Abstract

Phytoplankton primary production (PP) was determined in a broad sector of the Térraba-Sierpe National Wetland, Costa Rica, from September to November 2008 in the rainy season and from January to March 2009 in the dry season. Six sampling stations were located at the Northern and Central zone of the wetland, according to the main expected flux of Río Grande de Térraba. Additionally other environmental parameters such as Secchi disk depth, suspended solid matter concentration, chlorophyll-a concentration, salinity, temperature, dissolved oxygen concentration, dissolved inorganic nutrients concentrations (phosphate, nitrate, ammonium and silicate), specific conductivity were also measured and a principal components analysis was performed. The PP in the Terraba-Sierpe National Wetland (HNTS by its Spanish name) was generally low, with a maximum value of 8.16gC/m²·d of Net Primary Productivity (NPP), which was recorded in the dry season, in March 2009, at Loros island. Sites that had a greater riverine influence showed lower PP values, while sites with greater marine influence presented higher PP values. These latter had an average and standard deviation of 0.79±0.50gC/m²·d (n=12). This difference is the result of the high input of freshwater and suspended solids from the Río Grande de Térraba which limits the development of marine phytoplankton in the wetland. Rev. Biol. Trop. 63 (Suppl. 1): 9-28. Epub 2015 April 01.

Key words: Primary productivity; mangroves; phytoplankton; Térraba-Sierpe; Costa Rica