Micro- and mesozooplankton communities in the surf zone of a tropical sandy beach (Equatorial Southwestern Atlantic)

Sandy beaches constitute important ecosystems from both ecological and socioeconomic standpoints. The ecosystems of tropical zones present a high diversity and are sensible to global climatic changes, as well as to local impacts. Despite its relevance, researches on biodiversity and existing ecological processes, like size distribution of plankton communities, in these regions are often neglected. Here, the first results of a study on the structure of zooplankton communities in a tropical sandy beach (Equatorial Southwestern Atlantic) is presented. Species were divided in two size classes (micro- and mesozooplantkon) in order to verify which possess higher diversity and abundance (ind m(-3)). Sampling was conducted in dry and rainy season in the course of a year, aiming to cover possible variations due to weather. Data support the hypothesis that small copepod species and developmental stages of some pelagic copepods (microzooplankton) are more abundant and diverse in the surf zone of a tropical beach in both dry and rainy season. Biological characteristics of the observed species and semiarid tropical coast environmental factors, such as high and constant temperature and oligotrophic waters, explain the diversity and abundance of microzooplankton. Results suggest that a broader view of plankton communities is necessary to understand food webs and resilience in tropical ecosystems, especially concerning smaller species and those in developmental stages.