Natural and human effects in coastal systems can favor important changes in phytoplankton communities. Contributions of macronutrients (nitrogen and phosphorous) and their role in the blooming of harmful species are already known, which is why we can foresee that the frequency of these events might favor important consequences in environmental health.

Gymnodinium catenatum is a dinoflagellata responsible for the majority of the harmful events in the Mexican Pacific. Its current record locates them from Ensenada down to Oaxaca and Chaipas. There are historical recurrent records in the area of (BAMAZ) during the months of March-April and November.

The Bay of La Paz (BAPAZ) also has records of this species, but its abundance is comparatively smaller. An analysis of the chemical conditions of both areas clearly shows larger concentrations of nitrogen and phosphorous in BAMAZ, which suggests that this species has high rates of affinity toward these nutrients.

In this proposal we expect to study the effects of different concentrations of nitrogen and phosphorous and their N:P relationship in growth and toxicity of isolated strains in both areas, and prove our hypothesis.