Seston dynamics in a saline Mexican lake

摘要

Organic and inorganic matter in aquatic ecosystems may occur in both dissolved and particulate form. Seston is the paniculate matter present in the water column that is composed of 2 fractions: organic and inorganic matter (Marga-lef 1983, Wetzel 1983). Inorganic matter could be litho-genic (clay and silt), biogenic (silica), and/or originated by chemical precipitation (carbonates) (Effler et al. 2002, Peng & Effler 2005). The study of seston mass and composition is important to understanding the dynamics of the organic and mineral matter (Punning et al. 2003).rnPrevious studies from a wide diversity of geographic regions covering temperate and tropical zones report organic matter as the most abundant fraction of seston, predominantly particulate organic carbon that exhibits seasonal dynamics similar to those of chlorophyll a (Callieri 1997, Jarvinen et al. 1999, Brzakova et al. 2003, Punning et al. 2003); however, the seston of some lakes, such as Lake Mag-giore, could be dominated by the inorganic fraction during certain periods (Callieri 1997).rnAlthough previous studies on warm, monomictic Lake Alchichica relate to dynamic aspects such its hydrodynamics (Alcocer et al. 2000), nutrient concentration (Sanchez Silva 2006), and phytoplankton biomass (Sanchez Reyes 2001), the dynamics of the seston concentration, distribution, and composition was unknown. The purpose of this investigation was to analyze the seasonal and vertical variation of seston in Lake Alchichica to better understand the organic and inorganic matter dynamics in tropical, saline lakes.