Resumo

OSEGUERA, Luis A.; ALCOCER, Javier  e  VILLARREAL QUINTERO, Einye Y.. Lake metabolism of a deep, tropical lake: Carbon source or sink?. Hidrobiológica [online]. 2015, vol.25, n.3, pp.391-399. ISSN 0188-8897.

The epicontinental aquatic systems are an important component in the global carbon cycle. In order to generate a baseline as whether tropical lakes act as carbon dioxide (CO2) source or sink, we evaluated the gross (GPP) and net (NPP) primary production and respiration (R) in the euphotic zone of a deep, oligotrophic, tropical lake. GPP fluctuated between 1,809 and 4,195 mg C m-2 d-1; three peaks were observed throughout the year. These peaks are associated to the three main phytoplankton events of Lake Alchichica: the diatom bloom during the mixing period, the cyanobacteria bloom at the onset of the stratification period and the deep chlorophyll maximum along the stratification. R varied between 87 and 5,966 mg C m-2 d-1. Despite its oligotrophic condition, Lake Alchichica acts as a CO2 sink because it is mostly autotrophic along the year. The annual gross primary production (GPP) exceeds respiration (GPP:R = 4.39 ± 6.84 ) and therefore, the annual NPP was is positive.

Palavras-chave : Mexico; oligotrophic lake; primary production; respiration.

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