Spatial Heterogeneity of Phytoplankton In an Estuary of Cantabria, Northern Spain

Abstract

Phytoplankton distribution and structure in the estuary of Cantabria, Northern coast of Spain, Bay of Biscay, was studied. Samples were taken monthly at three stations situated between the upper reaches or the tide (st-3) and the mouth of the estuary (st-1), and included near - shore and middle points. The stations are characterized as: Station 1 (st-1) - the most saline, with a low concentration of nutrients, high temperatures; Station 2 (st-2) - less saline but has elevated contents in nutrients, low temperature; and Station 3 (st-3) - the least saline but with higher nutrient content, low temperature. The phytoplankton communities did not vary among stations (they were euryhaline species in most cases). However, the response of the community to the different environments varied as follows: Station 1- elevated productivity and low biomass; Station 2- elevated productivity, low diversity and biomass ; and Station 3 - low productivity and diversity and the highest biomass.