modelling, data assimilative ocean modelling, and satellite remote sensing to complement the glider 

observations, we were able to reconstruct the major events and circulation regimes encountered during the 

MARES 2016 summer field season. To capture important event drivers at the appropriate temporal scales 

and thus enable true synoptic sampling using autonomous platforms, we recommend that a minimum of 

three underwater gliders be deployed simultaneously.

2.7 Future Research

2.7.1.1 Synthesis With MARES Moorings

The MARES moorings were deployed in fall of 2016 and were scheduled be re-deployed in October 

2017. An obvious synthesis effort between the glider and mooring data will be needed when the mooring 

data have been retrieved and processed. The mooring array, deployed across the western wall of the 

Mackenzie Trough, should be able to capture the temporal variability of the shelf and shelfbreak 

circulation and hydrography in detail. These data should shine light on the issue of how the circulation 

might respond to changes in wind forcing and may determine the threshold wind velocity which can

reverse the direction of the eastward flowing coastal and shelfbreak current.

2.7.1.2 Detailed Analysis of Bio-optical Data

There is a substantial amount of bio-optical and bio-acoustic data from the glider that remain to be 

analyzed in detail. The relationships between water masses, stratification, light, primary production, and 

dissolved oxygen have yet to be explored. As one example, preliminary analyses have shown evidence of 

biological heating at depth below the mixed layer. Two examples of this phenomenon are shown in the 

profile plots in Figure 23 where at depths of 20–25 m and 30–35 m, sub-surface chlorophyll maxima at 

the bottom of the pycnocline spatially correspond to positive temperature anomalies of nearly 1 °C. A 

detailed quantitative analysis of this phenomenon has yet to be completed.
32

Figure 23. Profile plot of glider temperature (red), chlorophyll-a (green), light (blue), and density 

(black) measurements for two glider transects during MARES 2016. 

Both transects were on the Beaufort shelf to the west of Mackenzie Trough in the first half of the deployment.

2.7.1.3 Data Assimilative Modeling and Model-data Comparison

Though not part of the currently funded MARES study, validation and assimilation for future processoriented high resolution numerical modeling studies would help resolve the detailed circulation and 

dynamics inside the Mackenzie Trough. A recent idealized modeling study (Machuca and Allen 2018)

has shown interesting coastal trapped waves, which affect the dynamics of canyon upwelling and 

downwelling inside the Mackenzie Trough. A comparison analysis of the glider data with the model could 

help us better understand the sub-mesoscale variabilities observed with the glider. 

Furthermore, upgrades to the Global HYCOM model with the addition of more vertical layers targeting 

the shallow continental shelf environment (GOFS 3.1 with 41 layers vs. GOFS 3.0 with 32 layers), as 

well as a detailed comparison of the HYCOM output with the glider data with hydrography in addition to 

velocity, would be highly useful. When the longer term HYCOM reanalysis product is available and 

validated, we could use the model to make regional scale heat and salt budget calculations.

Finally, changes in ice conditions and longer open water seasons and fetch have likely been affecting 

these wind-driven dynamics and possibly been accentuating the difference between these two regimes and 

their subsequent effects on circulation and plume entrainment. Given the implications for oil spill 

trajectories and potential ecological impacts of spills, it would be beneficial to couple our findings with 

regional models that include ice cover and wind forcing factors.

2.7.1.4 Lagrangian Analysis of the Mackenzie Plume

Finally, using virtual Lagrangian tools such as tracers and drifters, we could conduct long-term release 

experiments with validated models to better determine the downstream fate of Mackenzie River plume on 

a range of space and time scales.
33

3 Mooring Array

3.1 Introduction

As part of MARES, a mooring array was deployed October 5th and 6th, 2016 across the shelf-slope of the 

Canadian Beaufort Sea (Figure 24). In addition to the four MARES moorings, an inshore mooring was 

deployed for the UAF, and an offshore mooring was deployed the previous month by DFO Canada. 

Hence, the composite MARES/UAF/DFO array consists of six moorings spanning from the inner shelf

(14 m depth) to the mid-continental slope (750 m depth) This unique group of mooring provide a 

yearlong time series of the biophysical and chemical characteristics along the shelf and on to the 

continental slope, including under-ice periods, and able to capture the influence of the Mackenzie River

plume in this region. 

Figure 24. Locations of the moorings comprising the composite MARES/UAF/DFO array (see the 

legend). Also shown are the locations of the CTD stations occupied during the deployment cruise. 

The bathymetry is from the International Bathymetric Chart of the Arctic Ocean (IBCAO) version 3. 

3.2 Methods

3.2.1 Field Methods and Equipment

The CCGS Sir Wilfrid Laurier was loaded on June 19, 2016 in Victoria, B.C., Canada, with all the 

necessary mooring equipment. On September 20, 2016, the ASL mooring technician boarded the ship in 

Mackenzie 

Trough

Herschel 

Island
34

Cambridge Bay, enabling him to locate, prepare, and program most of the ASL and WHOI mooring 

instrumentation prior to the beginning of the MARES segment of the cruise. This included performing the 

compass spins of the Acoustic Doppler Current Profilers (ADCPs). All of the other ASL and WHOI 

equipment checked out properly. The rest of the MARES team embarked the ship at Herschel Island via 

helicopter on October 3, and science operations began the morning of October 4.

First, the ship collected bathymetric data at the inshore end of the line to determine the location of the 

UAF inner-shelf mooring. Following this, the conductivity-temperature-depth (CTD)/water sample 

section was carried out, consisting of 14 stations along the mooring line (Figure 24), five of which 

included water sampling. The CTD section included water samples for inorganic nutrients, dissolved 

inorganic carbon (DIC), and carbon characterization of suspended sediments. During this time, the last of 

the mooring instrumentation was prepped, and the assembly of the mooring components started.

On October 5, 2016, the two ASL moorings (M4 and M3) were deployed along with the offshore WHOI 

mooring (M2). On October 6, 2016, the MARES glider was successfully recovered (see Section 2), and 

the WHOI mid-shelf mooring (M1) and UAF inner-shelf tripod were deployed (Figure 24; Table 1). 

Except during the deployment of the M3 and M4 moorings, when the sea state was marginal with 10–15 

knot winds, the weather throughout the MARES segment of the cruise was ideal: light winds, calm seas, 

and good visibility. For the ASL and WHOI tall moorings, an acoustic survey was done after the 

deployments to precisely determine their locations (the tripods were lowered to the seafloor, hence no 

survey was required). 

The instrumentation on each mooring is listed in Table 2 and shown schematically in the vertical plane in 

Figure 25–Figure 27. For the most part, the point temperature/salinity/pressure instruments (MicroCat 

T/S/P) record data every 15 minutes, the WHOI ADCPs sample hourly, the ASL Long Ranger ADCPs 

sample every 5 minutes, and the ASL’s Quartermasters sample every 2 minutes. The moored profiler

collects a vertical trace every 4 hours. This configuration enabled us to construct vertical sections of 

hydrographic properties and velocity numerous times per day. Both the zooplankton/fish recorders and 

point chemical sensors sample every hour, and the upward-looking sonars record ice drafts every few 

minutes. Finally, the passive acoustic marine mammal recorder samples 20 minutes out of every hour.
35

Figure 25. WHOI moorings M1 and M2.
36

Figure 26. Mooring M3 and M4 (ASL).
37

Figure 27. Instrumentation on the UAF, WHOI, and ASL moorings.
38

Table 1. UAF, WHOI, and ASL moorings deployed on the CCGS Sir Wilfrid Laurier cruise.

Name Latitude Longitude Bottom depth 

(m) Date Position method

UAF 69 36.426 139 42.925 14 10/06/2016 Anchor splash

M1 (WHOI) 69 46.235 139 15.286 40 10/06/2016 Anchor splash

M2 (WHOI) 69 54.475 138 59.925 175 10/05/2016 Surveyed position

M3 (ASL-300) 70 2.909 138 47.691 300 10/05/2016 Surveyed position

M4 (ASL-440) 70 15.101 138 47.626 440 10/05/2016 Surveyed position

Table 2. List of the instrumentation contained on the WHOI and ASL moorings.

Mooring Deploy depth (m) Instrument

M1 16 MicroCat T/S/P

22 MicroCat T/S/P

28 MicroCat T/S/P

39 MIR logger

39 SUNA nitrate

39 SAMI pCO2 sensor

39 SAMI battery

39 Upward-facing 300 kHz ADCP

M2 20 MicroCat T/S/P

26 MicroCat T/S/P

31 MicroCat T/S/P

35 Upward Looking Sonar (ULS)

35 Upward-facing 300 kHz ADCP

35 MIR data logger

39 SAMI pCO2 sensor

39 SUNA nitrate sensor

39 SUNA Battery

39 MicroCat T/S/P

- MMP T/S/P/O2 + fluorescence, PAR, turbidity

162.5 Upward-facing 300 kHz ADCP

162.5 MicroCat T/S/P

166 AURAL whale recorder

M3 50 IPS 5 Ice Profiling Sonar

50 SBE Temperature Sensor

60 Acoustic Zooplankton Fish Profiler (AZFP)

100 Upward-facing 150 kHz ADCP-QM

130 SBE

190 SBE

250 SBE

280 Upward-facing 75 kHz ADCP-LR

300 Acoustic Zooplankton Fish Profiler (AZFP)

302 ORE PORT

39 MicroCat T/S/P

M4 50 IPS 5 Ice Profiling Sonar

50 SBE

100 Upward-facing 150 kHz ADCP-QM

130 SBE

190 SBE
39

Mooring Deploy depth (m) Instrument

250 SBE

330 Upward-facing 75 kHz ADCP-LR

428 ORE PORT

3.3 Results and Conclusions

The 2016 mooring deployment program was successful in deploying the four MARES moorings and the 

UAF mooring and collecting data via CTD casts and water samples. All mooring sensors were tested and 

deemed functional. The moorings remained in place until a recovery and redeploy cruise undertaken in

the fall of 2017. 

The CTD data was successfully collected at 14 stations along the mooring line, and potential temperature 

and salinity profiles were calculated (Figure 28, Figure 29). The thermocline and halocline were 

shallower than 50 m at all the stations, but comparatively shallower over the shelf. The layer of fresher 

and warmer surface waters were indicative of a freshwater input, probably from the Mackenzie River, 

given the samples were taken during the ice-free season long after ice melt. 

At five of the CTD stations, water sampling was also completed (Figure 28). Measurements of 

temperature, salinity, DIC, nutrients, and total alkalinity were collected at varying depths at the M1, M2, 

M3, and M4 mooring locations, as well as at a midpoint along the line (Figure 30). 
40

Figure 28. Vertical section of potential temperature (oC, color), as estimated from the CTD casts,

overlain by potential density (kg/m3, contours), occupied during the deployment cruise. 

The black circles denote water sample locations. The CTD station numbers are listed at the top. The bottom 

topography is from the CCGS Sir Wilfrid Laurier's echosounder.
41

Figure 29. Vertical section of potential salinity, as estimated from the CTD casts, and locations of 

the UAF, WHOI, and ASL moorings. 

The CTD station numbers are listed at the top. The bottom topography is from the CCGS Sir Wilfrid Laurier's

echosounder. 
42

Figure 30. Profiles of water data collected at the mooring locations and at the midpoint along the 

MARES mooring line in October 2016 (note different y-axis scales for each row of data).
43

4 Linking Organic Carbon Sources with Meiofauna Abundance and 

Diversity

4.1 Introduction

Linking organic carbon sources with meiofauna abundance and diversity across the coastal shelf of the 

Mackenzie Delta involved sediment sampling, isotope and fatty acid analysis, and taxonomic 

identification. The Mackenzie continental shelf spans the northern part of the Canadian Arctic Ocean 

between the Amundsen Gulf on the east and the Mackenzie Trough to the west (Rachold et al. 2004). Ice 

typically begins to form on the shelf in mid-October and the delta, and nearshore areas stay ice covered 

until the spring break up in mid-May (O’Brien et al. 2006). Across the Mackenzie shelf and in the 

adjacent Beaufort Sea, the Mackenzie River dominates the supply of particulate organic carbon (POC) to 

the sediments with inputs of 2.1 Mt/yr, making it the largest sediment load from river input in the Arctic 

Ocean (Macdonald et al. 1998). About 70% of the freshwater discharges occur between May and 

September with the spring freshet, with 90% of the particulate flux occurring in June, July, and August 

(Yunker et al. 1995). Autochthonous primary production in the delta and nearby shelf is estimated to add 

at least an additional 3.3 Mt/yr of POC (Macdonald et al. 1998). Carbon preservation estimates in the 

region are limited but suggest that up to 97% of new production may be recycled and never reach the 

underlying sediments, while 60% of the POC from the terrestrial dominated Mackenzie River outflow, 

reaches sediments to be retained (Yunker et al. 1995, 2005). Sediments in the northern Beaufort Sea have 

been found to be dominated by a mixture of refractory marine and terrigenous carbon (Magen et al. 

2010). A detailed comparison of carbon sources across the eastern Beaufort shelf using multiple methods 

found terrestrial carbon accounted for 11% to 44% of sedimentary organic matter, indicating that landderived organic matter can play a substantial role in carbon dynamics in this region (Belicka and Harvey

2009). On the Beaufort shelf, eddies also play an important role in moving these sources of particulate 

organics, mixing old and newer materials. Data from stations at the eddy influenced shelf edge were 

found to be dominated by biogenic organic matter (O’Brien et al. 2013).

The goal of this study component was to understand the linkages between the flux of multiple sources of 

organic matter reaching bottom sediments, its recycling by the benthic community, and the impact on the 

community it supports. To accomplish this, four stations transecting the Mackenzie shelf and located 

directly below the four MARES moorings (see Section 3) were sampled for water column particles and 

sediments via box core during the mooring deployments (Figure 24). An additional station, located midway between the moorings, was sampled for water column particles only. Sediment sampling started at 

the 40 m isobath and ended at the approximate 440 m isobath. Sediments were analyzed for organic 

carbon and grain size as well as a suite of organic biomarkers combined with identification of benthic 

meiofaunal community structure. The analysis of amino acids, POC, and fatty acid and sterol biomarkers 

were performed and compared to meiobenthic diversity and abundance. 

4.2 Methods

4.2.1 Sampling Locations 

Field sampling was performed on the CCGS Sir Wilfrid Laurier in the Fall (October) of 2016 as part of 

the MARES mooring deployment cruise. Station locations are shown in Figure 24 and Table 3.
44

Table 3. Sampling locations for water and sediment collections.

Station Latitude Longitude Date sampled Sample type

M1 

(CTD station 4) 69 46.24 N 139 15.56 W Oct 04 2016 Water/Sediments

M2 

(CTD station 7) 69 54.43 N 138 59.81 W Oct 04 2016 Water/Sediments

Midpoint 

(CTD station 9) 69 57.90 N 138 52.62 W Oct 05 2016 Water only

M3 

(CTD station 11) 70 02.92 N 138 47.62 W Oct 05 2016 Water/Sediments

M4 

(CTD station 14) 70 15.09 N 138 47.65 W Oct 05 2016 Water/Sediments

4.2.2 Water Column Particles

Particles were collected using Niskin bottle samplers attached to a rosette and deployed with a Seabird 

CTD to collect water column profile data on the downcast (Table 4). Water samples were taken at two 

depths: near the bottom at approximately 1 m above the sediment surface, as well as at the fluorescencemaximum of each station. The particle fraction was obtained by filtration through pre-combusted 

(400 °C) Whatman glass fiber filter (GF/F, nominal pore size 0.7μm) and immediately frozen to -20 °C 

until analysis. Samples were also collected for nutrient analysis, shown in Section 3. 

Table 4. Water column sample collection and depths (m) at each station.

Sample collected M1

(CTD station 4)

M2

(CTD station 7)

Midpoint

(CTD station 9)

M3

(CTD station 11)

M4

(CTD station 14)

POC 37.7 172.5 - 299.3 439.6

POC 37.7 172.5 - 299.3 439.6

POC 37.7 172.5 - 299.3 439.6

DIC and Nutrients 37.7 172.5 211.9 299.3 439.6

DIC and Nutrients 25.6 101.1 100.9 201.1 201.2

POC 10.8 20.6 - 35.6 40.4

POC 10.8 20.6 - 35.6 40.4

POC 10.8 20.6 - 35.6 40.4

DIC and Nutrients 20.4 39.8 39.2 100.2 100.8

DIC and Nutrients 15.8 20.6 25.3 45.6 40.4

DIC and Nutrients 10.8 10.7 10.7 25.5 25.6

DIC and Nutrients 1.7 1.7 3.8 3 1.6

4.2.3 Sediments

Surface sediment (0–10 cm) samples were collected (Table 5) using a 0.25 m2 stainless steel box core 

(KC–Denmark). Upon retrieval, the undisturbed interface water and outer 2 cm of the core were removed 

and the rest of box core sliced into 1 cm horizontal increments to 10 cm using a slicing table. The 1 cm 

slices were homogenized, and separate samples were taken for meiofaunal abundance and organic matter 

characterization. Samplers were sliced in a closed van and otherwise protected from stack smoke, grease 

drips from winches and wire, and other potential contamination during preparation. Contamination blanks 
45

for deck and laboratory processing of samples were collected in parallel with samples to be analyzed for 

biology and chemistry. Sediments for organic analysis were stored in pre-cleaned plastic I-Chem jars with 

Teflon-lined screw-cap lids and immediately frozen. Prior to grain size and organic analysis, sediments at 

each depth increment were homogenized and lyophilized, and samples for organic analysis were then 

taken from freeze dried sediments only. Meiofaunal counts were performed from whole sediment samples 

preserved in 5% formalin. 

Table 5. Locations of sediment collections for organic and meiofaunal analysis

Site Latitude Longitude Bottom depth 

(m) Date Comment

M4 70 15.1011 N 138 47.6262 W 440 5-Oct-16

M3 70 02.9093 N 138 47.6911 W 300 5-Oct-16

M2 69 54.4778 N 138 59.9251 W 175 5-Oct-16

M1 69 46.1113 N 139 15.1418 W 40 6-Oct-16

UAF 69 36.4259 N 139 42.9254 W 14 6-Oct-16 No sample,

gravel at seabed

4.2.4 Total Organic Carbon

Total organic carbon and particulate nitrogen was determined in lyophilized and homogenized sediments 

using standard combustion methods (Zimmerman et al. 1997) after removal of carbonates by treatment 

with 1 M HCl and evaporation to dryness. 

4.2.5 Grain Size 

Particles size distributions of the sediment from the four stations along the transect (Figure 24) were 

determined from lyophilized sediments, which were homogenized and subsampled. Following removal of 

organic materials with aqueous hypochlorite (5%), particles distributions were determined using standard 

methods with a Malvern sediment grain size instrument (Sperazza et al. 2004).

4.2.6 Meiofaunal Abundance and Diversity

Samples in 1 cm intervals through the first 5 cm of the sediment column were preserved using 5% 

formaldehyde and then analyzed for meiofaunal diversity and abundance. Upon receiving samples in the 

laboratory, they were transferred from formalin to ethanol and processed on a 45μm mesh screen to 

remove sediment but retain organisms. Once samples were in ethanol they were stained using Rose 

Bengal, a vital dye that stains protein to facilitate sorting of organisms from the sediment. Samples were 

sorted to major taxonomic group and then identified to the lowest practical taxonomic level following a 

two-day staining process. It was not feasible to obtain biomass by weighing meiofaunal organisms,

because the organisms were sparse and the potential for loss of organisms during the weighing process 

was high. Additionally, this program specified retaining specimens for future studies and comparison. As 

a result, wet weight and dry weight biomass for major taxonomic groups were calculated based on 

measurements obtained in previously published literature.

4.2.7 Organic Biomarkers

4.2.7.1 Amino Acids

For amino acids, both particulate organic matter (POM) and sediments were hydrolyzed at 110 °C for 16 

hours in 6 N HCl. After hydrolysis, sediments and particle samples were decanted, leaving the 
46

supernatant for analysis. Samples hydrolyzed for amino acids were then dried under ultrapure liquid 

nitrogen and rinsed three times with nanopure water. Samples were subsequently spiked with the set of 

deuterated internal standards representative of each functional group present in amino acids. The analysis 

was performed using liquid chromatography-mass spectrometry (LC-MS) with no derivatization step;

instead, ion pairing mobile phases and retention time-based mass selection were used. For analysis, an 

Agilent 1290 Infinity LC was used in connection to a bonded silica C18 Dionex Acclaim Polar advantage

Rapid Separation Liquid Chromatography (RSLC) column (2.2 μm, 120 A x 150 mm) for 

chromatographic separation and paired with a Thermo Scientific Orbitrap XL mass spectrometer. A guard 

column was added in line having the same column as the analytical column but with a 5μm particle size. 

The gradient used for mobile phase A included the ion pairing reagent (0.4% of phase) HFBA, formic 

acid (0.02% of phase) and LC-MS grade water. Mobile phase B included formic acid (0.1% of phase) in 

acetonitrile. The gradient program, modified from Piraud et al. (2005) utilized 100% mobile phase A from 

0 to 1 minutes, 85% A from 1–6 minutes, 85% to 75% between 6 to 9 minutes, and 75% mobile phase A 

from 9–15 minutes; from 15–16 minutes the gradient was set to an isocratic state of 100% mobile phase 

A. All amino acids were observed over a 16-minute window, followed by a 15-minute isocratic 

recondition of the column with a 100% mobile phase A. 

The LC was integrated with a Thermo Scientific Orbitrap XL via an ESI interface for structural analysis. 

Data was acquired and processed in Xcalibur software (Thermo Scientific, Rockford, IL) at a scan range 

of 50–300 m/z using positive ion mode using a scan. The collision energy was kept constant through the 

entire run at 35 V with collision-induced dissociation (CID) activation in the primary scan and a scan 

cycle (resolution) of 30,000. The ESI source parameters included a capillary temperature of 275 o

C, spray 

voltage of 3.5 V, and capillary voltage of 2.5 V. All ESI source parameters were tuned and maximized 

before sample runs. 

4.2.7.2 Calibration and Standards

Amino acid concentrations were calibrated using an internal standard/external standard paired set to 

provide coverage over the major functional groups of amino acids being determined. Each amino acid 

used an individual calibration curve that was normalized to one of the five chosen internal standards 

based on the functional groups. Most amino acids were calibrated from a commercial set of 30 known 

amino acids (Phenomenex) plus internal standards which include L-Aspartic-2,3,3,d3 acid, L-cystine2,2’,3,3,3’,3’-d6, DL-Lysine-4,4,5,5-d4, L-Leucine-5,5,5-d3, L-Phenylalanine ring-D5. The final sample 

concentrations were determined based on the ratio of amino acid peak area to the internal standard peak 

area. In total, 45 amino acids were calibrated and identified with mass values based on retention times and 

published literature mass spectrums for each amino acid.

4.2.8 Lipid Markers

4.2.8.1 Extraction

Surface sediment increments (0–1 cm) were thoroughly homogenized prior to chemical analysis. 

Lyophilized sediment was transferred to Green Chem glass vessels with Teflon screw-cap lids and two 

internal standards added prior to extraction (N-nonadecanoic acid and 5α-cholestane) for calculation of 

recoveries and concentrations of polar and neutral products respectively. Sediments were extracted with a 

ratio of 1:1 hexane: acetone (35 ml) at 80 °C for 30 minutes and stirred on the high setting using a MARS 

microwave assisted extraction system (CEM Corp., Matthews, NC) operating at 1,200 W (refinement of 

EPA Method 3546). After extraction, vessels were cooled to room temperature before being opened. The 

supernatant was initially filtered through pre-cleaned and combusted glass wool and then combined with 

2–4 ml hexane: acetone (1:1) rinses of the extraction vessel containing the sample. Sediment extracts 

were concentrated to 3 ml using rotary evaporation and then further hydrolyzed in 0.5 NaOH to partition 
47

neutral and polar products (e.g., Belicka et al. 2009). Labware (glass or Teflon) used in the extraction 

process was washed in Alconox, soaked in RBS-35 detergent and then 15% HCl each for 24 hr, and 

rinsed three times with reverse osmosis (RO) or ultraviolet (UV) Nanopure water after each washing step. 

Glassware was dried and then combusted at 450 °C for 4 hours to remove any possibility of remaining 

organics. A procedural blank was prepared and analyzed in parallel with each round of samples extracted. 

4.2.8.2 Structural Characterization

Neutral and polar lipid markers were analyzed by capillary gas chromatography (GC) with an Agilent 

6890 system coupled to an Agilent 5973 Network Mass Selective (MS) Detector operated in electron 

ionization mode following previously described procedures for structural analysis of lipids (e.g., Belicka 

et al. 2009). The GC-MS system was equipped with a J&W Scientific DB-5MS fused silica column 

(30 m, 0.25 mm id, 0.25 film thickness) and operated in full scan mode with acquisition over 100–600 

amu. Samples were injected in splitless mode at an initial oven temperature of 50 °C and an injector 

temperature of 250 °C with helium as the carrier gas. The oven temperature was ramped at 15 °C/min to 

120 °C and then 3.5 °C/min to 300 °C before holding at 300 °C for 10 minutes. Calibration and tuning of 

the mass spectrometer was carried out after each set of 10 samples using perfluorotributylamine (PFTBA) 

as the calibrant. For each round of 12 samples, one procedural blank was prepared to monitor potential 

contamination resulting from glassware, solvents, and processing procedures.

4.3 Results

4.3.1 Water Structure Across the Shelf

Water samples collected from the four Mackenzie shelf station locations displayed a fresh and warm nearsurface layer with increased salinity at depth (near-bottom) (Figure 31–Figure 34). The halocline varied 

with each station but occurred in the first 50 db (50 m) of the water column. This suggested that surface 

waters receive a substantial input of fresher water associated with river runoff as there was no ice during 

the time samples were collected.

Sub-surface chlorophyll maxima were observed at all stations in the top 35 m, but the fluorescence levels 

at Mooring M3 and M4 were nearly twice those as compared to stations M1 and M2. Fluorescence was 

closely related to the thermocline, and decreasing rapidly after the halocline. 
48

Figure 31. Physical parameters of station M1 at the time of sampling. 

Salinity, temperature, and fluorescence are reported through the water column. Sampling depths for POM at the 

chlorophyll maximum and bottom of water column are reported by the green and black triangles respectively.
49

Figure 32. Physical parameters of station M2 at the time of sampling. 

Salinity, temperature, and fluorescence are reported through the water column. Sampling depths for POM at the 

chlorophyll maximum and bottom of water column are reported by the green and black triangles respectively.
50

Figure 33. Physical parameters of station M3 at the time of sampling. 

Salinity, temperature, and fluorescence are reported through the water column. Sampling depths for POM at the 

chlorophyll maximum and bottom of water column are reported by the green and black triangles respectively.
51

Figure 34. Physical parameters of station M4 at the time of sampling. 

Salinity, temperature, and fluorescence are reported through the water column. Sampling depths for POM at the 

chlorophyll maximum and bottom of water column are reported by the green and black triangles respectively.

4.3.2 Total Carbon and Grain Size

Sediments collected along the cross-shelf transect were consistent in both organic carbon content (Table 

6) and grain size (Figure 35). Levels of surface sediment organic carbon were below 2% of the dry weight 

at the four stations, with station M2 having the highest value at 1.6%. In the water column, POC values at 

fluorescence maximum varied with station. M4 (deepest location) had the lowest value of POC at 

0.036 mg/L, while the highest values in the water column were seen at station M2 (mid-shelf) with 

0.062 mg/L, and at the bottom at M4 with 0.077 mg/L (Table 6). Station M3 also had high POC results 

when compared to station M4, with nearly 50% more POC (0.058 mg/L) at the fluorescence maxima. 
52

Table 6. Organic carbon content of all samples from the water column and surface sediments. 

Sample Type Depth M1 M2 M3 M4

Water column POC 

(mg/L)

10 m 0.046 - - -

20 m - 0.062 - -

35 m - - 0.053 0.036

Bottom 0.058 0.058 0.050 0.077

Surface sediments organic carbon 

(% carbon dry weight) 0-1 cm 1.1% 1.6% 1.4% 1.3%

Grain size was overall uniform along the cross-shelf transect (Figure 35). Mineral fractions peaked 

between 3–5 μm in the clay size range for surface sediments. Station M4 was also examined at horizon to 

5 cm and had consistent mineral fractions, highlighting the extensive mixing that materials must undergo 

prior to sediment deposition.

Figure 35. Grain size across the four shelf stations of the Mackenzie shelf transect.

Overall sediments at surface and at depth showed a uniform grain size distribution suggesting little sorting prior to 

transport and deposition.

4.3.3 Organic Markers

Samples of POM and sediments along the Mackenzie shelf basin yielded variable concentrations of 

hydrolysable amino acids. Surface sediments at station M1 have the lowest levels of THAA μg/OC across 

the four stations, while station M2 has the highest (Figure 36). In the water column at chlorophyll 

maximum, amino acids concentrations increased from inshore to offshore, with station M4 clearly 

showing the highest levels (Figure 36). The range of amino acids contributing to the total organic carbon 
53

present ranged from 0.02% amino acids (bottom water POM station M2) to a maximum of 3.5% in 

particles at the M4 fluorescence maximum depth. 

Amino acid composition varied across stations (Figure 37). M4 had more hydroxyproline than station 

M1, while M1 had tyrosine and M4 did not. Glutamic acid and lysine were consistently the most 

abundant amino acids in the sediments at the four stations but had its highest contribution at M2. Glycine 

was observed everywhere in the sediments but absent in the water column. In the particulate matter, 

glutamic acid and gamma aminobutyric acid (GABA) were the most abundant amino acids. GABA

showed highest levels furthest from shore (M4) (Figure 38). 

Figure 36. Measure of total hydrolysable amino acids (THAA) normalized to organic carbon

microgram in particles and sediments across the Mackenzie shelf. 

Samples depths for the chlorophyll maximum and bottom particles (POM) are shown in Figure 31. Measure of THAA 

in surface sediment were defined as the 0–1 cm horizon. 
54

Figure 37. Distribution of individual amino acids in each sample represented in a unit of relative 

abundance, percent of each amino acid that contributes toward the total sum of all amino acids in 

that sample. 

Samples gathered at the AIM site, which was not part of this study, are shown to the left with a black dashed line, as 

a representative pelagic site (AIM site is located at 75 05.79 N, 168 03.54 W). Those labeled ‘sed’ represent surface 

sediment samples from the first 1 cm of the sediment. Those marked with a depth represent the sampled chlorophyll 

maximum POM. Those marked with bottom were sampled in the water column right above the surface of the 

sediments. Amino acids not displayed in the top most abundant 12 amino acids were summed together in the 

category of ‘sum of others.’ The inserted plots on the bottom represent an example of what amino acids were seen in 

small abundances in both sediment samples, AIM sediments and water column POM (M2 20 m), which are 

representative of the sum of others category.
55

Figure 38. A) The % GABA as fraction of total amino acids in surface sediments across the 

MARES transect plus the AIM pelagic site for comparison. B) The % GABA as fraction of amino 

acids in POM collected at the fluorescence maximum at available water column sites. 

Error bars in this plot represent the standard deviation of analytical replicates.

4.3.4 Fatty Acids and Sterol Biomarkers

Fatty acids detected were grouped depending on their structure and are presented in Figure 39. Phytol, a 

side chain of chlorophyll and sterols, showed an increase in marine related biomarkers in the sediment at 

mid-shelf stations. Sterols linked to terrestrial sources, were highest at station M1 as expected. The sum 

of fatty acids was highest at station M2 and M3 at 2 mg/g dry weight as compared to half that quantity 

seen at station M1. Polyunsaturated fatty acids were higher at stations M2 and M4, while long-chain fatty 

acids, typically representative of higher plants, were highest at station M1. In the sterols, dinosterol was 

observed in significant amounts across the four samples but was highest at station M4. Brassicasterol, a 

diatom specific sterol (Volkmann 1986), was absent at M1 but seen at stations M2 through M4 (Figure 

39). Several sterols more specific to higher plants, including 24-ethylcholestan-3b-ol, decreased further 

offshore, while increases in marine diatom related markers such as brassicasterol, 24-methylcholest-7-22-

en-3β-ol and polyunsaturated fatty acids (PUFAs) occurred at mid-shelf and offshore stations. 
56

Figure 39. The distribution and abundance of major sterol markers plus phytol across the 

Mackenzie shelf transect. 

Fatty acid and sterol biomarkers show increases in marine related markers from M1 to the M4 stations. Diagnostic 

markers of higher plants, including long-chain fatty acids, 24-ethylcholestan-3β-ol, and isofucosterol, decrease further 

offshore. In contrast, increases are seen in broader measures of phytoplankton as phytol plus specific marine algal 

markers, including brassicasterol and 24-methylcholest-7-22-en-3β-ol, at mid-shelf and offshore stations.

4.3.5 Meiofaunal Community

Abundances of surface deposit feeders dominated the meiofaunal population across the four stations. 

Abundances were highest and most diverse at the mid-shelf stations (M2 and M3). Wet weight biomass 

calculated for the meiofaunal organisms was highest at station M4, while calculated dry weight biomass 
57

was greatest at M3 (Table 7). Foraminifera was the most abundant taxa, with increasing abundance 

toward greater depth. Harpacticoid copepods and diatoms were the second most abundant taxa with their 

maximum abundances occurring at the mid-shelf stations (Figure 40). The major taxonomic groups that 

were most abundant did not account for greatest calculated biomass; Sipunculida and Bivalvia 

outweighed copepods and diatoms, while small Foraminfera provided significant contribution to the 

biomass calculation (wet and dry weight). Abundances of non-protist, non-algal related organisms were 

low, however there were 23 Families of Polychaeta and 19 Families of Crustacea identified from the 

samples (Appendix B).
58

Table 7. Calculated wet and dry weight biomass (grams) based on literature values for major meiofaunal taxonomic groups identified 

from MARES cross-shelf transect.

Taxonomic Group

M1 

Abundance

M1 Wet 

Biomass

M1 Dry 

Biomass

M2 

Abundance

M2 Wet 

Biomass

M2 Dry 

Biomass

M3 

Abundance

M3 Wet 

Biomass

M3 Dry 

Biomass

M4 

Abundance

M4 Wet 

Biomass

M4 Dry 

Biomass

Polychaeta 47 0.1753 0.0088 67 0.2499 0.0126 144 0.5371 0.0271 122 0.4550 0.0230

Oligochaeta 1 0.0001 <0.0001 0 0.0000 0.0000 0 0.0000 0.0000 0 0.0000 0.0000

Acari 0 0.0000 0.0000 0 0.0000 0.0000 0 0.0000 0.0000 3 0.0012 0.0001

Ostracoda 0 0.0000 0.0000 0 0.0000 0.0000 10 0.0004 0.0002 3 0.0001 0.0001

Tanaidacea 6 0.0005 <0.0001 7 0.0006 <0.0001 4 0.0003 <0.0001 3 0.0003 <0.0001

Amphipoda 6 0.0020 <0.0001 2 0.0007 <0.0001 3 0.0010 <0.0001 0 0.0000 0.0000

Isopoda 3 0.0222 0.0011 0 0.0000 0.0000 5 0.0370 0.0018 2 0.0148 0.0007

Cumacea 0 0.0000 0.0000 0 0.0000 0.0000 5 0.0010 0.0001 2 0.0004 <0.0001

Copepoda 15 0.0001 <0.0001 165 0.0011 0.0003 254 0.0017 0.0004 101 0.0007 0.0002

Anthozoa 0 0.0000 0.0000 0 0.0000 0.0000 1 0.1172 1.6759 0 0.0000 0.0000

Foraminifera 251 0.2742 0.0041 493 0.5386 0.0080 651 0.7112 0.0106 946 1.0335 0.0154

Kinorhyncha 0 0.0000 0.0000 12 <0.0001 <0.0001 61 0.0001 0.0001 14 <0.0001 <0.0001

Bivalvia 0 0.0000 0.0000 4 0.2324 <0.0001 27 1.5686 0.0001 20 1.1619 0.0001

Nematoda 10 0.0002 <0.0001 50 0.0008 <0.0001 334 0.0056 0.0001 276 0.0046 0.0001

Nemertea 9 0.0036 0.0002 7 0.0028 0.0001 6 0.0024 0.0001 4 0.0016 0.0001

Priapulida 0 0.0000 0.0000 0 0.0000 0.0000 11 0.0634 0.0065 3 0.0173 0.0018

Sipunculidae 0 0.0000 0.0000 0 0.0000 0.0000 1 0.3038 0.0174 10 3.0383 0.1736

Diatoms 0 0.0000 0.0000 259 0.0000 0.0000 365 0.0000 0.0000 80 0.0000 0.0000

Ascidiacea 0 0.0000 0.0000 7 0.9124 0.1472 2 0.2607 0.0420 17 2.2158 0.3574

Plathyhelminthes 0 0.0000 0.0000 1 0.0254 0.0012 0 0.0000 0.0000 0 0.0000 0.0000

Total 348 0.478 0.0144 1,074 1.965 0.1696 1,884 3.612 1.7826 1,606 7.946 0.5726
59

Figure 40: Meiofaunal abundances and biomass that represent the majority of the benthic 

community in the meio size range. 

Overall trends across the shelf show larger communities at the mid-shelf stations with corresponding increase in 

diversity at these mid-shelf stations (M2 and M3). (A) shows the top seven benthic communities, which make up the 

majority of the biomass but very little of the overall abundances. (B) represents the seven most abundant benthic 

meiofauna which make up a smaller portion of the biomass than those benthic animals that are larger and contribute 

more to the total biomass.

4.4 Discussion

Past studies have used various suites of organic carbon signatures (i.e., long-chain n-alkanes, fatty acids 

and alcohols, triterpenoids) to quantify the input and movement of terrestrial carbon to the Arctic Ocean

(e.g., Belicka et al. 2004, Boucsein and Stein 2000, Goñi et al. 2005 Schubert and Calvert 2001, Stein et 
60

al. 1994, Taylor and Harvey 2011). Although these studies show that terrestrial carbon is both ubiquitous 

and varied in contribution, information on the response of the benthic community is limited. Although 

this limited set of stations provides only a snapshot of the organic sources and meiobenthic diversity 

across the Mackenzie shelf, it suggests that benthic abundance reflects marine inputs to sediments. 

Previous work along the Mackenzie shelf has shown that sinking fluxes are generally highest early in the 

summer (June, July, and August) and generally similar each year during the fall (Pedersen et al. 2010). 

On the eastern Beaufort Sea shelf, Mackenzie River melt water and an increase in solar and nutrient 

fluxes can lead to highest sinking fluxes of carbon in the summer (O’Brien et al. 2006). Although there 

are no previous carbon sediment measurements in the vicinity of our mooring locations, the low carbon 

values we measured in the sediments at stations M3 and M4 agree well with previous estimates of carbon 

flux measured on the Mackenzie shelf below the euphotic zone in fall (Pedersen et al. 2010). Station M2, 

a mid-shelf station, was the highest in organic carbon in the sediments and showed the greatest 

fluorescence maximum of the water column. This suggests these mid-shelf stations receive a substantial 

organic input from marine sources rather than river deposition. The lack of grain size differences across 

shelf stations (Figure 35) suggests that grain size has little impact on the community structure. Work by 

T. Richerol et al. (2008) concluded that the first 1 cm of sediments are heavily bioturbated at M3 and M4, 

suggesting that the material deposited across the Mackenzie Delta shelf includes a mixture of terrestrial 

deposition, labile marine production, and in situ benthic activity. 

The range of amino acids contributing to the total organic carbon (TOC) present in surface sediment was 

considered low for coastal shelf values. Station M1 has the lowest value in the sediments at only 1.1% 

THAA, with an increase of THAA in the sediments at station M2 and moving further offshore at stations 

M3 and M4. In the water column, the highest THAA contributions occur at the fluorescence maximum of 

station M4 (3.5%). This increase in THAA in the sediments and POC could suggest an offshore

production of material not related to terrestrial inputs. Total amino acids per unit carbon suggested that 

mid-shelf stations receive the highest deposition of labile organic matter to the sediments and the highest 

water column production furthest offshore at station M4. Past studies of amino acids in marine organic 

matter showed that relative abundances of GABA present in a sample (% GABA) can be used to 

represent the level of degradation of organic material (e.g., Keil et al. 1998). Across the MARES sites 

examined, the GABA fraction in surface sediments, as well as POM at the fluorescence maximum,

increased from inshore to offshore and consistently indicated the presence of degraded organic matter as 

an important component. Keil et al. (1998) determined that sediment samples low in organic carbon are 

often higher in non-protein amino acids like GABA, which are produced in situ rather than sourced from 

depositing POM. Increases in GABA in POM may also suggest more mixed sources of amino acids 

further offshore. The increased concentration seen in GABA offshore is balanced by the decrease seen in 

glutamic acid, which acts as the primary substrate to be decarboxylated to GABA. Other amino acids of 

interest included glycine, serine, and threonine, which are well preserved in diatom frustules. In the four 

cross-shelf stations, glycine, serine, and threonine contribute to a larger fraction to the sediment amino 

acids then those found in the water column POM. 

Overall results for fatty acid and sterol biomarkers as a fraction of organic carbon showed increases in 

algal related markers across the shelf, while long-chain fatty acids and sterols with higher plant origins 

decreased from M1 through M4. The presence of other marine related biomarkers, including the longchain fatty acids sourced from higher plant matter, were elevated closer to shore at stations M1 and M2 

(Figure 39). M1 is unique to the sampled transect with more than 50% of the measured organic matter 

apparently derived from terrestrial carbon. In contrast, station M2 and M3 appeared to have organic 

carbon largely derived from the water column, based on the presence of labile and diagnostic 

polyunsaturated fatty acids taxonomically specific sterol and diatom frustules present in samples (Figure 
61

41). These sources of organic carbon appear predominantly from water column production as opposed to 

particulate transport from the Mackenzie Delta and may include ice algal sources (Gradinger 2009).

Figure 41. Lipid and amino acid biomarkers of marine origin (panel A) verses summed organic 

markers both of terrestrial and marine organic matter (panel B). 

Marine biomarkers suggest an increase in marine materials at mid-shelf stations, while the terrestrial biomarkers are 

highest at station M1 (panel B). The sum of all amino acids (THAA) is also highest mid-shelf, suggesting an 

availability of labial material at these stations. Of the amino acids measured, glycine, serine, and threonine are 

enriched sediments due to their association with diatoms. Diatom levels as biomarkers match well with the increase 

in meiofaunal size class of diatom frustules in the sediments. The AIM site, a pelagic site comparable to that seen at 

station M4, is higher in liable amino acids representative of recent organic inputs.

Benthic meiofauna showed highest diversity and abundances at mid-shelf stations. Station M3 has the 

highest overall abundances and diversity in contrast to organic carbon in the sediments, which was 

greatest at station M2. Most of the benthic meiofauna identified were surface deposit feeders, who graze 

on available sources of organic matter near the sediment-water interface (Rhoades and Germano 1982).

The mismatch in organic carbon and benthic abundance and diversity can be explained by the fact that the 

multitude of surface deposit feeders at M3 are quickly taking advantage of available carbon and grazing it 

down more aggressively when compared to station M2. Station M1 had the lowest abundance, diversity, 

and organic carbon, which is thought to be a result of ice scouring and coarse sediment texture (mostly 

gravel and rocks). Station M4 had the second greatest abundance among the four stations sampled for 

meiofauna, with the greatest calculated wet weight biomass but lower dry weight biomass than station 

M3. This is related to the presence of larger benthic fauna identified further from shore. To support a 

community with larger organisms such as Sipuncula and Bivalvia, a larger source of fresh organic matter 

must reach the sediments from the water column or by other depositional processes. 

0

50

100

150

200

250

0

0.5

1

1.5

2

2.5

3

3.5

4

M1 M2 M3 M4

Abandances 

Concentration (mg/ g OC)

A

GLY+SER+THR

24-methylcholest-22-en-3b-ol

23,24-dimethylcholest-5-en-3b-ol

Brassicasterol

Diatom Frustles

* All other biomarkers data unavailable at this station

Note: Diatom frustules and meiofaunal data not available at the AIM site.

*

0

10

20

30

40

50

60

m1 m2 m3 m4 AIM

0-.5

Concentration (mg/ g OC)

B

GLY+SER+THR

THAA

sum of marine biomarkers

sum of terrestrial biomarkers

*
62

Results from the meiofauna population combined with information gathered from amino acids, carbon, 

and lipid biomarkers strongly suggested that the highest carbon fluxes and available (labile) organics in 

the sediments occur at mid-shelf stations, and that these are fueled by marine sources. Although we 

anticipated that inner-shelf stations would show highest carbon because of the large flux of POC 

associated with the Mackenzie River freshet, it may be that both summer zonal winds (see Section 2) and 

winter ice conditions interfered with this process, at least in 2016. In this area of the Beaufort Sea, the 

wintertime ice front extends from surface to the bottom in the nearshore, and if landfast ice persisted, it 

might have blocked the interaction of the Mackenzie River water (laden with particulates) with the coastal 

sea water early in the season (Carmack and Macdonald 2002; Macdonald et al. 2004). At the edge of this 

ice pack further away from shore but over the shelf, the annual sea-ice melt leads to ice edge blooms. 

Spring phytoplankton blooms in the Arctic, which may occur at a time when there are minimal to no 

additions of Mackenzie River POC, generally lead to large fluxes of marine carbon to the seafloor. 

Carbon fluxes in the water column subsequently increase as the condition become more favorable for 

phytoplankton production after the Mackenzie River runoff can flow over these mid-shelf areas. If such 

conditions coincided with zonal winds that favored easterly versus westerly transport of the plume during 

a significant amount of time in the spring and summer of 2016, it might explain why our observed results 

at the mid-shelf stations showed the highest amounts of carbon, diatom markers, diatom frustules, and 

benthic surface deposit communities, and why these originated predominantly from marine instead of 

from terrestrial sources.

4.5 Summary

The broad shelf off the Mackenzie Delta includes multiple sources of organic matter derived from both 

inflow and in situ production. Organic carbon, total THAA, and detrital grazers were highest at the midshelf stations (M2, M3) despite a uniform grain size across the four stations sampled across the Beaufort 

Sea shelf. Water column THAA are greater than that observed in the sediments analyzed, but the water 

column was lower in diatom related amino acids and higher non-protein amino acids than the sediment 

surface sampled. Lipid and fatty acid biomarkers also reflect that algal inputs to mid-shelf sediments are 

enhanced compared to terrestrial material, with major portions appearing as diatoms. The organic analysis 

completed as part of this MARES program agrees with benthic meiofaunal data measured with mid-shelf 

stations, which were highest in overall abundance. Although some taxa such as foraminifera increase 

further from shore, most of the measured parameters indicate that in situ marine production in the 

sediments and water column primary production are more important to carbon cycling and fluxes than 

previously reported. The data also suggest that inputs from Mackenzie River freshet may not be the 

dominant source responsible for supporting marine benthic communities with labile organic carbon food 

sources. Subsequent benthic samples will be needed to estimate a regional carbon budget, determine 

residence times under different environmental conditions, and bound the measurements reported here.

4.6 Future Research

While this study provided an initial snapshot of the Mackenzie delta system and its physical setting, the 

limited sampling for other parameters of the system did not allow temporal trends to be determined. 

Future work should take advantage of the well informed physical setting to follow the production and fate 

of carbon across the land-ocean boundary to allow development of regional carbon budgets and long-term 

estimates of carbon sequestration. 
63

5 Conclusions

The components of MARES aimed to:

1. Start the collection of physical, biological, and chemical observations in the Eastern Beaufort Sea 

from moored platforms

2. Describe and analyze physical, biological, and chemical observations acquired from a moving 

platform 

3. Gather water and sediment samples at the mooring locations simultaneously with the mooring 

deployment operation to estimate the carbon budgets and describe carbon cycling processes

The successful deployment of this unique array of moorings is providing us with a yearlong time series of 

the biophysical and chemical characteristics across the eastern Beaufort Sea shelf and continental slope, 

allowing us to capture regional ecosystem drivers in this region, including the influence of the Mackenzie 

River plume. 

The successful deployment of the Slocum G2 Glider and the subsequent high-resolution data collected 

provided insights into the flow of the Mackenzie plume, identifying four different plume flow regimes, as 

well as the temporal and spatial scales at which key processes are occurring. These flow regimes, largely 

influenced by wind forcing, have significant impacts on the final destination of the plume waters, their 

retention within Arctic waters, and their influence on biological communities, with implications for 

potential anthropogenic impacts such as those that may be predicted by regional oil trajectory models.

Sediment samples provided a snapshot of the organic sources and meiobenthic diversity across the 

Mackenzie shelf and suggested that benthic abundance reflects marine inputs to sediments (water column 

production) rather than river deposition. Benthic meiofauna patterns, however, may vary across years 

depending on zonal winds causing opposing directional transport of Mackenzie plume material. 
64

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Appendix A: 2015 Post-Cruise Report
Post-Cruise Report for Pilot 

Biophysical and Chemical 

Observations Program: Marine 

Arctic Ecosystem Study 

Contract M14PC00008 

Task Order 2 M15PD00012 

Prepared for: 

Department of the Interior 

Bureau of Ocean Energy 

Management 

US Department of Interior 

Bureau of Safety and 

Environmental Enforcement 

Procurement Branch, HQ 45600 

Woodland Road, Sterling, VA 

20166-9216 

Prepared by: 

Stantec Consulting Services Inc. 

4500 Daly Drive, Suite 100 

Chantilly, VA 20151-3724 

October 16, 2015 
POST-CRUISE REPORT FOR PILOT BIOPHYSICAL AND CHEMICAL OBSERVATIONS PROGRAM: MARINE 

ARCTIC ECOSYSTEM STUDY 

Francis Wiese, Ph. D. 

Program Technical Director 

Alexandra Eaves Ph. D. 

Assistant Technical Director 

Reviewed by: 

Diane Ingraham Ph. D., PMP 

Project Manager 

for:
POST-CRUISE REPORT FOR PILOT BIOPHYSICAL AND CHEMICAL OBSERVATIONS PROGRAM: MARINE 

ARCTIC ECOSYSTEM STUDY 

Table of Contents 

1.0 INTRODUCTION ................................................................................................................ 1

2.0 CRUISE DEPLOYMENT TIMING AND LOCATION ............................................................. 1

3.0 MOORING ARRAY SENSORS AND DEPLOYMENT ........................................................... 9

4.0 AUTONOMOUS GLIDER SENSORS AND DEPLOYMENT ................................................. 10

5.0 SCIENCE TEAM ............................................................................................................... 14

6.0 SUMMARY ....................................................................................................................... 15

7.0 BIBLIOGRAPHY ............................................................................................................... 15

 

LIST OF APPENDICES 

APPENDIX A MOORING DESIGNS
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ARCTIC ECOSYSTEM STUDY 

INTRODUCTION 

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1.0 INTRODUCTION 

The MARES 2015 Pilot Biophysical and Chemical Observations Program Task Order 3 

(M15PD00012) cruise planned for deployment of an autonomous glider for approximately six 

weeks, and deployment of a mooring array to be retrieved in the summer of 2016. Deployment 

was planned for the eastern U.S. Beaufort Sea with the objective of testing the latest technology 

and equipment to acquire biophysical and chemical time series data, and work towards 

describing the biogeochemical impact of the Mackenzie river plume in that area. For the 

mooring devices to be deployed during whaling season, BOEM and the Alaskan Eskimo Whaling 

Commission had agreed on August 21, 2015 to proceed only with mooring deployment once 

the communities of Nuiqsut and Kaktovik had completed their annual harvest of bowhead 

whales. 

2.0 CRUISE DEPLOYMENT TIMING AND LOCATION 

The planned cruise deployment timing and location was previously described in Stantec’s PreCruise Report for Pilot Biophysical and Chemical Observations Program: Marine Arctic Ecosystem 

Study (Stantec, 2015). The actual cruise deployment timing and location is described below. 

Pre-cruise mobilization 

• July 17, 2015, shipment of the mooring devices from Woods Hole Oceanographic Institution 

(WHOI) (Woods Hole, MA). 

• July 23, 2015, shipment of tall mooring devices from ASL Environmental Services (Victoria, 

BC). 

• August 3, 2015, WHOI mooring devices arrived in Cordova, AK. 

• August 5, 2015, shipment of the glider from Teledyne Webb Research (TWR) and arrival in 

Nome, AK on August 17, 2015. 

• August 14, 2015, Cruise deployment stand-down to revise schedule to avoid interference 

with Bowhead whale harvest for the Communities of Kaktovik and Nuiqsut, AK. 

• August 21st, 2015 ASL mooring devices arrived in Cordova, AK. 

• August 21, 2015, mooring cruise timeline was postponed for twelve days to September 7, 

2015 to accommodate commencement of the bowhead whale harvest for the communities 

of Kaktovik and Nuiqsut, AK. 

• August 24, 2015, the MARES mooring devices were loaded aboard the U.S. Coast Guard 

Cutter Sycamore (WLB-209) (225ft long), in Cordova, AK. The vessel departed for Nome on 

August 26, 2015. 

• September 1, 2015, Donglai Gong (VIMS) arrived in Nome AK for pre-deployment field testing 

of the glider which had been stored at UAF since its shipment to Alaska from the 

manufacturer TWR in Virginia. 
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• September 2, 2015, the glider was powered on, the vacuum pressure in the internal 

compartments held, and there were no obvious issues following shipment from the 

manufacturer. The glider was not opened again after assembling and testing at TWR. 

• September 3, 2015, both glider compass calibrations and a submersion test were performed 

from shore in Nome, AK (Figure 1). The glider was deemed fully prepared and tested, as of 

September 4, 2015, and ready for loading aboard the USCG Sycamore. 

• September 7, 2015, the first two members of the pilot cruise Science team, Principal 

Investigator, Robert Pickart, and Software Architect, Carolina Nobre, (both from Woods Hole 

Oceanographic Institute (WHOI)), boarded the USCG Sycamore. The glider and calibrated 

mooring ADCP sensors were loaded and stowed, the large mooring components were 

already aboard (Figure 2). 

Photo 1 Dr. Donglai Gong, from the Virginia Institute of Marine Science on shore in 

Nome Alaska with the autonomous glider during pre-deployment testing 

September 3, 2015.
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Photo 2 MARES mooring devices on deck aboard the USCG Sycamore in Nome 

AK, September 7, 2015. Shown here are the WHOI tripod and tall moorings 

intended for the 50 m and 120 m isobaths respectively. 

Cruise Timeline and Details 

• September 7, 2015, the USCG Sycamore departed from Nome, AK, to start the mooring 

cruise and headed towards Point Hope where the USCG conducted its outreach activities 

on Friday, September 11, 2015, AK. 

• Due to inclement weather conditions, the Community Observer, Ray Kious, was delayed in 

arriving from Nome in time for vessel departure. He therefore was re-directed to join the 

vessel in Barrow, AK. 

• September 8, 2015, glider team (VIMS) returned to Virginia. 

• Mooring technician, Jim Ryder, who was to depart WHOI to meet the ship in Barrow, had a 

death in his immediate family. Another experienced mooring technician from WHOI, Steve 

Murphy, was sent in his stead. 

• September 8, 2015, the Science crew aboard the USCG Sycamore was informed that Barrow 

intended to begin their hunt earlier than planned and that the USCG Sycamore could not 

enter port on September 15, for the scheduled rendezvous in Barrow. The rendezvous was 

rerouted to Kotzebue, AK. The remaining Science crew personnel and equipment were 

diverted to Kotzebue. The partnering program at UAF, providing a fifth mooring device for 

the MARES array, was also notified to redirect their mooring device to meet the vessel. 

• September 9, 2015, Kaktovik whaling season began. 
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• September 11, 2015, Environmental factors that could affect the deployment mission were 

favorable; the weather was improving at the deployment location, and the target location 

for the mooring array line was ice-free. The community of Nuiqsut, AK had already 

completed their harvest. Even though the community of Kaktovik, AK, approximately 60 miles 

to the east of Nuiqsut, AK, had started their hunt, they were weathered-out and did not 

achieve any of the three allotted strikes they needed to make up their annual subsistence 

harvest. Historically, the community of Kaktovik has completed their harvest by September 

12. 

• September 13, 2015, the USCG Sycamore’s bathymetric system was ground-truthed by 

repeating a part of a Kotzebue section that was done in NASA’s multi-year ship borne study 

of the Impacts of Climate on the Eco-Systems and Chemistry of the Arctic Pacific 

Environment (ICESCAPE) program. The comparison was excellent, within about 1 m of the 

calculated bottom from ICESCAPE. 

• September 14, 2015, a review of the latest International Bathymetric Chart of the Arctic 

Ocean (IBCAO) (version 3.0) in the MARES region revealed a bathymetric feature near the 

outer-shelf or shelf break where the planned MARES mooring line was to be positioned. This 

feature was not apparent in previous bathymetric survey resources including the National 

Oceanic and Atmospheric Administration’s 2-Minute Gridded Global Relief Data (ETOPO2) 

and the two previous versions of IBCAO. To avoid the array measuring anomalous 

hydrographic conditions due to local topography, it was moved approximately 40 km west 

of the original longitude in the eastern US Beaufort Sea (Figure 3). Final deployment location 

would still be subject to change when bathymetric survey is conducted on-site. 
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Figure 2-1 Revised study area and proposed deployment locations of MARES mooring array and a

glider flight path (right chart). The left chart (included for reference from (Stantec, 2015)

original pre-cruise planned study area with proposed deployment locations. Mooring drevised to be deployed on the shelf break along ~ 50, 140, 350 and 650 meter isobaths Red line indicates the USCG Sycamore tract, magenta line indicates intended USCG Sy

to glider deployment location, magenta square, location of glider deployment (1500m 

red stars indicate WHOI Moorings, small blue stars indicate ASL Moorings, large red star left indicates Cross Island, and large red star nearshore on right indicates Kaktovik. The UAF mooring (small black star nearshore) was not redirected to Kotzebue in time to be USCG Sycamore. Therefore the 12 m isobath mooring was not going to be part of this m

145oW

70oN 
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• September 15, 2015, the onloading of both mooring technicians, Steve Murphy (WHOI) and

Nikolai Milutinovic, (ASL Environmental Sciences), Community Observer, Ray Kious (UIC), and 

all remaining MARES mooring equipment was successful. 

• The partnering UAF mooring device did not arrive in Kotzebue in time and missed the 

deployment cruise.

• September 16, 2015, the BOEM Alaska COR notified Stantec of Kaktovik’s first whale strike; 

however, the animal was compromised and was not counted as one of the three 

subsistence strikes. Stantec relayed this information to the Science Crew aboard the USCG

Sycamore. 

• September 17, 2015, the USCG Sycamore arrived at the longitude of Barrow and held 

position until approval to proceed eastwards towards Kotzebue was received from USCG 

Command D-17, following communication between the Community Observer Ray Kious, 

and the AEWC. 

• September 19, 2015, the USCG Sycamore was holding 50 nautical miles offshore while 

awaiting the community of Kaktovik to complete their strikes. 

• September 20, 2015 Stantec formally requested assistance from BOEM to re-engage with 

AEWC to allow for coordination between the AEWC and the Community Observer aboard 

the vessel (Ray Kious) for mooring deployment activities to be conducted during marginal 

whaling conditions (such as high sea state or low light conditions). Otherwise the vessel 

would have to leave the area no later than noon on September 25, 2015, due to fuel and 

food constraints aboard the vessel. 

• September 21, 2015, the autonomous glider was deployed, and during its first dive at 200 

meters a leak was detected and the glider was immediately recovered by the USCG

Sycamore. The glider was stored on and not below deck as a precaution in case of 

interaction between the lithium battery and seawater potentially releasing hydrogen gas. 

• September 21, 2015, in response to Stantec’s formal request to BOEM, BOEM responded that 

the agreement between BOEM and AEWC would remain intact. Briefly, this August 21, 2015 

agreement between BOEM and AEWC, stated in an email to James Kendall (BOEM) from 

Jessica Lefevre on behalf of the AEWC Chairman, Mr. Harry Bower, reinforced: “... 

assurances provided by BOEM, that the vessel will traverse the Beaufort Sea well offshore (to 

the extent possible given ice cover) and will remain offshore until the close of fall whaling at 

Kaktovik and Nuiqsut...”. 

• September 22, 2015, Stantec informed the BOEM CORs that due to the combined factors of 

low probability of the whaling community of Kaktovik obtaining three strikes in time for the 

USCG Sycamore to then conduct bathymetric surveys and mooring deployment before 

needing to return to port (three strikes in one day with few whales in sight), and a 

deteriorating forecast in the western Beaufort that the vessel would be transiting through it 

was decided to prioritize the safety of the vessel the mooring deployment cruise was 

terminated and the USCG Sycamore headed for port in Nome, AK. 
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Post-Cruise Demobilization 

• September 28, 2015, D. Gong (VIMS), Principal Investigator for the autonomous glider portion 

arrived in Nome, AK to conduct a necessary safety inspection before shipment of the glider 

would be possible. 

• September 29, 2015, Mooring equipment and autonomous glider were offloaded from the 

USCG Sycamore. Principle Investigator D. Gong, powered on the glider in an outdoor field as 

a precaution to check if there was any seawater near the lithium battery, and to assess its 

performance compared to pre-leak detection readings. 

• September 30, 2015, D. Gong conducted a preliminary assessment of the condition of the 

glider’s internal components and found evidence of saltwater entry in the forward bay. The 

glider was then packaged for shipment back to TWR, the manufacturer, who had installed 

all components on the glider prior to the pilot mission. 

• October 2, 2015, glider packed up for shipment to TWR.

A summary of logistical changes to the deployment cruise are included in Table 2.1. 

Table 2.1 Summary of scheduling changes to the 2015 MARES pilot biophysical and 

chemical oceanography deployment cruise. 

Activity Original 

date 

Revised 

date 

Final Change 

Load mooring gear in Cordova:

Date postponed due to deployment cruise 

stand-down to allow for respectful discussion 

with MARES program partners and AEWC 

regarding concerns of proposed pilot 

mooring cruise activities in proximity to 

whaling season. 

Aug. 13, 

2015 

Aug. 

25, 

2015 

none 

Load remaining gear and vessel departure 

with part of science party and community 

liaison in Nome AK and depart the following 

day: 

The loading date cannot be delayed further 

due to unavailability of the pier in Nome, AK. 

Aug. 25-

26, 2015 

Sept. 6-

7, 2015 

none 

Due to adverse weather conditions, the 

Community Observer could not travel to 

Nome, AK in time for vessel departure and 

joined the vessel in Kotzebue, AK. 

Sept. 7th, 

2015 

Sept. 

15th, 

2015 

Community observer and remaining 

Science crew boarded in Kotzebue.

Mooring technician Jim Ryder had a death in 

the immediate family and was replaced by 

another WHOI mooring tech, Steve Murphy. 

NA NA Replacement Science crew 

member 

Review of latest bathymetric data resource 

(IBCAO v.3.0)identified an anomaly at target 

MARES mooring deployment region not 

present in previous data 

NA Sept. 

14th, 

2015 

Relocation of MARES target line 

approximately 40 km west of 

previous area to avoid distortion 

from bathymetric anomaly. 

Embark WHOI tech and remaining WHOI gear 

in Barrow: 

NA Sept. 

15, 

Community of Barrow, AK began 

whale harvest early and the vessel, 
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ARCTIC ECOSYSTEM STUDY 

CRUISE DEPLOYMENT TIMING AND LOCATION 

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Activity Original 

date 

Revised 

date 

Final Change 

Second crew load phase was required to 

accommodate air shipment logistics from 

WHOI (MA) that require more lead time, and 

remaining WHOI mooring technician is not 

available for Sept 7 2015 loading and 

departure date. Historically, Barrow does not 

start whaling until late-September, and Barrow 

Communications Center had confirmed the 

USCGC Sycamore could do small boat 

operations until Sept. 15th, 2015. 

2015 remaining Science crew and gear 

had to be diverted to Kozebue, AK 

for secondary onload.

Mooring from partnering UAF program did 

not arrive in Kotzebue in time 

Sept. 

15th, 

2015 

not 

available Partnering UAF mooring not loaded 

aboard USCG Sycamore for 

deployment 

Approximate arrival date at MARES study 

region in eastern U.S. Beaufort: Date initially 

postponed to minimize interference with 

whaling activities in Kaktovik and Nuiqsut, AK. 

Sept. 1, 

2015 

Sept. 

19th, 

2015

Longer transit from Kotzebue to 

study region, and vessel had to hold 

offshore for 1 day while awaiting 

approval from USCG to proceed 

East towards study region. 

Autonomous glider deployment from USCG 

Sycamore in MARES study region 

(approximate date): Date initially postponed 

to accommodate later deployment cruise 

timeframe. 

Sept. 1, 

2015 

Sept. 

21st, 

2015 

Longer transit from Kotzebue to 

study region, and vessel had to hold 

offshore for 1 day while awaiting 

approval from USCG to proceed 

East towards study region. 

Autonomous glider recovery Ending 

2nd

week of 

Oct. 

2015 

Sept. 

21st, 

2015

Early recovery of the autonomous 

glider was necessary as a leak was 

detected in the device at a depth 

of 200m and the condition of the 

internal components was unknown. 

Disembark science party in Barrow, AK: Date 

initially postponed to accommodate later 

deployment cruise timeframe (Sept. 22nd, 

2015). 

Sept. 8, 

2015 

Sept. 

26th, 

2015 

Science party disembarked in 

Kotzebue instead of Barrow (whaling 

season was underway), there was a 

longer transit time from study region 

to Kotzebue, AK. 

Unload mooring gear and glider from USCG 

Sycamore 

NA Sept. 

29th

2015

Moorings not deployed, require and 

shipment back to home institutions. 

Demobilization of autonomous glider and 

shipment back to manufacturer for 

diagnostics and integrity assessment. 

Second 

week of 

October 

Oct. 

2nd, 

2015

Potential for hydrogen to off-gas 

from interaction between lithium 

battery and seawater had to be 

assessed prior to shipment. 
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ARCTIC ECOSYSTEM STUDY 

MOORING ARRAY SENSORS AND DEPLOYMENT 

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3.0 MOORING ARRAY SENSORS AND DEPLOYMENT 

To address the objective of acquiring biophysical and chemical time series data a mooring 

array was to be deployed in the eastern U.S. Beaufort through the end of summer 2016 field 

season. The MARES mooring array consisted of 4 devices that were to be deployed along the 50 

m, 140 m, 350 m and 650 m isobaths to measure temperature, salinity, current velocity, 

fluorescence, abundance of fish and zooplankton, acoustics, photosynthetically active 

radiation, dissolved oxygen and turbidity. The approximate coordinates were revised to 

accommodate the detection of a bathymetric anomaly and would need to be finalized 

according to site-specific bathymetric data acquired on-site. All sensory components of each 

mooring were loaded aboard the USCG Sycamore and ready for deployment as described 

below, and drawings of each mooring are included in Appendix A. In partnership with UAF, 

ANIMIDA (PI Jeremy Kasper, the mooring array was to include a fifth device (second tripod) on 

the shelf at the 12m isobaths, however, it did not arrive at the revised secondary vessel loading 

site in Kotzebue, AK and was therefore not aboard the USCG Sycamore for the 2015 deployment 

cruise. A sixth mooring device to be positioned further east in the Mackenzie trough at around 

1000 m in partnership with Martin Fortier at ArcticNet was independent of the MARES 

deployment mission. The mooring components are now being shipped back to home institutions 

(WHOI and ASL). 

MARES mooring device specifications that were loaded aboard the USCG Sycamore (see 

Appendix A for drawings): 

1. Tripod, ~50m bottom depth, to be positioned at 70.1127 -141.8138 (revised to 70 23.8 

(N), 142 36.9 (W), 57m depth), with the following: 

• 300 KHz Acoustic Doppler Current Profiler (ADCP) for measuring ocean currents 

• MicroCAT for measuring conductivity, temperature and pressure 

• Inductive tether with 3 MicroCATs (28m, 22m, 16m) 

• Data logger 

• Dual releases 

2. Tall mooring, ~140m bottom depth, to be positioned at 70.3106 -141.6106 (revised to 70 31.7 

(N), 142 36.6 (W), 137m depth), with the following:

• Top float at 35m with the following: 

− Upward Looking Sonar (ULS) for providing under-ice topography data 

− 300 KHz ADCP for measuring ocean currents 

− MicroCAT for measuring conductivity, temperature and pressure 

− Data logger 

• Inductive tether with 3 MicroCATs (28m, 22m, 16m) 
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ARCTIC ECOSYSTEM STUDY 

AUTONOMOUS GLIDER SENSORS AND DEPLOYMENT 

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• McLane Moored Profiler (MMP), record water conditions daily with an acoustic, vector 

measuring current meter (ACM), dissolved oxygen, turbidity, fluorescence and 

(photosynthetically active radiation) PAR 

• MicroCAT below bottom stop for measuring conductivity, temperature and pressure 

• 300 KHz Acoustic Doppler Current Profiler (ADCP) below bottom stop for measuring ocean 

currents 

• Dual releases 

3. Tall mooring, ~350m bottom depth, to be positioned at 70.4062 -141.5137 (revised to 70 36.1 

(N), 142 36.5 (W), 386 m depth), with the following: 

• 1 x ASL Environmental Sciences Ice Profiler (IPS5) for measuring ice draft and surface waves 

• 4 x Sea-Bird Electronics MicroCAT C-T logger (SBE 37-M) for measuring conductivity, 

temperature and pressure 

• 2 x ASL Environmental Sciences Acoustic Zooplankton and Fish Profiler (AZFP) for bioacoustic 

backscatter 

• 1 x Teledyne RDI Acoustic Doppler Current Profiler (150kHz QM ADCP) for measuring ocean 

currents and ice velocity 

• 1 x Teledyne RDI Acoustic Doppler Current Profiler (75kHz ADCP) for measuring ocean 

currents 

• Dual releases 

4. Tall mooring, ~650m bottom depth, to be positioned at 70.5034 -141.4168 (revised to 70 40.1 

(N), 142 36.4 (W), 681m depth), with the following: 

• 1 x ASL Environmental Sciences Ice Profiler (IPS5) for measuring ice draft and surface waves 

• 4 x Sea-Bird Electronics MicroCAT C-T logger (SBE 37-M) for measuring conductivity, 

temperature and pressure 

• 1 x Teledyne RDI Acoustic Doppler Current Profiler (150kHz QM ADCP) for measuring ocean 

currents and ice velocity 

• 1 x Teledyne RDI Acoustic Doppler Current Profiler (75kHz ADCP) for measuring ocean 

currents 

• Dual releases 

4.0 AUTONOMOUS GLIDER SENSORS AND DEPLOYMENT 

To address the objective of testing the latest technology and equipment to acquire biophysical 

and chemical time series data, and to gain broader spatial biophysical and chemical data of 

the mooring array deployment region in the eastern U.S. Beaufort, an autonomous Slocum glider 

(~5 ft long), was deployed to measure physical, chemical and biological oceanographic 
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ARCTIC ECOSYSTEM STUDY 

AUTONOMOUS GLIDER SENSORS AND DEPLOYMENT 

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properties in a track surrounding the mooring array (Figure 2.1). Specifically, the glider was 

equipped as follows: 

• Seabird pumped CTD, collecting data on Conductivity-Temperature-Depth 

• WETLabs ECO Triplet puck (chlorophyll-a fluorescence, CDOM fluorescence, optical 

backscattering at 700 nm) 

• Aanderaa dissolved oxygen optode, measuring dissolved oxygen concentration 

• PAR sensor, to measure photosynthetically active radiation 

• Imagenex Model 853 scientific echo sounder (120 kHz), for measuring bioacoustic 

backscattering (acoustic plankton profiling). 

An extended buoyancy pump (800 cc vs 460 cc normal) and a hybrid thruster to provide an 

additional 1000 cc of active buoyancy for freshwater lens penetration. The glider was launched 

by the Science Team at the 1500m isobaths on the revised mooring deployment longitude. It will 

go westward initially from the eastern most offshore site, and monitoring and piloting of its initial 

performance will be conducted remotely (from shore), initially from Nome, AK, then from Virginia 

Institute of Marine Science. The glider will continually sample counterclockwise along the MARES 

TO3 glider sampling box with the following coordinates: 

Original glider transect coordinates: 

70.290 -143.120 (closest to Kaktovik) 

70.013 -141.830 

70.620 -141.200 

70.750 -142.630 

Revised glider deployment coordinates: 

The first waypoint was to the west of the mooring array, and following deployment it was to 

head for the third waypoint on the list and stay out of the whaling region until permission to enter 

was given. 

-142 50.00 70 34.00 Begin waypoint for eastern along-shelf segment 

 -144 27.00 70 46.00 End waypoint for eastern along-shelf segment 

 -144 37.00 70 57.00 Offshore waypoint of central cross-shelf section 

 -145 09.00 70 32.00 Mid-shelf waypoint of central cross-shelf section (42 m) 

 -145 12.00 70 52.50 Begin waypoint for the western along-shelf segment 

 -146 58.00 70 57.40 End waypoint for the western along-shelf segment 

 -147 15.00 71 04.00 Offshore waypoint of the western cross-shelf section 

 -148 12.50 70 40.00 Inner-shelf waypoint of the western cross-shelf section off Prudhoe 

Bay, (also glider recovery waypoint). 
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ARCTIC ECOSYSTEM STUDY 

AUTONOMOUS GLIDER SENSORS AND DEPLOYMENT 

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Alternate glider recovery point: 

 -147 50.00 70 35.00 

Depending on weather and sea conditions the estimated recovery for the glider was planned 

for the second week of October, at which time a separate charter vessel would have recovered 

the device. However, the glider had to be recovered by the crew of the USCG Sycamore early 

during its deployment mission as a leak was detected in the forward hull during the first dive at a 

depth of 200m. The glider crate was shipped from Prudhoe Bay (where it had been sent for the 

planned recovery), back to Nome, AK to be available for shipping the glider back to the 

manufacturer. 

Following offload from the USCG Sycamore there were signs of exterior damage to the glider 

incurred during recovery and storage on-deck for the steam back to Nome from off the coast of 

Kaktovik (E.g. broken wings and broken prop from being dragged backwards). However, all the 

sensors appeared to be intact with no obvious signs of damage. 

To assess the condition of the glider and safety for shipping, the manufacturer (TWR) advised 

that the glider be powered on outdoors to compare the output state of the glider since it was 

recovered. If only a small amount of water penetrated the glider it should have evaporated 

inside, and the leak detection voltage would have returned to normal. When the glider was 

powered on, the leak detect voltage had recovered significantly but was not back to normal, 

so some dampness was still suspected around near the leak indicator. Furthermore, the internal 

vacuum pressure held which indicated that the lithium battery was not interacting with 

seawater and outgassing hydrogen, and the battery appears to be functional as well. 

Following this initial assessment and in consultation with the manufacturer (TWR), the glider was 

opened and there was no sign of water presently in the glider except for a bit of dampness 

between the science bay and the forward section. Also there appeared to be no obvious signs 

of damage to any internal glider components, including the battery. However, it was evident 

that there had been a significant amount of water in the glider at one point. Salt deposits were 

found inside the nose section and along the bottom of the whole forward section to the science 

bay (Figure 4-1 A and B). Based on the salt signature, it was estimated there may have been at 

least 1/8 of the chamber with water lying on the bottom. The bulkhead at the science bay 

possibly prevented the water from entering the science bay and back section. The inside of the 

glider was left to dry out indoors to ensure any residual moisture evaporated. 

 
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ARCTIC ECOSYSTEM STUDY 

AUTONOMOUS GLIDER SENSORS AND DEPLOYMENT 

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A

B 

Photo 3 Internal hull of autonomous glider 417 showing dried saltwater residue (red 

arrows) in forward hull section, forward (A) and aft (B) bulkheads are 

shown. 

Further inspection of the O-rings revealed they were dirty with sand-like particles. The worst Oring was found between the forward section and the science bay. It’s not clear how the sand 

got into the glider's O-rings (Figure 4-2 A and B). 
POST-CRUISE REPORT FOR PILOT BIOPHYSICAL AND CHEMICAL OBSERVATIONS PROGRAM: MARINE 

ARCTIC ECOSYSTEM STUDY 

SCIENCE TEAM 

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A 

 B

Photo 4 Close-up of O-rings with indications of salt crystals (A) and sand-like 

particles (B). 

5.0 SCIENCE TEAM 

The Science Team members, their affiliations and their role for this MARES Pilot Biophysical and 

Chemical observations cruise were as listed below, changes to the original cruise plan are 

shown in red: 

• Dr. Robert Pickart, Woods Hole Oceanographic Institution, Chief Scientist 

• Steve Murphy, replacement WHOI mooring technician for Jim Ryder (WHOI) who had a 

death in his immediate family 

• Nikolai Milutinovic, ASL Environmental Sciences, Mooring Technician 

• Dr. Carolina Nobre, Woods Hole Oceanographic Institution, Software Technician 
POST-CRUISE REPORT FOR PILOT BIOPHYSICAL AND CHEMICAL OBSERVATIONS PROGRAM: MARINE 

ARCTIC ECOSYSTEM STUDY 

SUMMARY 

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• Ray Kios, UIC, Community Observer included as part of August 21, 2015 agreement between 

BOEM and AEWC. 

− Ray Kious was originally going to board the USCG Sycamore in Nome, AK along with the 

Chief Scientist. However, due to fog conditions he could not get to Nome in time for 

vessel departure. He was re-directed to join the vessel from Barrow then Kotzebue, AK 

when the Community of Barrow began its whale harvest early. 

The autonomous glider was deployed by the cruise Science Team members and monitored from 

shore: 

• Dr. Donglai Gong, Virginia Institute of Marine Science, Principal Investigator 

• Haixing (Daniel) Wang, Virginia Institute of Marine Science, Graduate Research Assistant 

6.0 SUMMARY 

All mooring and autonomous glider equipment and sensors were acquired, assembled and 

loaded aboard the USCG Sycamore as proposed for the MARES 2015 Pilot Biophysical and 

Chemical Observations Program. Several logistical changes were made prior and during the 

progress of the cruise (summarized in Table 2.1), and the USCG Sycamore arrived at the target 

mooring deployment longitude, and the autonomous glider was deployed. In respect of the 

August 21, 2015 agreement between BOEM and the AEWC, the USCG Sycamore did not 

approach the mooring deployment target locations as the community of Kaktovik, AK had not 

obtained its subsistence quota of bowhead whales (historically met by September 12, 2015), and 

in advance of a worsening sea state in the eastern Beaufort, the USCG Sycamore returned to 

port to prioritize the safety of the vessel and crew without having deployed the mooring devices. 

The autonomous glider detected a leak in its forward hull and had to be recovered by the USCG 

Sycamore early during its deployment mission on September 21, 2015. None of the equipment 

was lost, and there were no health and safety incidents reported during the entire premobilization process, during the cruise, and post-cruise mobilization process. A comprehensive 

Technical Report will be generated with detailed findings from the glider inspection and lessons 

learned to improve the success of the MARES program going forward. 

7.0 BIBLIOGRAPHY 

Stantec. (2015). Pre-Cruise Report for Pilot Biophysical and Chemical Observations Program: 

Marine Arctic Ecosystem Study. St. John's NL / Chantilly, VA: Stantec Consulting Services 

Inc.; August 5, 2015 
POST-CRUISE REPORT FOR PILOT BIOPHYSICAL AND CHEMICAL OBSERVATIONS PROGRAM: MARINE 

ARCTIC ECOSYSTEM STUDY 

APPENDIX A 

Mooring Designs 
POST-CRUISE REPORT FOR PILOT BIOPHYSICAL AND CHEMICAL OBSERVATIONS PROGRAM: MARINE 

ARCTIC ECOSYSTEM STUDY 

 A-1

WHOI bottom tripod mooring (depth ~50m) 
POST-CRUISE REPORT FOR PILOT BIOPHYSICAL AND CHEMICAL OBSERVATIONS PROGRAM: MARINE 

ARCTIC ECOSYSTEM STUDY 

 A-2

WHOI tall mooring (depth ~140m), the top float will be 35m below the surface 
POST-CRUISE REPORT FOR PILOT BIOPHYSICAL AND CHEMICAL OBSERVATIONS PROGRAM: MARINE 

ARCTIC ECOSYSTEM STUDY 

 A-3

ASL tall mooring (depth ~350m), the top float of the mooring 

will be approximately 70m below the surface. 
POST-CRUISE REPORT FOR PILOT BIOPHYSICAL AND CHEMICAL OBSERVATIONS PROGRAM: MARINE 

ARCTIC ECOSYSTEM STUDY 

 A-4

ASL tall mooring (depth ~650m), the top float of the mooring 

 will be approximately 70m below the surface. 
95

Appendix B: Feeding Guilds and Abundance

97

Table B-1. MARES sample feeding guilds and abundance.

Feeding Guild Phylum

Class/Subcl

ass Order Family Genus/Species

M1 M2 M3 M4

0-11-22-33-44-50-11-22-33-44-50-11-22-33-44-50-11-22-33-44-5

Annelida Polychaeta00000000004000050000

Surface Deposit Acrocirridae nr. Flabelligena cirrata00000000003000000000

Surface Deposit Ampharetidae000000000000010 204000

Head Down 

Deposit

Capitellidae00000120000292410041

Mediomastus sp.00000000110000000000

Barantolla sp.00000000010000000000

Surface Deposit Cirratulidae000003 12000 12600081000

Surface Deposit Cossuridae00000010000010000000

Surface Deposit Hesionidae00000100000000010000

Predatory Lumbrineridae00000000001000010100

Head Down 

Deposit

Maldanidae00000000000000004200

Predatory Nephtyidae10021 180000 17200010000

Predatory Nereidae010000000000000 240000

Scavengers Onuphidae00000100008000070000

Filter and 

surface deposit

Oweniidae00000100000000000000

Head Down 

Deposit

Paraonidae01000312009 1412203010

Head Down 

Deposit

Pectinariidae00000300000000010000

Predatory Pholoidae00001000000000000000

Predatory Phyllodicidae0000000000 10000030000

Filter Sabellidae00000020008010020000

Head Down 

Deposit

Scalibregmidae00000000001000000000

Predatory Sigalionidae20100000000000020000

Surface Deposit Sphaerodoridae00000000005100000000

Surface Deposit Spionidae44014200002301080000

Polydora sp.03200000000000000000

Predatory Syllidae 1531009000022300 142000

Surface Deposit Terebellidae00000100001000000000

Surface Deposit Trichobranchidae00000100004000010000

Oligochaeta10000000000000000000

Arthropoda00000000001000010000

Predatory Acari00000000000000030000

Surface Deposit Ostracoda00000000008110030000

Surface Deposit 

and Filter

Malacostraca Tanaidacea Akanthophoreidae00000000000000020000

Stenotanais sp.00000000000000010000

Akanthophoreus nr. 

gracilis

10000000004000000000

Surface Deposit

and Filter

Anarthruridae00000100000000000000

Surface Deposit 

and Filter

Paratanoidea incerta 

sedis

Leptognathioides nr. 

polita

05000000000000000000

Surface Deposit 

and Filter

Pseudotanaidae Pseudotanais sp.00000100000000000000

Surface Deposit 

and Filter

Typhlotanaidae Peraeospinosus sp.00000500000000000000

Surface Deposit 

and Filter

Amphipoda Aoridae Lembos sp.?00001000000000000000

Corophiidae Leptocheirus sp.02000000000000000000
98

Feeding Guild Phylum

Class/Subcl

ass Order Family Genus/Species

M1 M2 M3 M4

0-1 1-2 2-3 3-4 4-5 0-1 1-2 2-3 3-4 4-5 0-1 1-2 2-3 3-4 4-5 0-1 1-2 2-3 3-4 4-5

Isaeidae 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Lysianassidae 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Oedicerotidae 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0

Phoxocephalidae 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0

Stenothoidae 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Surface Deposit 

and Filter

Isopoda Desmosomatidae Eugerda sp. 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

Chelator sp. 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 1 0 0 0 0

Surface Deposit 

and Filter

Gnathiidae 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0

Gnathia nr. triloba 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Gnathia sp. 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Surface Deposit 

and Filter

Munnidae Munna stephenseni 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Surface Deposit 

and Filter

Paranthuridae 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

Surface Deposit 

and Filter

Cumacea Diastylidae Ektonodiastylis nr. 

nimia

0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 1 1 0 0 0

Surface Deposit Copepoda Harpacticoida 6 5 1 3 0 164 1 0 0 0 247 2 3 2 0 95 5 1 0 0

Filter Chordata Ascidiacea 0 0 0 0 0 7 0 0 0 0 2 0 0 0 0 17 0 0 0 0

Filter Cnidaria Anthozoa Hexacorallia Actiniaria 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

Photosynthetic Ochrophyta BacillariophyceaeDiatoms 0 0 0 0 0 210 49 0 0 0 115 250 0 0 0 80 0 0 0 0

Predatory Foraminifera 45 44 41 52 69 157 105 24 111 96 249 190 123 71 18 422 115 149 62 198

Predatory Kinorhyncha 0 0 0 0 0 12 0 0 0 0 60 1 0 0 0 14 0 0 0 0

Filter Mollusca Bivalvia 0 0 0 0 0 1 0 0 0 0 13 2 0 0 0 4 0 0 0 0

Mytilidae 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

Pectinidae 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

Thyasiridae 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

Mendicula ferruginosa 0 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 0 0 0 0

Thyasira nr. cygnus? 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 8 1 0 0

Yoldiidae Yoldiella spp. 0 0 0 0 0 3 0 0 0 0 1 0 0 0 0 4 0 0 0 0

Portlandia intermedia 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0

Predatory Solenogastres 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0

Surface Deposit 

and Predatory

Nematoda 0 5 0 5 0 47 0 2 1 0 163 140 10 18 3 107 126 27 12 4

Predatory Nemertea 7 2 0 0 0 7 0 0 0 0 3 1 0 0 0 2 2 0 0 0

Heteronemertea0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0

Surface Deposit, 

non-parasitic

Plathyhelminthes0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Predatory Priapulida 0 0 0 0 0 0 0 0 0 0 11 0 0 0 0 3 0 0 0 0

Surface Deposit Sipunculidae 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 9 1 0 0 0

Total Abundance 348 1074 1885 1607
Department of the Interior (DOI)

The Department of the Interior protects and manages the Nation's natural 

resources and cultural heritage; provides scientific and other information about 

those resources; and honors the Nation’s trust responsibilities or special 

commitments to American Indians, Alaska Natives, and affiliated island 

communities.

Bureau of Ocean Energy Management (BOEM)

The mission of the Bureau of Ocean Energy Management is to manage 

development of U.S. Outer Continental Shelf energy and mineral resources in 

an environmentally and economically responsible way.

BOEM Environmental Studies Program

The mission of the Environmental Studies Program is to provide the 

information needed to predict, assess, and manage impacts from offshore 

energy and marine mineral exploration, development, and production activities 

on human, marine, and coastal environments. The proposal, selection, research, 

review, collaboration, production, and dissemination of each of BOEM’s 

Environmental Studies follows the DOI Code of Scientific and Scholarly 

Conduct, in support of a culture of scientific and professional integrity, as set 

out in the DOI Departmental Manual (305 DM 3).