Texture and organic matter content of surface sediments from Metztitlan Lake, Mexico

Background: Texture and organic matter content of the surface sediments of aquatic ecosystems provide important information about the nature of the sedimentary processes that occur there also to exerting a notable influence on the supply of nutrients in the water column and on the composition and distribution of benthic biota. Goals: Due to the lack of antecedents, in this study an evaluation of the textural characteristics and organic matter content of the surface sediments of Lake Metztitlan was carried out. Methods: Sediment samples (n= 35) were collected in the dry and rainy season for 2 years. The granulometric analysis was carried out using sieving and pipetting techniques. The content of organic matter (OM) was determined by the ignition technique at 550 degrees C. Results: The textural analysis of sediments allowed to recognize a wide predominance of silty clay in the most of the lake bottom, in addition to two smaller groups: clayey silt, along the front of the mouth of the lake's main tributary, and clays, in the areas of lower hydrodynamic. Furthermore, the proportion of organic matter in the sedimenst ranged between 7 and 12%. The data obtained did not show significant differences between the seasons of the year analyzed. Conclusions: The predominance of fine sediments with content of organic matter, probably have a major role in the trophic structure of the lake being the detritus an important path to the energy flow in the ecosystem.