Vertical Distribution of Radiolarians and Their Role in Epipelagic Communities of the East Pacific Rise and the Gulf of California

Vertical distribution of different groups of radiolarians and mesozooplankton (l = 0.2–3.0 mm) and the contribution of radiolarians to total biomass of bathometer-sampled zooplankton were studied in the epipelagic East Pacific Rise and the Gulf of California during 49th cruise of R/V “Akademik Mstislav Keldysh” (September–October, 2003). The production of the symbiotic algae of acantharians and colonial radiolarians as well as their contribution to the total primary production were evaluated. The proportion of all radiolarian groups in the total zooplankton biomass was shown to range from 1.4 to 11.5%. The contribution of zooxanthellae to the total primary production was not great in the studied region and equaled 0.1–1.2 and 0.3–0.7% for colonial radiolarians and acantharians, respectively.__________Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 3, 2005, pp. 339–348.Original Russian Text Copyright © 2005 by Zasko, Rusanov.