# Presentation: 102294

## Ecosystem Changes/Processes in High LatitudesA. David McGuireU.S. Geological Survey/Institute of Arctic BiologyUniversity of Alaska Fairbanks  

**NASA CC&E Meeting**
**29 April 2008**

## Contributors

** ****K. Arrigo – Stanford University**
** ****J. Comiso – Goddard Space Flight Center**
** ****S. Doney – Woods Hole Oceanographic Institute**
** ****S. Goetz – Woods Hole Research Center**
** ****E. Kasischke – University of Maryland**
** ****J. Kimball – University of Montana**
** ****P. Matrai – Bigelow Laboratory for Ocean Sciences**
** ****K. McDonald – Jet Propulsion Laboratory**
** ****D. Walker – University of Alaska Fairbanks**
** ****T. Zhang – University of Colorado**

## Ecosystem Services: The benefits people obtain from ecosystems 

**Ecosystem Services:** The benefits people obtain from ecosystems

- Millennium Ecosystem Assessment 2005

## Ecosystem Services: Issues in Polar Regions

**(based on Chapin et al. 2005. Millenium Assessment. Polar Regions Chapter)**

***Climate Regulation***** **
**- carbon exchange with the atmosphere**
** ****methane exchange with the atmosphere**
** ****water/energy exchange**
** ****snow-vegetation interactions**
** ****vegetation changes**
** ****sulfate biogeochemistry and aerosols**
***Biodiversity, Health, and Provisioning***
** ****caribou and reindeer**
** ****marine fisheries**
** ****threatened/endangered species**
** ****invasive species**
** ****contaminants: oil, heavy metals, POPs**
** ****stratospheric ozone and UV-B**

## Organization of Talk

** ****Ecosystem Changes/Processes in **
**	****Northern Terrestrial Regions **
** ****Ecosystem Changes/Processes in **
**	****the Northern Oceans**
** ****Ecosystem Changes/Processes in**
**	****the Southern Ocean**
** ****Summary**

## Ecosystem Change and Processes in Northern Terrestrial Regions 

**Ecosystem Change and Processes in Northern Terrestrial Regions **

## Major Arctic Feedbacks to the Climate System

**Major Arctic Feedbacks to the Climate System**

- From Arctic Climate Impact Assessment. 2005.

## 30-45% of Global Soil Carbon in the Top 1 – 2 m of Soil 

**30-45% of Global Soil Carbon in the Top 1 – 2 m of Soil **
**is Stored in High Latitude Terrestrial Ecosystems**

***(Figure from Bajtes 1996)***

**Notes:**
In addition to these changes in vegetation structure, there changes in ecosystem function, particularly the storage and release of carbon from ecosystem through increases in soil decomposition. This is important because... 

## From Euskirchen et al. 2007

**1900     1910       1920       1930      1940      1950       1960       1970      1980       1990        2000**

**1940**

**1910**

**1970 - 2000**

**1970**

**2000**

**Air temperature anomaly **
**(oC, five year running mean)**

**Year**

**Air temperature anomaly (oC)**

**Five-Degree Latitudinal band (oN)**

**0.0078 – 0.0354 oC year****-1**

**0.0381 – 0.0388 oC year****-1**

**1910 - 1940**

## Between 1970 -2000, 

**Between 1970 -2000, **
**the number of days of snow covered ground **
***decreased by an estimated 2.5 days per decade****** ***
**across the pan-Arctic. **

**1970 -2000**

***From Euskirchen et al. 2007***

## Changes in atmospheric heating due to 

**Across the pan-Arctic, an overall reduction in the duration of snow covered ground by ~2.5 days per decade resulted in atmospheric heating of ~1.0 W m****-2**** per decade.**

**Changes in atmospheric heating due to **
**changes in the snow season, 1970-2000**

**1970 -2000**

***From Euskirchen et al. 2007***

**Notes:**
Notable heating increase in Alaska.

## Spring Thaw Timing Influences Northern Productivity

- _Source_: Kimball, McDonald, and Zhao, 2006. ***Earth Interactions.*** 10, 21 .

-  *Annual variability in AK springtime thaw from SSM/I record is ~ ±7 days (SD), with corresponding impacts to annual NPP of ±1% per day.*
* **Satellite (SSM/I) record shows earlier springtime thawing of -4.6 days per decade, sufficient to explain Northern greening and magnitude of satellite (AVHRR) productivity growth trends****.***

**Spring Thaw Timing Influences Northern Productivity**

- r = -0.688, P=0.009

- r = -0.857, P<0.001

## Trends In Photosynthetic Activity 1982-2005+Trend (-Feedback)  -Trend (+Feedback)

**Trends In Photosynthetic Activity 1982-2005**+Trend (-Feedback)  -Trend (+Feedback)

*Goetz et al. 2007 ERL*

**Notes:**
The values / colors in the image are slopes of significant trends in photosynthetic activity, i.e. they are changes over the 24 year period.  Where photosynthesis is going up it's bright green and where down it's bright red.  The background in that graphic is a MODIS satellite image (over land) and bathymetry over water. 

## Process studies across high-latitude ecosystems

**Process studies across high-latitude ecosystems**
**have provided synthetic analyses of how vegetation responds **
**to climate change, including their **
**water, energy, and CO****2**** exchange with the atmosphere.**

***Beringer et al., 2005***

## Summer net C exchange measured by a mobile eddy covariance tower compared with a reference stationary tower located in tundra

**Summer net C exchange measured by a mobile eddy covariance tower compared with a reference stationary tower located in tundra**

**Results indicate that transitions to shrub tundra and forest are likely to lead to greater summer C storage.**

**Carbon fluxes at Council, Alaska**** *****courtesy of C. Thompson***

## Summer Albedo

**Studies at Council, Alaska indicate that changes in vegetation distribution of Arctic Ecosystems will have substantial effects on summer water and energy exchanges between the land surface and the atmosphere (Thompson et al. 2005)**

**Summer Albedo**

**Strong relationships (R****2**** = 0.68 – 0.87; p < 0.0001) also exist between aboveground biomass and latent heat, sensible heat, and net radiation.**

**Aboveground biomass (g m****-2****)**

**Tundra**

**Low shrub**

**Tall shrub**

**Woodland**

**Forest**

## Combining remote sensing and traditional knowledge

***“...******in addition to taking part in daily life and seeing with our own eyes exactly how the animals are managed we ... do more formal semi-structured interviews. Some of these are recorded on either digital tape or film, or both. In these cases we have medium or very high resolution satellite imagery of the areas we are discussing to focus on specific places and features that the herders can recognize easily.”***
- --Bruce Forbes

- Walker et al., 2008,  Yamal NASA LCLUC project

## Trends In Photosynthetic Activity 1982-2005+Trend (-Feedback)  -Trend (+Feedback)

**Trends In Photosynthetic Activity 1982-2005**+Trend (-Feedback)  -Trend (+Feedback)

*Goetz et al. 2007 ERL*

**Notes:**
The values / colors in the image are slopes of significant trends in photosynthetic activity, i.e. they are changes over the 24 year period.  Where photosynthesis is going up it's bright green and where down it's bright red.  The background in that graphic is a MODIS satellite image (over land) and bathymetry over water. 

## Fire in the North American Boreal Region 

**Ignitions are for fires > 2 km****2  ****in size**

**Fire in the North American Boreal Region **

- E. Kasischke

**Notes:**
Here we show patterns of burned area across the NA boreal forest. 
While the area burned for the 1960s and 1970s are probably greater than reported in the records, even if we increase the fire activity by 30%, it is clear that there has been an increase in the frequency of fires in the 80s and 90s

The data also show that the influence of human ignited fires has decreased over this time period

Number of human ignited fires > 200 ha decreased betweens the 1960s to 1990s from 91/yr to 47/yr 

Number of lightning-ignited fires > 200 ha increased betweens the 1960s to 1990s from 137/yr to 270/yr 

While burned area has been increasing overall, influence of human-ignitions has decreased

## Frequency of large fire years in Alaska

*Frequency of large fire years in Alaska*

**1 every 6 years**

**1 every 3 years**

**Key:  ****less than 1% of land area burned, ****1-2% of land area burned,**
**2-3% of land area burned,**** ****> 3% of land area burned**

- E. Kasischke

**Notes:**
Here, we present a plot of annual burned area for AK through 2006, which is 7 years beyond the Kas and Tur. Study
Here we have a plot of annual burned area for Alaska going back to 1950
The colors of the bars denote the relative size of the fire year, where small fire years had < 1% of the interior region of AK burned, and ultra-large fire years had > 3%, with large being 1-2% and very large 2-3%

This plot shows that over the past 21 years

The frequency of large fire years has doubled, which has resulted
 In a 67% increase in average burned area

Since the mid-1980s, we have seen a doubling in the frequency of large fire years, that has led to a 67% increase in average burned area

## Upland black spruce fire chronosequence 

- Upland black spruce fire chronosequence
- in Delta Junction, Alaska (64oN)

*Photos: J. Randerson*

## Changes in surface albedo at the Delta Chronosequence

***Liu et al., 2005***

**Changes in surface albedo at the Delta Chronosequence**

- Grey line = Recent burn
- Black line = Control

## Drying of northern wetlands

**Drying of northern wetlands**

*Riordan et al. JGR. 2006*

**Notes:**
Recent remote sensing work led by Brian Riordan at the University of Alaska Fairbanks shows that open water bodies, such as these examples from the Yukon Flats, have lost considerable surface area since the 1950s.  Brian quantified similar trends in drying across several focal areas in Alaska.  We are very interested in understanding what these patterns of pervasive drying mean for wetland structure and function.   

Estimated changes in open water area for 9 focal area in Alaska between ~1950 and ~Present
Area	Percent change over 50 years	
Innoko Flats	-33	
Copper River Basin	-28	
Minto Flats	-21	
Yukon Flats	-18	
Talkeetna	-19	
Alma lakes	-15	
Stevens Village	-3	
Forty Mile Flats	3	
North Slope	1	

## Net Water Surface Area Loss in Alaska

| Study Region | Net percent change over 50 years |
| --- | --- |
| Innoko Flats National Wildlife Refuge  | -31 |
| Copper River Basin | -28 |
| Minto Flats State Game Refuge | -25 |
| Yukon Flats National Wildlife Refuge | -18 |
| Stevens Village  | -14 |
| Talkeetna | -5 |
| Denali National Park | -4 |
| Tetlin National Wildlife Refuge | -4 |
| Prudhoe Bay/Arctic Coastal Plain | 1 |
| State Wide Average | -14 |

## Wetland Characterization with Microwave Remote Sensing

**Inundation Monitoring with AMSR-E and MODIS**

**Wetland Characterization with Microwave Remote Sensing**

**Construct for derivation of monthly inundation data sets, showing example products for the NEESPI domain. Algorithm input data sets include AMSR-E brightness temperature and polarization difference, topography, and MODIS-based leaf area index (LAI). An iterative unsupervised multivariate clustering approach is employed to identify potential inundated areas and the corresponding inundation fraction, and principal component analysis applied to differentiate critical features within the inundated regions. The derived data sets show monthly mean relative inundated area fraction. The algorithm is applied globally and shown here for the NEESPI region**

- K. McDonald

## R. Prinn

- Slope is 1.01, i.e., good agreement in spatial gradient.

- Large offsets (~8%), contamination by clouds, aerosols?

**Notes:**
Model simulated CH4 column burden has very similar spatial gradient as observed by SCIAMACHY, i.e., slope is 1.01. But our modeled CH4 column is ~8% higher than observed value. This could be caused by cloud/aerosol contamination. SCIA CH4 team suggested using retrieved CO2 as a proxy of cloud height, i.e., higher the CO2 column, lower the cloud.

## Ecosystem Change and Processes in the Northern Oceans

**Ecosystem Change and Processes in the Northern Oceans**

## Changes in Arctic Productivity

- Sea ice extent has dropped recently, especially in 2007
- Primary production increased by 27.5 Tg C yr-1 between 2003 and 2007
- Primary production increased by 35 Tg C yr-1 between 2006 and 2007
- 30% of the increase due to increased open water habitat

- Courtesy K. Arrigo

## Annual productivity in Arctic Regions

**In-flow shelf**

**Interior shelf**

**Out-flow shelf**

**Basin >500 m**

- _Annual productivity in Arctic Regions_
**Annual productivity is highly variable, driven**
**by open water area.**
**Chukchi Sea is the only region with a significant **
**positive trend.**

- _Patterns in Arctic Ocean Productivity: The 10 year SeaWiFS record _VHill, R Zimmerman, P Matrai, E Olson

## Impacts of Changes in Sea Ice on Northern Oceans

- Each 106 km2 loss of sea ice could increase annual production by 163 Tg C yr-1 (K. Arrigo)
- Complete loss of spring-summer ice could boost annual Arctic primary productivity by as much as 1300 Tg C yr-1 (3-fold higher than the 1998-2002 mean) (K. Arrigo)
- Loss of ice could cause a shift from ice-obligate to pelagic fauna (K. Arrigo)
- Will responses of DMS biogeochemistry of the Arctic Ocean in response to less sea ice result in a negative feedback to climate associated with increased aerosols?
- As the sea ice continues to decline, the location, timing, and species make-up of the blooms is changing, vastly decreasing the amount of food reaching the living things on the ocean floor. This radically changes the species make-up and populations of the fish and other marine life forms, with significant repercussions for fisheries (from SAP 4.3)

## Shifts in center of distribution for 45 taxa in SE Bering Sea, 1982-2006

**Shifts in center of distribution for 45 taxa in ****SE Bering Sea, 1982-2006**

## Ecosystem Change and Processes in the Southern Ocean 

**Ecosystem Change and Processes in the Southern Ocean **

## Dynamics of the Airborne Fraction

- Atmosphere
- [Airborne Fraction]

- Distribution (fraction)

- 1960

- 2000

- 1980

- 1970

- 1990

- Canadell et al. 2007

## Southern Annular Mode (SAM)

*GEOPOTENTIAL HEIGHT (m)*

*WINDSTRESS (dyne cm**-2**)*

_**Southern Annular Mode (SAM)**_
_**Regression Patterns**_

- Positive Southern Annular Mode (SAM) represents stronger lows over Antarctica and stronger highs over adjacent ocean, which results in higher winds.  Positive SAM has been linked to increasing [CO2] and decreasing stratospheric ozone.

## SAM and CO2 Flux Variability

*REGRESSION (mol m**-2 **yr**-1**)*

*CORRELATION*

_**SAM and CO2 Flux Variability**_

- NCAR CCSM (FGM)

- Positive SAM related to outgassing of CO2
- 			Lovenduski et al. 2007

## Stronger venting of “natural CO2” 

- Stronger venting of “natural CO2”

## Trends in spatially-integrated Southern Ocean CO2 fluxes

- 					Lovenduski et al. in press

## Changes in Southern Ocean Primary Productivity

- K. Arrigo

## Changes in Southern Ocean Primary Productivity

- Total annual production in waters south of 50°S averaged 1949±70.1 Tg C yr-1 between 1998 and 2006, approximately half that of previous estimates.
- The large but relatively unproductive pelagic province accounted for ~90% of Southern Ocean production.
- Surprisingly, production in the marginal ice zone was only slightly higher than in the pelagic province.
**Unlike the Arctic Ocean, there was no secular trend in either sea ice cover or annual primary production in the Southern Ocean during our nine-year study.**
**Interannual variability was most closely tied to changes in sea ice cover, although changes in sea surface temperature also played a role.  **
- Annual primary production could increase in the future as stronger winds increase nutrient upwelling.

- K. Arrigo

## Summary

**Summary**

##  How are responses of northern terrestrial ecosystems to climate change influencing the exchanges of CO2, CH4, water, and energy, particularly with respect to changes in precipitation minus evaporation? 

** ****Analyses of CO2 exchange need to consider physiological responses and responses to multiple disturbances in northern terrestrial ecosystems.**
** ****It is important to evaluate the integrated effects of multiple ecosystem responses on the climate system to understand whether the changes will act to mitigate or enhance climate change.**
** ****How will primary productivity of the northern oceans change with the continued loss of sea ice?**
**  ****Will changes in DMS biogeochemistry result in substantial negative feedback to climate warming in the Arctic?**
*** *****How are changes in sea ice influencing marine food webs, and what are the implications of these changes for fisheries?**
** ****How will primary production and CO2 exchange of the Southern Ocean respond to continued changes in climate?**
*** *****How will changes in ecosystem structure and function influence lifestyles of indigenous peoples?**