Antarctic marine phytoplanktonic community: spatial distribution patterns and statistical assessment of the major environmental parameters associated

GARIBOTTI, I.A.; FERRARIO, M.E.; VERNET, M.

Mar del Plata, Argentina

Simposio; Joint Assemblies of the International Association for Physical Sciences of the Oceans and International Association for Biological Oceanography; 2001

International Association for Biological Oceanography

Phytoplankton community plays a crucial role in oceanic systems affecting the structure and efficiency of the food web, the recycling of nutrients and the biogeochemical cycles. Its structure (composition, cells abundance and biomass concentration) is mainly determined by physical, chemical and biological environmental processes. We analyzed the phytoplankton spatial distribution patterns and their relationship with the local environmental condition from field data recorded during a summer cruise off the west coast of the Antarctic Peninsula. Multivariate and multiple regression analyses were used to relate phytoplankton to environmental data of the area. In the study area, the most important variation of the phytoplankton abundance and biomass was found along an on/off shore gradient. Also, the biomass distribution pattern with depth changed along this gradient, with deeper biomass maximums found toward open ocean. This across-shelf distribution pattern of the phytoplankton was closely related with physical environmental conditions, and water column vertical stability was the major parameter that affected phytoplankton development. In addition, biological environmental factors, such as selective zooplankton herbivory and possibly the water seeding with eponic algae, had higher importance controlling phytoplankton structure at a meso- and small- spatial scale. These two factors apparently had a key role favoring the bloom of different microalgae classes.