Short and medium-term changes of Pseudodiaptomidae copepods in the Amazonian Mangrove Coast: The Paracauari River estuary (Brazil)

Given the importance of copepods in pelagic food webs, short- and medium-scale temporal variation in the distribution and abundance of copepods of the genus Pseudodiaptomus was investigated in an oligo-mesohaline estuary in northern Brazil. This system is characterized by high local hydrodynamics and nutrient input from the Paracauari River and Marajo Bay, and marked seasonal variation in rainfall levels. The temporal variation in the abundance of copepods was analyzed in the context of some hydrological variables -- tide height, salinity, temperature, pH, and concentrations of suspended particulate material, dissolved oxygen and chlorophyll a. The results indicate that variation in composition and density of the Pseudodiaptomidae copepods in the Paracauari estuary is determined by the interactive effect of the freshwater influx from Marajo Bay, tides, and the rainfall regimen, which modulate local salinity. The absence of diurnal variation in species composition and density was determined by the high local hydrodynamics, which provoke the constant mixing of the estuary's water.