Organic carbon and textural characteristics of sediments within the Carretas-Pereyra coastal lagoons system, Chiapas

Abstract

In this study were analyzed the seasonal and spatial distribution of surficial sediments and their organic carbon (OC) content from Carretas-Pereyra coastal lagoon between 1997 to 2003 period. Total organic carbon determination was based on method of Gaudette et al. (1974) and sediment composition was measured by pipette analysis (Folk, 1974). There was differences between dry and wet seasons of OC in the sediments. No differences between dry and wet seasons of OC in the sediments were detected. The content of OC in the sediments. The spatial distribution of OC through the lagoons showed that the highest percentages were in stations E1 (Buenavista), E3 and E4 (Carretas) while station 1 (in the Mouth with marine influence) were lesser. Sediment texture distribution was heterogeneous between years, seasons and stations in the lagoons; station 6 was the only one conformed basically by sands. Were identified 3 zones accord their granulometry. Clays were increased inward of lagunar system (with exception E9) and the OC content decrease toward the sea. One important component was the dead leaves into the heavy fraction in February (1998) and September (2001). The tropical storm Javier (September, 1998) has like consequences a decrease in sand proportion, increase in clays and diminish of OC in almost all lagunar system. The deep in the Mouth area was reduced in half practically. Remain manifested of dredge influence made since 1999.