STUDY TITLE: Marine Arctic Ecosystem Study (MARES)

REPORT TITLE: Marine Arctic Ecosystem Study (MARES): Moorings on the Beaufort Sea Shelf 

2016-2018 and Program Synthesis

OCS STUDY NUMBER: BOEM 2020-029

NUMBER OF PAGES: 286

CONTRACT NUMBER(S): M14PC00008 M17PD00006

SPONSORING OCS REGION: Alaska

APPLICABLE PLANNING AREA(S): Beaufort Sea

FISCAL YEAR(S) OF PROJECT FUNDING: 2016; 2019

COST(S) BY FISCAL YEAR: 2016: $1,039,687.00; 2019: $92,163.12

CUMMULATIVE PROJECT COST: $1,131,850.12

COMPLETION DATE OF REPORT: September 11, 2020

PROJECT MANAGER(S): Diane Ingraham, Cathy Finnie

AFFILIATION OF PROJECT MANAGER: Stantec Consulting Services Inc.

ADDRESS: 4500 Daley Dr., Suite 100, Chantilly, VA 20151-3724 USA

PRINCIPAL INVESTIGATOR(S)*: Wiese FK, Ashjian C, Borg K, Fabijan M, Fissel D, Gryba RD, 

Lin P, Monacci N, Nelson RJ, Pickart R, Stafford K, Turner C.

KEY WORDS: MARES, Beaufort Sea, Mackenzie River, oceanographic moorings, currents, sea ice, 

water masses, nutrients, zooplankton, fish, ecosystem understanding

BRIEF ABSTRACT: The MARES project deployed 4 moorings in the Eastern Beaufort Sea in October 

2017, three of which stayed in the water for one year, and one mooring remained until summer of 2019. 

Five moorings had previously been deployed in fall 2016-2017. The moorings collected data from 

physical oceanography through to marine mammal vocalizations to better understand drivers and the 

influence of the Mackenzie outflow on the marine ecosystem in the Study Area. Measurements revealed

very large wind driven currents on the shelf and complex patterns of currents at greater depths. The direct 

measurements of sea ice from the MARES moorings revealed a very dynamic regime of sea ice motion. 

Zooplankton and Arctic cod biomass coincided with the productive period on the Beaufort Shelf, when 

sea ice is retreating, ice algal and water column primary production is initiated, and secondary production 

is ongoing. Detections of marine mammals largely reflected migratory patterns for bowhead and beluga 

whales, and breeding for bearded seals. Overall the project contributes continuous records of physical, 

chemical and biological parameters in the Eastern Beaufort Sea, providing invaluable data to better 

understand the ecosystem and its drivers and to build further programs. 

BACKGROUND: The Department of the Interior, Bureau of Ocean Energy Management (BOEM) and 

its partners 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, AK to the Mackenzie Delta coastline to a depth of 1,000 m.
* The affiliation of the Principal Investigator(s) may be different than that listed for Project Manager(s).

OBJECTIVES: The objectives of this Task Order were to retrieve moorings redeployed in the eastern 

Beaufort Sea in October 2017 and conduct preliminary analysis and interpretation of the data collected.

Additionally, we describe seasonal and interannual patterns and variability for different sensors deployed 

over the length of the program (2016-2019) and explore drivers behind observed patterns and variability. 

METHODS: The MARES 2017–2018 biophysical mooring array was a collaborative effort between 

Stantec, ASL, WHOI, UAF, SeaStar Biotech, and UW, with vessel support from DFO. Four moorings 

were deployed in the Eastern Beaufort Sea in the region of the Mackenzie Trough (Figure 1) in October 

2017, three (M2, M3, M4) were retrieved in October 2018, while M1 remained until October 2019 due to 

ice conditions. Sensors on the moorings included ADCPs, CTs, SUNAs, AURALs, AZFPs, and IPSs. 

CTD casts and water samples were also collected during deployment and retrieval of the moorings. Data 

were quality checked (QA/QC) and preliminary analysis conducted.

RESULTS: From 2017-2019 moorings and related activities, 31,717 raw data files were recovered from 

39 distinct instruments on the 4 MARES moorings, CTD casts, and water samples. Except for the SAMI 

deployed on M1, all equipment operated throughout the deployment period. High-speed current events 

were observed even in winter when ice was present. Largest events were in November, early in the sea ice 

season when sea ice is rapidly forming in the region. Along-stream current velocity combined with 

temperature and salinity profiles identified the presence of the shelf current, remnant winter water, and 

Atlantic water present at depth. Mean ice speed was largest at M1 (46.3 cm/s), followed by M2 (24.7 

cm/s); ice flow direction was generally from east to west following the general circulation pattern in the 

region. Nitrate concentrations reached a minimum over the summer months when nitrate consumption of 

organisms such as sea ice algae and phytoplankton are most active. Concentrations were renewed starting 

in the fall. Substantial seasonal variation in zooplankton was observed. Backscatter at M1 and M2was 

greatest near the surface. At M1, diurnal vertical migration occurred primarily during the summer (June–

August) months but was absent at M2. Juvenile Arctic cod were present near the surface (top 40m) from 

end of May through October, apparently moving deeper in the fall. The bulk of adult Arctic cod 

abundance was detected between September and April below 200 m depth. Bowhead whales, beluga 

whales, and bearded seal were detected in 2017-2018. Ringed seals were not heard. Bowhead and beluga 

whales were detected in the summer and fall; bearded seals were detected in late winter through summer.

CONCLUSIONS: Measurements from this multi-year, high-resolution, multi-disciplinary, cross-shelf

mooring array have provided new insights into the physical, chemical and biological characteristics in this 

study area, including new findings on circulation regimes, and the influence of key physical drivers and 

ecosystem properties. Further comparisons with physical and biological drivers will help identify 

mechanisms influencing the patterns observed during this program, adding to our understanding of the 

effects of the Mackenzie outflow on the Beaufort Sea. Additional research to continue physical, chemical 

and biological concurrent measurements, and integrating such studies with regional modeling efforts

would increase our capacity to understand the Beaufort Sea ecosystem and future trends and effects. 

STUDY PRODUCTS(S) to date: (1) BOEM study report: Wiese FK, Ashjian C, Asplin M, Borg K, 

Fabijan M, Fissel D, Gryba RD, Gong D, Harvey R, Lin P, McMahon R, Monacci N, Nelson RJ, Neubert 

P, Pickart R, Rousseau S, Stafford K, Turner C. 2020. Marine Arctic Ecosystem Study (MARES): 

Moorings on the Beaufort Sea shelf 2016-2018, and Program Synthesis. Anchorage (AK): US 

Department of the Interior, Bureau of Ocean Energy Management. OCS Study BOEM 2020-029. p. 308; 

(2) Lin P, Pickart RS, Fissel D, Ross E, Kasper J, Bahr F, Torres DJ, O'Brien J, Borg K, Melling H, 

Wiese F. 2020. Circulation in the vicinity of Mackenzie Canyon from a year-long mooring array. Prog 

Oceanogr.; (3) McMahon R, Taveras A, Neubert P, Harvey HR. 2020. Organic Biomarkers and 

Meiofauna Diversity Reflect Differential Carbon Inputs Across the Coastal Shelf of the Mackenzie Delta. 

Limnol. and Oceanogr. (in press) (4) Data are available on the AOOS portal and NCEI; (5) Conference 

presentations at AMSS (2019, 2020), ArcticNet (2019), and Ocean Sciences (2020).
Map of study area:

Figure 1. Location of the MARES 2017–2018 mooring array