Variación diurna de la materia orgánica particulada en una laguna costera del Golfo de California

Three diel cycles of sampling were carried out in February, May, and October 1991 at the mouth of Bahía Concepción. This was done to describe the diurnal variability of size-fractionated phytoplankton abundance, species composition, pigments, and particulate organic matter (POM) in two depths. These variables show a very marked monthly variation, with February being the richest period in organic particles. Comparing the results obtained in the three cycles, we can observe that no significant differences (p=0.05%) exist for both sampling levels during February and May. However, temperature, abundance, and species composition show significant differences (p=0.05%) between sampling levels during October. On the other hand, our results show a correlation between the import and export of organic matter particles during the tide phases. The analysis of variance shows significant differences (95% confidence) in the POM concentrations in the February and October months. In February, the highest concentrations were recorded during the high tide. In October, an inverse condition was observed. The results of these cycles display the influence of the Gulf of California waters flowing into Bahía Concepción in February bringing in particulate organic matter. During October, an outflow of particles from the bay to the ocean was observed. In May an intermedian condition was observed.