Resumo

GONZALEZ CONTRERAS, Circe Guadalupe; ALCOCER, Javier  e  OSEGUERA, Luis Alberto. Clorofila a fitoplanctónica en el lago tropical profundo Alchichica: un registro de largo plazo (1999-2010). Hidrobiológica [online]. 2015, vol.25, n.3, pp.347-356. ISSN 0188-8897.

The temporal fluctuation of phytoplankton biomass has been well studied in temperate lakes. Opposite, tropical lakes lack equivalent studies, particularly those considering long-term monitoring. The aim of the present study is to uncover patterns in the temporal and vertical variation of the phytoplankton biomass in Lake Alchichica, Puebla, through considering twelve years (1999-2010) of vertical chlorophyll a profiles recorded on a monthly basis with a PNF-300 natural fluorescence profiler (Biospherical). We recognize a clear seasonal pattern in the chlorophyll a concentration with three maxima: a) during the winter circulation period throughout the water column, b) at the onset of the stratification, accumulated close to the surface, and c) along the well-established stratification, located at the metalimnetic deep chlorophyll maximum. This pattern is clearly related with the thermal behavior of the lake corresponding to warm-monomixis. It was observed a positive correlation with the mixed layer and a negative correlation with the euphotic zone. A time-series analysis ratified the annual cycle, however it did not identify interannual patterns or long-term trends; this is, Alchichica is regular and predictable year after year, with no relevant interannual differences along the studied period.

Palavras-chave : Chlorophyll a; long term dynamics; oligotrophic lake; PNF-300; tropical lake.

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