Open AccessLong term picoplankton dynamics in a warm-monomictic, tropical high altitude lake
Author(s) -
Miroslav Macek,
Javier Alcocer,
Alfonso Lugo Vázquez,
María Elena Martínez-Pérez,
Laura Peralta Soriano,
Gloria Vilaclara
Publication year - 2009
Publication title -
journal of limnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.465
H-Index - 44
eISSN - 1723-8633
pISSN - 1129-5767
DOI - 10.4081/jlimnol.2009.183
Subject(s) - hypolimnion , picoplankton , thermocline , epilimnion , stratification (seeds) , chlorophyll a , environmental science , dry season , water column , plankton , biology , oceanography , ecology , phytoplankton , geology , botany , nutrient , eutrophication , seed dormancy , germination , dormancy
Long term analyses of the microbial loop, centred on the picoplankton dynamics, were carried out over a five-year (1998 to 2002) period in Lake Alchichica (Puebla, Mexico), a high altitude tropical athalassohaline lake. The hydrodynamics of the lake followed a warm-monomictic pattern with mixing at a minimum temperature during the early dry season while the stratification was pronounced in the late dry season and throughout the rainy season; anoxic conditions in the hypolimnion lasted <9 months. The annual mean concentrations of chlorophyll-a were below 4 μg L-1 in 1998, 1999 and 2001, however, 6.1 and 5.2 μg L-1 in 2000 and 2002, respectively. Total picoplankton, TPP, displayed a temporal pattern that followed the mixing-stratification cycle. The highest TPP values (the whole water column ≥5×106 cells mL-1) were found during mixing and early stratification (January-March). The minimum numbers were present during late stratification (October-November). The maximum TPP numbers were observed within the layer 0-20 m, which corresponded to the epilimnion during the stratification period. Neither the thermocline nor the deep chlorophyll maximum showed an elevated TPP concentration. In the hypolimnion, TPP numbers were low (frequently <1×106 cells mL-1) apparently as a result of the long period of anoxia. Notwithstanding autotrophic picoplankton (APP) contributed even ≥30% of TPP (2001 to 2002); no significant correlation was found between TPP and chlorophyll-a