Northern Bering Sea 2007
PI's: Jackie Grebmeier and
Lee Cooper, University of Tennessee
James Lovvorn, University of Wyoming, Laramie WY
We completed two cruises in the Bering Sea during summer 2007:
Sir Wilfrid Laurier cruise.July10 - July 21 2007, Victoria to Dutch Harbor to Barrow
Short video and sound podcasts (use i-Tunes, Window Media Player, Real Player or other media software to play)
Peter Lane (University of Charleston) explains his research aboard the ship
Polar bear seen from ship while sampling in Barrow Canyon
Walruses on ice in Barrow Canyon
Lee Cooper talks with high school teacher Betty Carvellas about her work onboard the Laurier as part of the benthic sampling team (sound only .mp3 file)
Lee Cooper talks with Deutchlandfunk (German public radio) reporter Monica Seynsche about her public outreach efforts on ship (sound only .mp3 file)
More information on the Sir Wilfrid Laurier cruise and associated links
USCGC Healy (HLY0702-SLIPP07): May 16 - June 18 2007, Dutch Harbor to Dutch Harbor
Educational and Public Outreach products:
Janet Warburton's journal entries (PolarTREC program providing
research experiences for educators in the Arctic and Antarctic
during International Polar Year)
Podcasts now available froim Polar Palooza, an International National Polar Year program of Passport to Knowledge
"Panel Limits Northern Bering Sea Bottom Trawling" or download pdf version. Copy of article from the Anchorage Daily News describing new limits placed on northern Bering Sea trawling in June 2007. Principal investigators Cooper, Grebmeier and Lovvorn wrote a letter transmitted off the ship to the North Pacific Fisheries Management Council supporting protection of the rich benthic communities of the northern Bering Sea from industrial trawling.
Supported (other research groups using the ship)
National Marine Mammal Lab Research Efforts on NBS 2007 cruise
Documents provided as part of the cruise planning process:
HLY0702 Cruise Plan
HLY0702 USCG Questionaire (pdf)
Climate-Driven Change in
Impacts of Benthic Predators in the Northern Bering Sea
A. PROJECT SUMMARY
Perhaps the most striking evidence of global climate change is decreased extent of arctic sea ice and recent studies indicate this is occurring now south of St. Lawrence Island (SLI) in the SLI polynya region (SLIP). Despite research on the consequences of sea-ice change for physical oceanography and weather, effects on arctic marine food webs from microbes to top predators are by comparison very poorly understood. Our field research will investigate a major mechanism by which sea-ice change might affect the very productive, benthic-dominated food webs on shallow arctic shelves -expansion of the ranges and numbers of mobile benthic predators owing to increased temperature of bottom water. When winter sea ice melts on the north-central Bering Sea shelf, a pool of cold bottom water (<1°C) forms that persists through summer and reduces the numbers and growth of crabs and groundfish. The size of the cold pool decreases with decreasing ice extent. This area is currently the sole wintering site of the world population of the benthic-feeding Spectacled Eider (SPEI), a principal top predator. Expansion of competing crab and fish predators as ice cover declines and the cold pool contracts may affect food availability for the eiders. In this project, our main questions are:
Question 1: Is the benthic food web in the north-central Bering
Sea limited by top-down control by predators?
We will collect data needed to model the total impact of predators on their main benthic prey in the northcentral Bering Sea. These predators include SPEI, groundfish, snow crabs, sea stars, and gastropods.
Question 2: Are the overwinter survival and/or prebreeding
condition of SPEI being impacted by climate driven trends in ice
cover that are allowing populations of competing crabs and
groundfish to expand?
We will use past and current data to simulate impacts on the energy balance of the main endotherm predator (SPEI) of variations in crab and groundfish populations expected to occur with changes in ice cover and resulting temperature of bottom water.
Question 3: Are the time-series benthic system changes observed
south of St. Lawrence Island continuing and are they forced by
bottom-up (hydrographic) or top-down (predator) interactions, or
We will continue a long-term (1950-2005) record of benthic communities and carbon cycling processes in this area, which is essential to analyses in this project. These data will also indicate whether declines in organic matter supply to sediments that we have measured at a subset of stations have occurred throughout the area, and whether these declines correspond to a decrease in direct precipitation of phytoplankton during and after the ice-edge spring bloom.
B. OVERVIEW SUMMARY OF HLY0702 FIELD SAMPLING
In our shipboard sampling, we use a profiling conductivity-temperature-depth (CTD) and rosette system for collecting physical and hydrochemical samples. Water samples will be taken using 12 30-liter-Niskin bottles. Subsamples from multiple CTD/rosette casts are used for chlorophyll content, nutrients, particulate organic carbon, dissolved organic carbon, zooplankton, benthic population measurements and sediment tracers. In addition, optical equipment (PAR and UV) are lowered to 60-150 m for measurements of variable light penetration in the water column. A vertical net is then used to collect zooplankton for population measurements. Benthic van Veen grabs and a HAPS benthic corer are used to collect benthic fauna and sediment samples for population, community structure, food web, sediment chemistry and metabolism studies. A beam and/or otter trawl will be used to collect epifauna for population and stable isotope and lipid content measurements. Besides the standard ship sensors (atmospheric, seawater temperature, chlorophyll, multibeam), we will collect berrylium-7 (a natural radioisotope used for tracing particulate deposition to the sediments) in precipitation collectors mounted on the deck behind the bridge. Both bridge and helicopter operations will be used for seabird, marine mammal and sea ice surveys.
We plan to occupy approximately 118 stations as we did during HLY0601 (2006) in the northern Bering Sea, starting south of St. Lawrence Island (SLI) and extending to Bering Strait (Fig. 1).
Fig. 1. Final station grid for HLY0702 with station numbers and associated dates for occupation. Note that we remain 30 miles offshore from St. Lawrence Island (SLI) until the first week of June per an agreement with local hunters to minimize contact with marine mammal hunting. Additional stations will be added to the “red box” region SW of SLI as time permits.
Collaborative Programs for
Virginia Institute of Marine Science, University of Massachusetts Amherst, University of Maryland/Chesapeake Biological
Laboratory, US National Marine Mammals Laboratory (NMML)/National Oceanographic and Atmospheric Administration (NOAA), US Fish and Wildlife Service, Polar Research Institute of China (PRIC), Ocean University of China, Korean Polar Research
Institute (KOPRI), Alaska Department of Fish and Game, University of Alaska Fairbanks, Scripps Institution of Oceanography,
Woods Hole Oceanographic Institution, Lamont-Daugherty Earth Observatory, University of Colorado, local participants from Gambell and Savoonga, St. Lawrence Island, Alaska
Presentations to Schools from Ship
HLY0702 "Live from IPY" webinars from the Healy.
May 18, 2007
Webinar audio file
May 29, 2007
Webinar audio file
June 12, 2007
Webinar audio file
MODIS satellite movie (shows surface chlorophyll distributions during cruise)
Photos provided by Karen Frey and Rebecca Pirtle-Levy
This page last
updated by Kim Harmo and Lee Cooper,
Tuesday October 16, 2007
Any questions please contact us.