This award is part of the SUPER - Subarctic Pacific Ecosystem Research Program. The Principal Investigator, Landry, has moved from the University of Washington to the University of Hawaii. This is a change-of-institution action for the Principal Investigator's award. The project focuses on understanding the food web relationships and other upper ocean processes leading to the population dynamics of phytoplankton and zooplankton in the Subarctic Pacific, for comparison with the North Atlantic in which similar work had been done. Initially, work in the Subarctic Pacific centered on the larger size fractions of both phytoplankton and zooplankton and on the notion that phytoplankton growth was continuously balanced by zooplankton feeding (the Major Grazer Hypothesis). Unusual characteristics of the surface water mass allowed the maintenance of higher zooplankton abundance in the euphotic zone, thus allowing zooplankton to closely track any phytoplankton increases. The lag seen in the North Atlantic System is not seen. The results of the initial SUPER Program, indicate that zooplankton numbers/feeding capabilities are 10X too low to account for the balance of populations, and that the copepods must have a direct feeding connection to microzooplankton (heterotrophic flagellates and ciliates). The Major Grazer Hypothesis is not an accurate paradigm of the ecosystem dynamics; an alternative Limited Mixing/Micrograzer Hypothesis has been forwarded and tests of this new hypothesis are now underway. This involves comparisons of phytoplankton (all sizes) production rates with zooplankton (all sizes) grazing rates, and a quantitative assessment of nitrogen dynamics as a basis for estimates of phytoplankton production capabilities.
