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

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

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)

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

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

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

Changes in Arctic Sea Ice Cover 2006 2007 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)

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

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

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)

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 >15% Only 30% of this increase was due to increased open water habitat in 2007 (Arrigo et al., GRL 2008)

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

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

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

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

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?

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

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

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?

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?

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)?

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?

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?

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?

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?

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?

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?

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

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

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

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-science-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