Investigations into the biology and biogeochemistry of a rapidly changing Arctic Ocean

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

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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)
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Background

• Sea ice dynamics are important

Maximum ice extent
Minimum ice extent
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Background

• Sea ice dynamics are important
• Decreasing trend in summer minimum ice cover
• 20 drop

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Changes in Arctic Sea Ice Cover
Summer minimum sea ice cover dropped dramatically
in 2007 and 2008
2008
2007
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Changes in Arctic Sea Ice Cover
2007
2006
Difference (2006-2007)

• 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)
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Given ongoing changes in the Arctic OceanHow
has primary production changed in recent years?
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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

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Background

• How did primary production in the Arctic vary
  prior to 2007?

• 356-459 Tg C yr-1 from 1998-2006
• (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)
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Changes in Arctic Productivity

• How has Arctic primary production changed since
  2006?
• 2006 2007 2008
• 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
  gt15
• Only 30 of this increase was due to
• increased open water habitat in 2007
• (Arrigo et al., GRL 2008)

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Changes in Arctic Productivity

• 70 of 2007 increase in primary production
  related to longer growing season

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Spatial Changes in Arctic Productivity
Annual production Mean 2006-08 (Tg C
yr-1) Largest increase In 2007-2008 Beaufort
, Chukchi, East Siberian, Laptev (25-75)
36
41
23
48
63
26
136
127
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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
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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
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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?

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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

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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 5-12 awards, 2 million/yr
• NASA Cryosphere program 1-2 awards, 500K/yr

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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?

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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?

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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)?

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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?

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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?

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

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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
  (http//nasascience.nasa.gov/earth-science/earth-s
  cience-data-centers/data-and-information-policy/).
  
• Data collected are required to be submitted to
  the NASA SeaBASS archive within one year of
  collection.
• Proposal Due Date
• June 1, 2009