HR: 1340h
AN: GC13A-0933    [Abstracts]
TI: Interannual Variability of Primary Production and Fishery in Response to Climate Changes in the Bering Sea
AU: * Jin, M
EM: mjin@iarc.uaf.edu
AF: International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Dr., Fairbanks, AK 99775-7340, United States
AU: Deal, C
EM: deal@iarc.uaf.edu
AF: International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Dr., Fairbanks, AK 99775-7340, United States
AU: McRoy, P
EM: ffcpm@uaf.edu
AF: International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Dr., Fairbanks, AK 99775-7340, United States
AB: The climate trends of reducing sea ice cover and rising temperature have profound impacts on the lower tropic level production and fishery production. The lower trophic level production from 1970 to 2005 was simulated using a vertically 1-D coupled ice-ocean ecosystem model (Jin et al., 2007) that includes 10 compartments: three phytoplankton (pelagic diatom, flagellates and ice algae), three zooplankton (copepods, large zooplankton, and microzooplankton), three nutrients (nitrate+nitrite, ammonium, silicon) and detritus. By using a turbulence closure model (Mellor, 2001), tidal mixing and its interactions with wind stirring, and thermal stratification were realistically reproduced. The 1-D model was applied to the mooring site M2 in the southeastern Bering Sea. The water depth H=74m. The model is forced by NCEP reanalysis data and sea ice concentration data from Hadley Center (monthly) before 1978 and SSM/I (daily) after 1997. Surface boundary includes wind stress, heat and salt flux. Model results are validated favorably with observations: 1) temperature, salinity, fluorometer data at 12m, 24m and 44m at NOAA/PMEL mooring from 1995-2005; 2) daily SeaWiFS chl a data (1997-2005). While the quantity of variability of the primary production did not show an increase/decrease trend in the past three decade, there exists a shift of dominant phytoplankton species coincident of the Pacific Decadal Oscillation (PDO) index. The model primary production were dominant by ice algae before the 1976/77 regime shift, and by open water species of diatom and flagellates thereafter with only occasional ice algal blooms. Fish catches in the eastern Bering Sea showed mixed reponse to the climate changes. Among the 12 dominant economic fish species, only Walleye pollock and Yellowfin sole showed significant correlations with the PDO index in certain regions.
UR: http://people.iarc.uaf.edu/~mbj/
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0466 Modeling
DE: 0750 Sea ice (4540)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 4273 Physical and biogeochemical interactions
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting