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This study explores the factors that regulate zooplankton production in the Southeastern Bering Sea, focusing on temperature and food limitation. The research investigates the impact of temperature and species composition on growth rates, and examines the influence of predation mortality and different ecological conditions. Spatially-explicit rates and simulations/models are utilized to understand the interaction between control mechanisms.
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Who or What is Regulating Zooplankton Production in the Southeastern Bering Sea? Jeffrey M. Napp1, George L. Hunt2, Jr., Sue E. Moore1, and Christine T. Baier1 1NOAA – Fisheries, Alaska Fisheries Science Center 2School of Fisheries and Aquatic Sciences, Univ. Washington Funded Provided By: North Pacific Research Board National Science Foundation NOAA’s North Pacific Climate Regimes and Ecological Productivity
1.2 1.0 0.8 0.6 0.4 0.2 0.0 -5 5 15 25 35 Temperature Limitation • Huntley & Lopez (1992) • R2 = 0.91 • Hirst & Lampitt (1998) • Broadcast • T & BW; R2 = 0.49 • Sac • T only; R2 = 0.52 Growth Rate (d-1) Temperature (ºC)
Bering Sea Temperature Limitation 3.8 °C 3.4 °C 0.3 °C Coyle and Pinchuk (2002)
Temperature Limitation Calanus marshallae Baier and Napp (2003)
P. Stabeno, NOAA - PMEL Temperature Limitation
Food Limitation: Calanus finmarchicus St. Paul Island WindData Georges Bank Campbell et al. (2001) P. Stabeno, NOAA - PMEL
Control From Above – Does It Occur? Baleen Whales Seabirds Fish Gelatinous Zooplankton Other Crustacean Zooplankton Mesozooplankton
Kevin Raskoff Control from Above
Conclusions • Both control mechanisms are operative; how do they interact? • Need growth rate measurements at low temperatures. • Species composition affects the result. • Spatially-explicit rates, especially predation mortality. • Simulations/models important to examine different mechanisms under different conditions.