Phytoplankton-zooplankton interactions : data analysis and modelling (with particular reference to Ocean Station P (50⁰N, 145⁰W) and controlled ecosystem experiments) ...

• Main Author: Parslow, John Stanley
• Format: Text
• Language: English
• Published: University of British Columbia 2010
• Subjects: Subarctic
• Online Access: https://dx.doi.org/10.14288/1.0080145; https://doi.library.ubc.ca/10.14288/1.0080145

The anomalous phytoplankton seasonal cycle in the Subarctic Pacific has been attributed to grazing control. In simple classical models of the phytoplankton-zooplankton interaction, grazing thresholds are found to be necessary to obtain this type of control. Weathership observations at O.S.P. are analysed to provide a basis for a more realistic model. Phytoplankton are present at O.S.P. in almost uniformly low concentrations (about 0.4 mg Chla.m⁻³), have low photosynthetic efficiency (<0.5 mg C.mg Chia⁻¹.ly⁻¹), adapt to seasonal changes in solar radiation and show most surface inhibition in the spring. A numerical production model based on these results and driven by physical time series from the weatherships yields low annual production levels compared with previous estimates. Predicted production levels are sensitive to the choice of respiration rate, and introduction of a rapid light response or 'Marra' effect results in a doubling of net production. Predicted year to year variation is low and might be ...