http://sbi.utk.edu

The Western Arctic Shelf-Basin Interactions (SBI) Project-Highlights 2006

SBI Arctic / global change SBI Arctic / global change project 2002-2004 mapproject 2002-2004 map

• intensive field studies during intensive field studies during the record summer sea ice the record summer sea ice retreatretreat• investigating production, investigating production, transformation and fate of transformation and fate of carbon at the shelf-slope carbon at the shelf-slope interface in the northern interface in the northern Chukchi and Beaufort SeasChukchi and Beaufort Seas• downstream of the downstream of the productive shallow western productive shallow western Arctic shelvesArctic shelves• prelude to understanding the prelude to understanding the impacts of a potential warming impacts of a potential warming of the Arcticof the Arctic

Overview Statement

Pacific Water entering through the Bering Strait Gateway and across shelf Pacific Water entering through the Bering Strait Gateway and across shelf

and northward into the Arctic Basin:and northward into the Arctic Basin:

• is the most productive region in the Arcticis the most productive region in the Arctic

• is undergoing the most significant environmental change (maximum ice is undergoing the most significant environmental change (maximum ice

retreat, potential ecosystem restructuring)retreat, potential ecosystem restructuring)

• critical physical, biogeochemical and biological fluxes interact in this critical physical, biogeochemical and biological fluxes interact in this

region, with ramification to the global systemregion, with ramification to the global system

• the ice retreat and oceanic heat flux are unprecedented in the modern the ice retreat and oceanic heat flux are unprecedented in the modern

observational record being driven by both local and remote forcingobservational record being driven by both local and remote forcing

• biologically-mediated carbon-transformation processes are critical to the biologically-mediated carbon-transformation processes are critical to the

regional carbon cycling and ultimately, to both regional and global carbon regional carbon cycling and ultimately, to both regional and global carbon

flux dynamicsflux dynamics

AtmosphericForcing

Shelf Carbon CycleBering Strait

Inflow

CarbonStorage

Sea Ice Cover

Solar Insolation

GlobalCirculation

Upper Trophics

Humans

ClimateFeedbacks

Examples of linkages between Shelf – Basin InteractionsExamples of linkages between Shelf – Basin Interactionsand the and the Arctic SystemArctic System

Land-hydrology-seainterface

Shelf-Basin Exchange

ARCARCSSS relevant issues related to warming in the western Arctic OceanS relevant issues related to warming in the western Arctic Ocean- ecosystem change, including whale migration / feeding habit changeecosystem change, including whale migration / feeding habit change- human aspects: native community subsistence and culturehuman aspects: native community subsistence and culture- increased human presence: new transportation routes, natural resource explorationincreased human presence: new transportation routes, natural resource exploration- potential global consequences of freshwater export from the Arctic Ocean- potential global consequences of freshwater export from the Arctic Ocean

Observed September sea ice extent 1979-2005Observed September sea ice extent 1979-2005

Rate of decline• 1979-2001: 6.5 % per decade• 1979-2005: 8 % per decade

96-05 trend ~21% per decade?96-05 trend ~21% per decade?96-05 trend ~21% per decade?96-05 trend ~21% per decade?

Significant and Significant and acceleratedaccelerated decrease in sea ice extent in decrease in sea ice extent in the late 1990s and 2000s. the late 1990s and 2000s.

Note that largest changes Note that largest changes are at inflows of Pacific / are at inflows of Pacific / Atlantic water into the Atlantic water into the Arctic Ocean and during Arctic Ocean and during SBI field programs.SBI field programs.

09/87 09/02 09/05

[Woodgate and Aagaard, GRL 2005]

• moorings at Bering Strait:moorings at Bering Strait:

• decrease salinity and increase decrease salinity and increase freshwater fluxfreshwater flux

• revised Bering Strait FW influx revised Bering Strait FW influx upwards from 1989upwards from 1989

• shelf-basin transport via advection, shelf-basin transport via advection, eddy formation, canyon transporteddy formation, canyon transport

Increased freshening of Pacific Inflow

Bering/Chukchi/Beaufort Sea

Marginal Ice Zone System

Fluxes of heat, salt, Fluxes of heat, salt, freshwater, nutrients freshwater, nutrients through Bering Strait through Bering Strait and their seasonal and their seasonal and inter-annual and inter-annual variability strongly variability strongly influence the influence the Western Arctic Western Arctic ecosystemecosystem

[Woodgate et al. 2005; [Woodgate et al. 2005; Clement et al. 2005]Clement et al. 2005]

[courtesy W. Maslowski]

HVWHS

EHS

BC

EB

Modeled Sea Surface (0-5 m) Salinity (ppt), Velocity (cm/s)and Sea Ice Concentration (% - red contours) -

Mean August 1979-1981

- Heat content of surface waters: above - Heat content of surface waters: above 50 m depth sufficient to melt 0(10-100 50 m depth sufficient to melt 0(10-100 cm) thickness of sea icecm) thickness of sea ice- Studies (both field and modeling) are - Studies (both field and modeling) are needed to understand effects of Pacific needed to understand effects of Pacific Water advection from Bering Strait into Water advection from Bering Strait into the Arctic Ocean and its effect on the the Arctic Ocean and its effect on the environmentenvironment

Increased Pacific water heat fluxes into the Arctic Ocean1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 20040

5

10

15

20

Monthly mean

Hea

t F

lux

(TW

)

Bering Strait (upper 120 m) heat flux (net direction is North)

2.331

Net Net (13-mo.) Mean

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 20040

1

2

3

4

Monthly mean

Hea

t F

lux

(TW

)

Chukchi Shelf Line (upper 120 m) heat flux (net direction is North)

0.142

Net Net (13-mo.) Mean

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

-0.05

0

0.05

0.1

0.15

Monthly mean

Hea

t F

lux

(TW

)

Wrangel To Basin (upper 120 m) heat flux (net direction is East)

0.003

Net Net (13-mo.) Mean

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004-1.5

-1

-0.5

0

Monthly mean

Hea

t F

lux

(TW

)

Canadian Archipelago (upper 120 m) heat flux (net direction is South)

-0.321

Net Net (13-mo.) Mean

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

-0.02

-0.01

0

0.01

Monthly mean

Hea

t F

lux

(TW

)

East Siberian Shelf Line (upper 120 m) heat flux (net direction is South)

0

Net Net (13-mo.) Mean

She

baS

heba

She

baS

heba

EBC – Aug 2002

- IncreasedIncreased modeled modeled northward heat flux northward heat flux off the Chukchi Shelf off the Chukchi Shelf correlatescorrelates with the with the recent ice retreat in recent ice retreat in the Western Arcticthe Western Arctic (cor. coef. = 0.7-08)(cor. coef. = 0.7-08)

[Courtesy of W. Maslowski][Courtesy of W. Maslowski]

[SBI Hydrography Data Team (Codispoti, Swift et al.)][SBI Hydrography Data Team (Codispoti, Swift et al.)]

[Courtesy of W. Maslowski][Courtesy of W. Maslowski]

66° 66°

68° 68°

70° 70°

72° 72°

74° 74°

-170°

-170°

-160°

-160°

-150°

-150°

-140°

-140°

0 %51 - 100 %11- 50 %0.1 - 10 %

Scale: 1:30114560 at Latitude 0°

Distribution of sediment-Distribution of sediment-laden ice (fraction of total laden ice (fraction of total ice area)ice area)(data at: www.joss.ucar.edu/cgi-(data at: www.joss.ucar.edu/cgi-bin/catalog/sbi_hly-02-01/researcbin/catalog/sbi_hly-02-01/research/index)h/index)

• • >100,000 km>100,000 km22 of sediment-laden sea ice (5-8 x 10 of sediment-laden sea ice (5-8 x 1066 t particulate export, highly significant for shelf t particulate export, highly significant for shelf budget)budget)• • Enhanced rafting due to changing sea-ice Enhanced rafting due to changing sea-ice regimeregime• • Impact on ice primary production and carbon Impact on ice primary production and carbon flux?flux?

[Eicken et al. in 2005]

Multiple rafting with sediment layers in lowersections

Sediment-laden Sea Ice

NCEP reanalysis forwestern Arctic

22 upwelling events between22 upwelling events betweenSeptember 2002 and May 2003! September 2002 and May 2003!

Diagnosing an upwelling event in the western Arctic: Cross-stream fluxes of mass and properties [R. Pickart et al.]

Atmospheric LinkagesWhich storms trigger upwelling?

Upwellingfavorable

Noupwelling

Primary production and optical findings in the SBI regionPrimary production and optical findings in the SBI region

• Barrow Canyon high productivity, reaching 8.8 g C Barrow Canyon high productivity, reaching 8.8 g C mm-2-2 d d-1 -1

• High particle export to slope, basin?High particle export to slope, basin?

System relevanceSystem relevance: High levels of colored dissolved : High levels of colored dissolved organic material (CDOM) were observed which organic material (CDOM) were observed which would increase energy absorption in the surface would increase energy absorption in the surface waters by 40% over clearest natural waters thus waters by 40% over clearest natural waters thus impacting on heating, albedo impact and positive impacting on heating, albedo impact and positive feedback to further ice meltfeedback to further ice melt

[Hill and Cota, 2005]

Sea Area (103 km2) Depth (m) PP (gC/m2 yr)

Barents 1512 200 20-200

White 85 56 25

Kara 926 131 30-50

Laptev 498 48 25-40

East Siberian 987 58 25-40

Chukchi 620 80 20-400

Beaufort 178 124 30-70

Lincoln 64 257 20-40

Shelf N. Can. Arc. Archipelago

146 338 20-40

Shelf NE Greenland

30 119 20-40

Shelf NW Svalbard

6 93 20-40

[E. Sakshaug 2004]

D ica rbo xy lic A c id s a s % o f To ta lF a tty A c id s

24 -m ethy lcho les t-5 ,24 (28)-e no l a s% o f To ta l S te ro ls

0

5

%

Organic markers can detail carbon sources to the Arctic Basin

[Harvey, Belicka and Macdonald]

-Bioavailable DOM is rapidly produced in shelf waters during spring  and summer and some of Bioavailable DOM is rapidly produced in shelf waters during spring  and summer and some of this DOM is transported to the basin this DOM is transported to the basin

- Rates of utilization of DOM are relatively low in shelf waters - Rates of utilization of DOM are relatively low in shelf waters - Terrigenous DOM is abundant in shelf and polar surface waters - Terrigenous DOM is abundant in shelf and polar surface waters - Terrigenous DOM discharged to the Arctic Ocean by rivers has a  modern radiocarbon age- Terrigenous DOM discharged to the Arctic Ocean by rivers has a  modern radiocarbon age

2.7

2.5

Dissolved Organic Carbon (DOC) Cycling in the Western Arctic

Canada Basin

CO2

56 Tg DOC

7.3

?

Annual fluxes Tg DOC

6.01.3

Terrestrial DOC new Marine DOC

•DOC is being lost while circulating in the Arctic Ocean and/orDOC is being lost while circulating in the Arctic Ocean and/or fluxes of DOC from river sources are being underestimatedfluxes of DOC from river sources are being underestimated•DOC in the Arctic Ocean is probably not as refractory as previously thought,DOC in the Arctic Ocean is probably not as refractory as previously thought, and sediments are a potentially important source of DOC to the Arctic Oceanand sediments are a potentially important source of DOC to the Arctic Ocean

Sediment community oxygen consumption (mmol O2 m-2 d-1) from 1984-2004

• an indicator of carbon supply to the underlying benthos, persistent patterns of carbon flux to sediments

• yet time series stations in “hot spots” (black box) indicate decline in carbon supply and benthic standing stock [Grebmeier et al. 2006, Science]

[Data maps from Grebmeier et al. 2006, Prog. Oceanogr., accepted]

Macrofaunal biomass (g C m-2) from 1977-2004

• identify “foot prints” of high carbon deposition and benthic biomass on the shallow continental shelves for time series investigations embedded in periodic process studies

Pelagic-benthic coupling: SBI I and II results

[Ashjian, Campbell, Plourde]

Zooplankton Grazing Impacts

•Zooplankton grazing impacts are primarily dependant on Zooplankton grazing impacts are primarily dependant on zooplankton biomass, which increases in summer but is still low zooplankton biomass, which increases in summer but is still low compared to other Arctic shelf regionscompared to other Arctic shelf regions•High primary production combined with low zooplankton High primary production combined with low zooplankton grazing results in strong benthic-pelagic coupling that supports grazing results in strong benthic-pelagic coupling that supports very high benthic biomassvery high benthic biomass

Large Horizontal Export of POM at BC

Barrow Canyon (BC) sectionBarrow Canyon (BC) section

[Bates et al., 2005a; Moran et al. 2005][Bates et al., 2005a; Moran et al. 2005]

Much of the productivity Much of the productivity occurring in this region occurring in this region of the Chukchi Sea of the Chukchi Sea shelf was:shelf was:-exported laterally, with exported laterally, with plumes of suspended plumes of suspended POM in the upper POM in the upper halocline observed off-halocline observed off-shelf extending into the shelf extending into the Arctic Ocean basin Arctic Ocean basin (Bates et al., 2005),(Bates et al., 2005),

or or - vertically exported to vertically exported to the sea floor (Moran the sea floor (Moran et et alal., 2005).., 2005).

LargeLargePOCPOC

LargeLargePONPON

LHWLHW

UHWUHW

Plan for SBI DSR 2nd volume-deadline fall 2006 (Eds. Grebmeier, Harvey and Stockwell)

SBI Special Issue One - 23 papers

SBI Datasets:SBI Datasets: 228 228 (+45)(+45)

Data TypeData Type:: Benthic Benthic 5454 Hydrography Hydrography 5959 Ice Ice 1111 Meteorology Meteorology 5555 Microbiology Microbiology 88 Mooring Mooring 33 Navigation Navigation 2222 Optics Optics 77 Plankton Plankton 1010 Production Production 55 Satellite Satellite 2323 Service – Bottle Service – Bottle 2121 Service – CTD Service – CTD 1616 Underway Underway 4848 Water Chemistry Water Chemistry 2020

CruiseCruise::

20042004 HLY-04-02 HLY-04-02 1212 HLY-04-03 HLY-04-03 1010 HLY-04-04 HLY-04-04 44 HX-290 HX-290 1(U)1(U)20032003 HLY-03-03 HLY-03-03 33 NBP03-04a NBP03-04a 1212 HX-274 HX-274 1(U)1(U) 2003-14 Helo 2003-14 Helo 00

20022002 HLY-02-03 HLY-02-03 6565 AWS-02-I AWS-02-I 77 HX-260 HX-260 1(U)1(U) HLY-02-01 HLY-02-01 6363

PhasePhase:: I I 4747 II II 181181

Password ProtectedPassword Protected: : 99 Phase I – Phase I – 00 Phase II – Phase II – 99 2002 Data – 2002 Data – 11Loaded < 1 yr – Loaded < 1 yr – 44 CTD/Bottle – CTD/Bottle – 77 Ship CD – Ship CD – 22

www.joss.ucar.edu/sbi

JOSS website statistics

• Mar. 2005: SBI Phase II and Phase III planning presentation made to ARCSS Mar. 2005: SBI Phase II and Phase III planning presentation made to ARCSS Committee; input requested (March 2006, Wash. DC)Committee; input requested (March 2006, Wash. DC)

• Oct. 2005: discussions with NSF and ARCSS Committee about SBI Phase III, letter Oct. 2005: discussions with NSF and ARCSS Committee about SBI Phase III, letter sent to ACsent to AC

• Nov. 2005: AC responds with support letter for SBI Phase III, plus guidanceNov. 2005: AC responds with support letter for SBI Phase III, plus guidance• Dec. 6, 2005: AGU informal evening meeting SBI Phase III planningDec. 6, 2005: AGU informal evening meeting SBI Phase III planning• Dec. 19, 2005: SBI PI online meeting, discussions SBI II results & Phase III planningDec. 19, 2005: SBI PI online meeting, discussions SBI II results & Phase III planning• Jan. 19, 2006: ARCSS Committee/SBI AC online meeting-Phase III planningJan. 19, 2006: ARCSS Committee/SBI AC online meeting-Phase III planning• Jan. 30, 2006: Open Community eTown Hall Meeting: SBI update/Phase III Jan. 30, 2006: Open Community eTown Hall Meeting: SBI update/Phase III • Feb. 9, 2006: letter from AC to SBI AC/PIs outlining their guidance for a SBI Phase Feb. 9, 2006: letter from AC to SBI AC/PIs outlining their guidance for a SBI Phase

III direction within the new ARCSS formatIII direction within the new ARCSS format• Feb. 22, 2006: Open Town Hall Meeting Phase III, Oceans Meeting, Honolulu, Feb. 22, 2006: Open Town Hall Meeting Phase III, Oceans Meeting, Honolulu,

HawaiiHawaii• Feb. 26-28, 2006: Final SBI Phase II PI meetingFeb. 26-28, 2006: Final SBI Phase II PI meeting

• Mar. 6, 2006: SBI AC and ARCSS program managers at NSFMar. 6, 2006: SBI AC and ARCSS program managers at NSF• Mar. 29, 2006: SBI AC presentation to AC on Phase III direction, Seattle, WAMar. 29, 2006: SBI AC presentation to AC on Phase III direction, Seattle, WA• NSF AO: ? Separate SBI Phase III or within larger ARCSS AO; release planned NSF AO: ? Separate SBI Phase III or within larger ARCSS AO; release planned

summer 2006, proposal deadline fall 2006, funding 2007 during period of summer 2006, proposal deadline fall 2006, funding 2007 during period of International Polar Year (IPY) 2007-2009International Polar Year (IPY) 2007-2009

SBI Phase III Planning Timeline

ARCSS/SBI Phase IIIIntegration, Synthesis and Modeling

ARCTIC CARBON CYCLING AND SHELF-BASIN DYNAMICS

1.1. What are the important linkages between processes in the Western What are the important linkages between processes in the Western Arctic shelf-basin ecosystem(s) and the larger Arctic system? Arctic shelf-basin ecosystem(s) and the larger Arctic system? What are the ramifications for the global ocean and climate?What are the ramifications for the global ocean and climate?

2.2. How will the large and interconnected changes recently observed How will the large and interconnected changes recently observed in the western Arctic margins propagate through natural and human in the western Arctic margins propagate through natural and human systems in the Arctic and sub-Arctic? How do these recent changes systems in the Arctic and sub-Arctic? How do these recent changes compare to the past?compare to the past?

3. 3. How does climate variability over multiple time scales influence How does climate variability over multiple time scales influence the coupled physical, chemical, and biological processes over arctic the coupled physical, chemical, and biological processes over arctic shelf/basin systems? How do changes in these?shelf/basin systems? How do changes in these?

Overarching Themes and QuestionsOverarching Themes and Questions

1. Although the Western Arctic appears to play a disproportionately large role in 1. Although the Western Arctic appears to play a disproportionately large role in the dynamics of pan-Arctic system, there is a growing need to integrate and the dynamics of pan-Arctic system, there is a growing need to integrate and synthesize data and processes linking climate forcing, element and heat synthesize data and processes linking climate forcing, element and heat fluxes through the Bering Strait gateway, and shelf / basin carbon cycling in fluxes through the Bering Strait gateway, and shelf / basin carbon cycling in the Western Arctic with the broader Arctic system. Relevant studies might the Western Arctic with the broader Arctic system. Relevant studies might include:include:

Determine the most significant and critical changes to the Arctic system documented in the Determine the most significant and critical changes to the Arctic system documented in the modern data recordsmodern data records

Investigate forcing connectivity by the atmosphere, land and ocean on shelf-basin exchange Investigate forcing connectivity by the atmosphere, land and ocean on shelf-basin exchange through a range of spatial and temporal scalesthrough a range of spatial and temporal scales

Evaluate the impacts of seasonal sea ice extent and its variability on high productivity Evaluate the impacts of seasonal sea ice extent and its variability on high productivity ecosystems, circulation, and shelf-basin interactions, and ecosystems, circulation, and shelf-basin interactions, and

Understand how shelf-basin and inter-basin exchanges communicate change over larger Understand how shelf-basin and inter-basin exchanges communicate change over larger Arctic system scales.Arctic system scales.

How will the large and interconnected changes observed on the western Arctic shelf and How will the large and interconnected changes observed on the western Arctic shelf and margin affect and propagate through the larger Arctic and subarctic natural and human margin affect and propagate through the larger Arctic and subarctic natural and human environment and how do they compare to past changes?environment and how do they compare to past changes?

How does climate variability over decadal to millennial scales influence oceanographic, How does climate variability over decadal to millennial scales influence oceanographic, biogeochemical, and biological processes over arctic shelf/basin systems, and how do these biogeochemical, and biological processes over arctic shelf/basin systems, and how do these processes influence the broader arctic system? processes influence the broader arctic system?

Subthemes and Questions:

2. There is a dynamic barrier at the continental shelf /slope margin, resulting in 2. There is a dynamic barrier at the continental shelf /slope margin, resulting in sharp physical and biological gradients. Understanding the influence of the sharp physical and biological gradients. Understanding the influence of the shelf break barrier on physical and biological processes is crucial for shelf break barrier on physical and biological processes is crucial for evaluating past system states and predicting future change impacts. evaluating past system states and predicting future change impacts. Relevant studies might include:Relevant studies might include:

What processes maintain the sharp gradient between the most productive shelves adjacent to What processes maintain the sharp gradient between the most productive shelves adjacent to the least productive basin in the world’s ocean?the least productive basin in the world’s ocean?

How are shelf transformation products (salt, nutrients, carbon, zooplankton) fluxed across How are shelf transformation products (salt, nutrients, carbon, zooplankton) fluxed across the shelfbreak into the basin?the shelfbreak into the basin?

What processes on this productive shelf are critical for the tight benthic-pelagic coupling, What processes on this productive shelf are critical for the tight benthic-pelagic coupling, which supports an incredible biomass of marine mammals that in turn are dependent upon which supports an incredible biomass of marine mammals that in turn are dependent upon by Native populations for their subsistence and cultural identity? by Native populations for their subsistence and cultural identity?

How are these processes similar/different to continental margins in other arctic regions How are these processes similar/different to continental margins in other arctic regions and/or continental margins in other regions of the world’s oceans?and/or continental margins in other regions of the world’s oceans?

How will ongoing environmental changes modify the dynamic barrier between the shelf and How will ongoing environmental changes modify the dynamic barrier between the shelf and basin?basin?

Subthemes and Questions:

3. Variation in ice cover and thickness, mediated by solar insolation and 3. Variation in ice cover and thickness, mediated by solar insolation and advected heat flux through Bering Strait, initiate a local to system-wide advected heat flux through Bering Strait, initiate a local to system-wide cascade of changes in arctic physical and biogeochemical processes that are cascade of changes in arctic physical and biogeochemical processes that are influenced strongly by oceanographic and biological processes over western influenced strongly by oceanographic and biological processes over western Arctic shelves. Predicted future Arctic system changes include reduced sea Arctic shelves. Predicted future Arctic system changes include reduced sea ice, increased freshwater fluxes, higher air and sea temperatures, longer ice, increased freshwater fluxes, higher air and sea temperatures, longer growing seasons, and permafrost thaw. Consequences of such changes will growing seasons, and permafrost thaw. Consequences of such changes will impact food web structure, trophic efficiency, sediment impact food web structure, trophic efficiency, sediment mineralization/sediment oxidation state, benthic biomass, and carbon export mineralization/sediment oxidation state, benthic biomass, and carbon export and sequestration into the Arctic Basin. Relevant research topics might and sequestration into the Arctic Basin. Relevant research topics might include: include:

How will the timing and extent of predicted future changes impact carbon cycling of the How will the timing and extent of predicted future changes impact carbon cycling of the Arctic shelf system? Arctic shelf system?

How will the arctic system respond to ice retreat beyond the shelf break?How will the arctic system respond to ice retreat beyond the shelf break?What is the strength and variability of the linkages between important environmental What is the strength and variability of the linkages between important environmental

controls of the arctic system (climate/physical oceanography) and ice cover, ocean biology controls of the arctic system (climate/physical oceanography) and ice cover, ocean biology and other elements of the arctic system (other dimensions)? and other elements of the arctic system (other dimensions)?

How will these linkages change in the future?How will these linkages change in the future?What are the consequences for the Arctic system (carbon, climate, human resource use)?What are the consequences for the Arctic system (carbon, climate, human resource use)? How will increased natural resource exploitation in the region impact shelf and slope How will increased natural resource exploitation in the region impact shelf and slope

ecosystem dynamics?ecosystem dynamics? How will an increased flux of heat through Bering Strait influence clathrate erosion?How will an increased flux of heat through Bering Strait influence clathrate erosion?

Subthemes and Questions:

4.4. Changing climate may alter the dynamics of pelagic and benthic arctic Changing climate may alter the dynamics of pelagic and benthic arctic systems, with possible mode shifts in their structure and productivity. systems, with possible mode shifts in their structure and productivity. Relevant studies might include:Relevant studies might include:

How do changes in carbon cycling and pelagic-benthic coupling in the arctic system, driven How do changes in carbon cycling and pelagic-benthic coupling in the arctic system, driven by environmental change, influence the structure of arctic food webs and the population by environmental change, influence the structure of arctic food webs and the population dynamics of important producer and consumer groups?dynamics of important producer and consumer groups?

How will these changes affect Native communities that depend on the current ecosystem How will these changes affect Native communities that depend on the current ecosystem state for their subsistence and cultural identity?state for their subsistence and cultural identity?

How will future climate warming affect the production and export of carbon in arctic How will future climate warming affect the production and export of carbon in arctic environments and the dynamics of arctic biological communities? environments and the dynamics of arctic biological communities?

How will bottom-up versus top-down controls of arctic biological systems respond to How will bottom-up versus top-down controls of arctic biological systems respond to

changing arctic ice and climatic conditions?changing arctic ice and climatic conditions?

Subthemes and Questions:

Comments and suggestions?