A phytoplankton-zooplankton model of the middle and outer shelf domains of the Southeast Bering Sea Shelf during spring bloom conditions

• Other Authors: Magley, Wayne Carl., Florida State University
• Format: Text
• Language: English
• Subjects: Biology; Oceanography; Bering Sea
• Online Access: http://purl.flvc.org/fsu/lib/digcoll/etd/3162051; http://fsu.digital.flvc.org/islandora/object/fsu%3A78249/datastream/TN/view/A%20phytoplankton-zooplankton%20model%20of%20the%20middle%20and%20outer%20shelf%20domains%20of%20the%20Southeast%20Bering%20Sea%20Shelf%20during%20spring%20bloom%20conditions.jpg

As part of the Processes and Resources of the Bering Sea Shelf (PROBES) program, a vertical time dependent phytoplankton-zooplankton model was developed for application to the middle and outer shelf domains of the Southeast Bering Sea Shelf. The model included two phytoplankton groups and four zooplankton groups. Use of two phytoplankton groups allowed the inclusion of phytoplankton with different uptake rates, nutrient requirements, sinking rates, and grazing pressures. All four zooplankton groups grazed phytoplankton and one group could also graze detritus or smaller zooplankton. Two zooplankton groups could produce eggs that developed through naupliar and copepodite stages during the simulation period. In response to low rations, zooplankton were able to vertically migrate in the water column. Simulations of the middle and outer domains for an eighty day period were completed for 1980 and 1981 and compared to PROBES field observations. The model successfully simulated the spring algal bloom and the growth and reproduction of multiple zooplankton groups. The model demonstrated that zooplankton species on the middle shelf had little impact on the phytoplankton species composition. Approximately sixty-five percent of the nitrate nitrogen loss over the water column on the middle shelf reached the benthos as algal biomass. This supported a benthic community on the middle shelf. Zooplankton grazing pressure on the outer shelf was an order of magnitude greater than on the middle shelf and led to a phytoplankton species composition shift from a diatom to a Phaeocystis poucheti community. Between thirty-nine and sixty-nine percent of the nitrate nitrogen loss over the water column went to the zooplankton compartment. This supported a pelagic community on the outer shelf dominated by walleye pollock. Model calculations of new production to total production (f ratio) indicated rapid responses to wind mixing events. The f ratios suggested that ammonium could be important in sustaining production during the summer on the middle shelf. Source: Dissertation Abstracts International, Volume: 51-04, Section: B, page: 1594. Major Professor: Richard L. Iverson. Thesis (Ph.D.)--The Florida State University, 1990.