Revista de biología marina y oceanografía
On-line version ISSN 0718-1957
QUIJANO-SCHEGGIA, Sonia et al. First report of Pseudo-nitzschia brasiliana and P. micropora (Bacillariophycea) found in Cuyutlan Lagoon, Mexico. Rev. biol. mar. oceanogr. [online]. 2011, vol.46, n.2, pp. 189-197. ISSN 0718-1957. http://dx.doi.org/10.4067/S0718-19572011000200008.
The dominant communities of phytoplankton species present during a bloom event in Cuyutlan Lag oon, Mexico, were identified and subsequently described. Sampling was carried out in early December 2009 at eight stations. Variations in the lagoon's salinity and temperature were observed and probably corresponded to tidal exchanges. Maximum values of temperature and salinity were measured at internal stations. Due to evaporation, salinity is higher than in the ocean, and values similar to those of the ocean were determined at stations near the Tepalcates channel. Dissolved oxygen values were directly related to the depth and hydrodynamics of the sampled waters. Close to the Tepalcates channel there is a high exchange of lagoon-ocean water, and those further away have little exchange. This exchange allows for a greater sediment material resuspension (with high organic matter), due to this, this study found higher concentrations of inorganic dissolved nutrients occurring in shallower areas, influenced by the hydrodynamics of sediment release and the major retention times at internal stations (in order of 2 days), while lower concentrations were measured in proximity to the Tepalcates Channel. Bio-physical interactions determine the taxonomic composition of the main phytoplankton groups in the study area. These phytoplankton groups are dominated by diatoms primarily of the genus Pseudo-nitzschia, followed by nanoflagellates. Three Pseudo-nitzschia species were identified, P. delicatissima, which is potentially toxic, P. brasiliana and P. micropora, which are recorded for the first time on the Mexican Pacific coast.
Keywords : Phytoplankton; diatoms; coastal lagoon; physicochemical parameters.