Open AccessEcological indicators of the phytoplankton community structure in Bahía Concepción, Gulf of California, Mexico.
Author(s) -
Gerardo Verdugo Díaz,
Abraham Sánchez López,
Ismael Gárate Lizárraga
Publication year - 2010
Publication title -
cicimar oceánides
Language(s) - English
Resource type - Journals
eISSN - 2448-9123
pISSN - 1870-0713
DOI - 10.37543/oceanides.v25i2.85
Subject(s) - phytoplankton , abundance (ecology) , chaetoceros , species richness , water column , biology , ecology , oceanography , taxon , community structure , nitzschia , nutrient , geology
Seasonal changes in the spatial distribution of the phytoplankton community were determined inBahía Concepción, B.C.S., from 1991 to 1993. The total abundance and the seasonal variations of phytoplankton size fractions (nanno and microphytoplankton) as well as its structure were determined. A total of 235 taxa were identified. Diatoms were the best represented group due to their high species richness (131). The most important genera were Chaetoceros, Rhizosolenia and Nitzschia. The second important group were dinoflagellates (92 species), represented mainly by Protoperidinium, Ceratium and Prorocentrum. The third numerically important group were the silicoflagellates (9 species). The most representative genus of this group was Dictyocha. A major presence of the diatoms was observed during the cold months with a homogeneous water-column. Major presence of dinoflagellates was recorded during the warm season when the water-column appeared stratified. Ten species of dinoflagellates were considered as toxic or potentially toxic. Total phytoplankton abundance did not show a clear seasonal pattern; nevertheless, the interannual variations exhibited an important decline ofabout 25 % during 1992 and 1993. These changes were related to positive anomalies of temperature. Altough phytoplankton abundance diminished, the percentage contribution of nannophytoplankton was stable.