Variación estacional y nictímera en la distribución del zooplancton dominante en una laguna costera tropical

Abstract

The dominant zooplankton of the La Mancha lagoon, Veracruz, Mexico, was analyzed with the objective of evaluating its seasonal and diel variability, as well as the influence of the main environmental variables on this variability. From May 2012 to April 2013, every month a 24-h cycle was completed, taking samples every 4 h, at the mouth of the lagoon. Simultaneously with zooplankton sampling, in situ environmental parameters such as temperature, dissolved oxygen, salinity, chlorophyll a and number of phytoplankton cells were recorded. We collected 54 taxa (mainly holoplankton) and 10 of them were considered dominant (total abundance > 0.5%). The zooplankton community was dominated mainly by two species of copepods (Acartia tonsa and Pseudodiaptomus pelagicus), as well as zoea larvae of brachyura (~85%). At seasonal level, the total abundance of zooplankton showed significant pulses throughout the year, one in February-March dominated by copepods and another in September-October, dominated by decapod larvae. On a diel scale, although total zooplankton abundance was significantly higher at night, only P. pelagicus, amphipods, megalopae, and other decapod larvae showed significant differences at this level. According to a Canonical Correspondence Analysis, the mouth stage (open/close), the number of cyanophytes and precipitation were the most important environmental factors in determining the abundance of the dominant zooplankton.

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“…Grande, en contraste, durante la temporada seca, entre los meses de noviembre a mayo, registra un promedio de precipitación mensual menor a 60 mm, presentando condiciones marinas (Mecalco-Hernández et al, 2018). Durante el periodo de estudio, la boca de comunicación con el mar permaneció cerrada de mayo a junio 2012 y de enero a marzo 2013, con una amplitud media anual de marea de 26.11 cm.…”