Characteristics of Nordic Marine Ecosystems Ken Drinkwater Barents - - PowerPoint PPT Presentation

Characteristics of Nordic Marine Ecosystems

Ken Drinkwater

NCoE Research Training Course Effect Studies and Adaptation to Climate Change May 8, 2012

Barents Sea: 1.4x106 km2, Mean depth 230 m

Lofoten Basin Norwegian Basin

Norwegian Sea: 1.1x106 km2 Mean depth 1800 m

Barents Sea

Mean Conditions: Physical Oceanography

Circulation

Atlantic Inflow to the Barents Sea is on average approximately 40% that of the flow in Norwegian Sea.

Rey & Mork, Toktrapport, HI, 2003

Salinity Temperature Extended Gimsøy Section - May/June 2003

Hydrographic Transect Across Norwegian Sea

400 m Salinity 0 m 40 km

Norwegian Sea Arctic Front

Density Compensating (Passive) Fronts

June 2007 CTD data T S σθ Strong T,S contrast Weak density contrast

Drinkwater et al., in prep.

Red represents Atlantic Water inflow, blue the Arctic Waters and green is the extension of the Norwegian Coastal Current and is shelf water of lower

• salinity. The division

between Atlantic and Arctic Waters is the Polar Front.

Barents Sea Circulation

Arctic/Polar Waters Coastal Waters Barents Sea Waters Atlantic Waters

Mean at 100 m

Barents Sea Temperatures

The Fugloya- Bjørnoya Section has had seasonal hydrographic sections taken since the 1970s while current meters have been moored for over 10 years and are continuing.

Barents Sea Opening (BSO)

Weak Surface T contrast Polar Front (50-150 m)

• Strong T, S, contrast
• Weak density contrast
• Evidence of interleaving

90 km

Strong Surface S Front T S σθ

Density Compensating (Passive) Fronts

Barents Sea Polar Front

August 2007 CTD data Storbanken

Våge et al., 2012

Ice coverage in different months

70°N 75°N 80°N 10°E 2 ° E 30°E 40°E 50°E 60°E 7 ° E

Ocean Data View

II IV VI X XII IX XI

Sea Ice

Mean Conditions: Biology

Annual production: Barents Sea ~90-150 g C m-2, Atlantic 2-3x Arctic Norwegian Sea ~80-180 g C m-2

Primary Production

Norwegian Sea June 2007 Barents Sea August 2007

Phytoplankton Biomass

Arctic Front Atlantic Atlantic Front Arctic

South North West East

Norwegian Sea Iceland Sea Jan Mayen

Jan Mayen Ridge

There is no increased phytoplankton biomass or production at the fronts.

Erga et al., submitted Basedow, pers. com.

Norwegian Sea Norwegian Shelf/Barents Sea Ocean circulation and climate

Modified after M. Heath

Zooplankton – Calanus finmarchicus

Main Zooplankton Species

• C. finmarchicus, 1-yr
• C. glacialis, 2-yr

Temperature at 50 m

Hamre 1999

Major Fish Species

Capelin Herring

Hamre 1999

Atlantic Cod

Polar Cod

Estimated annual biomass, production and consumption of different trophic levels.

Loeng & Drinkwater 2007

Interannual Variability

Air Temperature Variability

Significant warming has occurred twice in the past 100+ years in Northern Hemisphere: 1920-1950s and 1990s to present.

Johannesen et al., 2004

Inter-annual variations in Atlantic water

• trend since 1970s
• inter-annual variations
• anomalies trough the

system, in general not dampened.

Skagseth et al. 2008

Volume flux

Fugløya-Bear Island Vardø-N

Temperature anomalies

Observations in BSO

• 0.15
• 0.05

0.05 0.15 1965 1975 1985 1995 2005

Salinity Anomaly Sea Surface Salinties Western Barents Sea

Salinity increases due to transport from the south providing further evidence of importance of advection.

Salinity Anomaly Time Series and Trends

Positive Phase of NAO

• deeper Low over Iceland, stronger

High over the Azores

• more northerly storm track
• Warmer, wetter in northern Europe

Negative Phase of NAO

• weaker Low over Iceland, weaker High
• ver the Azores
• weaker storms, move southerly
• Colder dryer in northern Europe

North Atlantic Oscillation (NAO)

• M. Visbeck, CLIVAR Website

Effects of the NAO

• 8,00
• 6,00
• 4,00
• 2,00

0,00 2,00 4,00 1958 1963 1968 1973 1978 1983 1988 1993 1998 Year, longitude of 35 PSU

NAO winter index

• 8
• 6
• 4
• 2

2 4 6 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year, NAO

Longitude NAO 6S

Winter NAO index (Hurrell. 1995) and the westerly penetration of Atlantic water along 65o45´N. From Blindheim et al. (2000).

Blindheim et al. (2001)

High NAO Low NAO

Atlantic Multidecadal Oscillation (AMO)

Sutton and Hodson, 2005

Barents Sea (Kola Section) Temperatures

2.5 3.0 3.5 4.0 4.5 5.0 5.5 1890 1940 1990 Temperature (°C) Annual Mean Decadal Multidecadal

Data kindly provided by PINRO

Month

1900 1920 1940 1960 1980 2000

Jan Mar May Jul Sep Nov

Barents Sea (Atlantic sector) Barents Sea (Arctic sector)

Jan Mar May Jul Sep

1900 1920 1940 1960 1980 2000

Jan Mar May Jul Sep Nov

anomalies 1900-2006

Heat in the Barents Sea due mostly to advection rather than air-sea heat exchange.

R2 = 0.24 1900-2001 2.5 3.0 3.5 4.0 4.5 5.0

• 5

5 10 15 20 25 30 35 40

NAO Temperature (°C)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Last year of 30-year Period Correlation Coefficient

Kola-NAO Correlations

General positive relationship The strength of the relationship has changed over time and during the 2000s is near its maximum.

• 40
• 30
• 20
• 10

10 20 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year Sea Ice coverage anomaly, %

Sea Ice Cover Anomalies

Barents Sea (1982-2006) Decadal scale variability determined by advection of heat forced by storms coming across Atlantic. Short time scale variability determined by storms crossing the Arctic that advect ice into the Barents Sea.

• Standardized anomalies based on 40 time series of

meteorological, sea-ice and oceanographic conditions

• Up to late 1990s out of phase relationship which are

now in phase. This is related to changing atmospheric patterns.

Drinkwater et al., submitted NORCAN

Effect of Warming on primary production, 1998-2006

2 4 6 8 10 200 300 400 500

Annual mean SST (°C)

Total annual net primary production (gC m-2)

Barents Sea (P = 0.093) Norwegian Sea (n.s.) Bering Sea (P = 0.039) Gulf of Maine / Georges Bank (P < 0.001) Gulf of Alaska (n.s.)

Mueter et al. 2009

NW Barents Sea

Krill Abundance Indices

Southern Barents Sea

Norwegian Sea Zooplankton, g/m2

2000 2009

Norwegian Sea Fish Catches

Barents Sea

Sea Around Us Project

Development of stocks in the Norwegian Sea

2 4 6 8 10 12 14 16 18 20 5 10 15 20 25 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Plankton, g /m2 Pelagic fish, million tonnes

Mackerel Herring Blue whiting Plankton

Blue Whiting Growth

Barents Sea Fish Catches

Barents Sea

Sea Around Us Project

Variation in fish populations

0-group fish (1980-2006)

Eastward shift in distribution

Coast Aug Kola Aug FB Aug FB Mar cod capelin herring haddock

1987 2004 cod herring capelin

0-group fish

• 1987 was a cold year
• 2004 was a warm year
• More and further east/north

PS 2006 (also warm)

haddock

2003 2006 2005 2004

Invasive Species

Snake Pipefish

Seabirds

Future Changes?

Ice algae

• With the reduction
• f sea ice, ice

algae will decline in abundance and those animals feeding on ice algae will also

• decline. This will

change the structure and functioning of Arctic ecosystems.

Future zooplankton production -Barents Sea

2045-2054 1995-2004

Production increases in Atlantic Waters

Ellingsen et al. (2008)

Production decreases in Arctic Waters

Highly likely to be a general northward movement in response to climate changes (already

• ccurring!)

Shifts in Fish Distribution

Capelin Spawning in Response to Climate Change

Huse and Ellingsen, 2008

Present Spawning Future Spawning Direction of distributional shift of adult feeding migration

Year 1 Year 30 Year 20 Year 10

Likely Polar cod retreats from subarctic into the Arctic

Chung et al., 2008, UBC Report

Cod Recruitment and Temperature

Mean Annual Bottom Temperature

11 10 9 8 7 6 4 3 2

Temp Warm Temperatures decreases Recruitment Warm Temperatures increases Recruitment Recruits

Planque and Fredou (1999)

R2 = 0.75

• 1.5
• 1
• 0.5

0.5 1 1.5 2 2 4 6 8 10 12 Bottom Temperature d(Recruitment)/dT

If BT < 5° and T warms stock recruitment generally increase If BT between 5° and 8.5°C little change in recruitment If BT >8.5°C recruitment generally decreases If BT 12°C we do not see any cod stocks GB

Effect on abundance of 1°C increase

Increase No change Decrease Collapse ?

1 to 2°C Temperature Increase

Increase No change Decrease Collapse ?

2-3°C Temperature Increase

Increase No change Decrease Collapse ?

3-4°C Temperature Increase

Increase No change Decrease Collapse ?

Ice-Dependent Marine Mammals

Polar Bear Minke Whales

• Highly likely polar bear abundances will decrease

and distribution will follow the ice out of the Barents

• Whale abundance and distribution (especially Minke

whales) will likely increase.

Food web in Atlantic water Food web in Arctic water

Changes in ecosystem function (Barents)

The food web changes may be far more dramatic for the higher compared to the lower trophic levels

Falk-Petersen et al. 2007

There is the possibility that boreal species from the Arctic and Pacific will move into the Arctic and may start to mix.

Summary

• Strong warming primarily due to advective

heat fluxes

• Traditional NAO forcing less important
• Zooplankton increasing slightly in Barents,

declining in Norwegian Sea

• Cod and haddock in Barents doing very well,

capelin variable but presently increasing

• Norwegian Sea, pelagics have been at very

high abundance but appear to be decreasing in recent years, perhaps due to reduced zooplankton.

Thank you for your attention!

Comparision between BSO and Svinøy section

Blue Whiting in Norwegian Sea

Blue whiting stock-recruitment relationship

0e+00 2e+06 4e+06 6e+06 8e+06 0e+00 2e+07 4e+07 6e+07 SSB (tonnes) Recruitment (000s of individuals)

81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07

Role of Subpolar Gyre

(Hatun et al. 2009)

Hátún et al., 2009 Strong gyre, colder

• ver Rockall Plateau

(RP), lower recruitment Weak gyre, warmer

• ver Rockall Plateau

(RP), higher recruitment

Variations in predation by mackerel on eggs and larvae

Blue Whiting distribution during cold years Blue Whiting distribution during warm years

Development of stocks in the Norwegian Sea

2 4 6 8 10 12 14 16 18 20 5 10 15 20 25 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Plankton, g /m2 Pelagic fish, million tonnes

Mackerel Herring Blue whiting Plankton