1. Department of Environmental Earth System Science Stanford University
Investigations into the biology and biogeochemistry of a rapidly changing Arctic Ocean
Kevin R. Arrigo
Department of Environmental Earth System Science Stanford University

2. Background Circulation influenced by both Atlantic and Pacific waters
Atlantic (red):
Warm, salty, low
nutrient, deep
Pacific (blue):
Cold, fresh, high
nutrient, shallow
Cold halocline
layer restricts
influx of nutrients
from depth

3. Background Extensive continental shelves (53% of area)
- Highly productive
Large input of fresh-water from rivers
Relatively low surface water nutrients
High nutrients in deep basins
Bathymetry (m)

4. Background Sea ice dynamics are important Maximum ice extent
Minimum ice extent

5. Background Sea ice dynamics are important
Decreasing trend in summer minimum ice cover
~20% drop

6. Changes in Arctic Sea Ice Cover
Summer minimum sea ice cover dropped dramatically in 2007 and 2008
2008
2007

7. Changes in Arctic Sea Ice Cover
2006
2007
Difference ( )
Large area of Arctic Ocean was exposed for first time
Approximately 1.3 x 106 km2 (area in red)
New ice-free pelagic habitat
Arrigo et al. (GRL, 2008)

8. Given ongoing changes in the Arctic Ocean… How has primary production changed in recent years?

9. Background How primary production was calculated
Algorithm modified from Southern Ocean (Arrigo et al. 2008, Pabi et al. 2008)
Based on remotely sensed SST, Chl a, and sea ice
Forced with winds, cloud cover, and solar radiation

10. Background
How did primary production in the Arctic vary prior to 2007?
Tg C yr-1 from
(Pabi et al. 2008)
Non-significant
increase in annual
primary production
1998 within 10% of Sakshaug (2003): 329 Tg C yr-1
Pabi et al. (JGR, 2008)

11. Changes in Arctic Productivity
How has Arctic primary production changed since 2006?
Annual
Primary 459 Tg C 544 Tg C 480 Tg C
Production
2007 and 2008 are the most productive years on record
Between 2006 and 2007, production increased by >15%
Only 30% of this increase was due to
increased open water habitat in 2007
(Arrigo et al., GRL 2008)

12. Changes in Arctic Productivity
70% of 2007 increase in primary production related to longer growing season

13. Spatial Changes in Arctic Productivity
Annual production
Mean
(Tg C yr-1)
Largest increase
In :
Beaufort, Chukchi,
East Siberian, Laptev
(25-75%) 36 41 23 48 63 26
136
127

14. Temporal Changes in Arctic Productivity
These 4 sectors also exhibited the largest interannual differences in the timing of the spring bloom over the last 3 years
39 days
27 days
26 days
48 days

15. Temporal Changes in Arctic Productivity
Related to changes in the timing of increase in open water area
How will organisms respond to changes in the timing of the spring bloom?
21 days
31 days
40 days
28 days

16. Changes in Arctic Productivity
Annual primary production increased by 140 Tg C yr-1 between 1998 and 2008 (statistically significant trend)
A 40% increase over the last decade
Unexpected given
presumed nutrient
limitation
Largest increases
on continental
shelf
Is this sustainable?
Nutrient source?

17. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Where?
Beaufort/Chukchi Sea
Continental shelf
Canada Basin
When?
Spring/Summer 2010 & 2011
30-45 day cruises
Depending on ship used (Healy or Amundsen)
Depending on science priorities

18. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Who?
NASA Ocean Biol. and Biogeochem.
NASA Cryosphere program
Possibly NSF and Canadians
How much?
NASA OBB: awards, ~$2 million/yr
NASA Cryosphere program: 1-2 awards, ~$500K/yr

19. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Central science question:
What is the impact of climate change (natural and anthropogenic) on the biogeochemistry and ecology of the Chukchi and Beaufort seas?

20. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Related issues and example questions:
A. Characterize and quantify the interactions and feedbacks of water and sea ice photobiology and photochemistry with above-water, in-water, and ice radiation fields and their effect on ocean and sea ice biology, ecology, and biogeochemistry.
Example questions include:
What impact does changing atmospheric composition (e.g., clouds, aerosols) and surface albedo have on PAR and UV radiation, and how does this influence ocean productivity and biogeochemistry?

21. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Related issues and example questions:
A. Characterize and quantify the interactions and feedbacks of water and sea ice photobiology and photochemistry with above-water, in-water, and ice radiation fields and their effect on ocean and sea ice biology, ecology, and biogeochemistry.
Example questions include:
What are the (seasonal) relationships between algal and bacterial metabolism with above-water, in-water, and ice radiation fields (apparent and inherent optical properties)?

22. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Related issues and example questions:
A. Characterize and quantify the interactions and feedbacks of water and sea ice photobiology and photochemistry with above-water, in-water, and ice radiation fields and their effect on ocean and sea ice biology, ecology, and biogeochemistry.
Example questions include:
What are the pathways of optically active dissolved organic matter in land, water, and sea ice, as detailed by optical and chemical observations, and their effect on land, sea, and sea ice biogeochemical interactions?

23. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Related issues and example questions:
A. Characterize and quantify the interactions and feedbacks of water and sea ice photobiology and photochemistry with above-water, in-water, and ice radiation fields and their effect on ocean and sea ice biology, ecology, and biogeochemistry.
Example questions include:
What is the distribution, community composition and activity of microbial communities associated with the biologically-mediated, climate-related exchange processes between the Arctic Ocean, cryosphere, and atmosphere?

24. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Related issues and example questions:
A. Characterize and quantify the interactions and feedbacks of water and sea ice photobiology and photochemistry with above-water, in-water, and ice radiation fields and their effect on ocean and sea ice biology, ecology, and biogeochemistry.
Example questions include:
• How do changing sea ice conditions and radiation impact changes in biological oceanography (e.g., phytoplankton, zooplankton, fisheries) and biogeochemistry, such as changes in emissions of radiatively active gases?

25. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Related issues and example questions:
B. Understanding the mechanisms controlling the fluxes of CO2, CH4, DMS, and other radiatively or biologically important gases, under different sea ice conditions, surfactants, meteorological conditions, and upper ocean turbulence regimes.
Example questions include:
• What will be the effect of a change in the strength of the biological pump due to sea ice, land, and ocean interactions (e.g., nutrients, dissolved inorganic carbon, DIC) on the air-sea flux of CO2?

26. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Related issues and example questions:
B. Understanding the mechanisms controlling the fluxes of CO2, CH4, DMS, and other radiatively or biologically important gases, under different sea ice conditions, surfactants, meteorological conditions, and upper ocean turbulence regimes.
Example questions include:
• How are gas fluxes affected by the radiation field, sea ice and riverine input, first year vs. multi-year sea ice fields, cycling of DOM and CDOM, changes in emperature, DIC and alkalinity, permafrost thawing, and other land-sea interactions?

27. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Related issues and example questions:
B. Understanding the mechanisms controlling the fluxes of CO2, CH4, DMS, and other radiatively or biologically important gases, under different sea ice conditions, surfactants, meteorological conditions, and upper ocean turbulence regimes.
Example questions include:
• How do the in-water, air-sea, and through-ice biogenic fluxes of CO2, CH4, and other climatically relevant gases compare under varying sea ice radiation fields?

28. Cruise Track Will depend on what proposals are funded
Will sample both open water and sea ice

29. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Core measurements:
Hydrography
Vertical profiling by CTD
Vertical profiling by XBT, XCTD
Salinity, alkalinity, dissolved oxygen, and inorganic nutrients
Phytoplankton
Phytoplankton pigments (Horn Point)
Biomass (POC, PON, cell size, cell number)
14C Primary Productivity

30. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Data Synthesis, Assimilation, and Modeling:
NASA seeks focused, multi-scale data assimilation experiments and model/forecast validation studies in the Chukchi and Beaufort Seas study area that include sea ice, ocean, atmosphere, and ecological components

31. Investigations of Climate and Environmental Change on Arctic Pacific Shelves (ICECAPS)
Data Policy:
All data collected will be subject to the standard NASA Earth Science data policy (
Data collected are required to be submitted to the NASA SeaBASS archive within one year of collection.
Proposal Due Date
June 1, 2009