Distribution of benthic macro invertebrates in the estuarine ecosystem the Ri�to, Riohacha - Colombian Guajira

Abstract

Objective: The research was aimed to describe the distribution of benthic macro invertebrates associated with estuarine ecosystem the Riito (ER) in Riohacha, La Guajira. Methods: The benthic macro invertebrates were evaluated in three sites: The Quebrada (LQ), Villa Co familiar (VC) and the mouth (DB) during the period between December (2008) and July (2009). The physical and chemical variables that were identified were: salinity (UPS), water temperature (oC), Turbidity (cm), alkalinity (mg/l CaCO3 ), hardness (mg/l CaCO3 ), pH, OD (mgL-1) % saturation of OD (%), depth (cm), granulometry (%), organic matter (%), the air temperature (°C), precipitation (mm) and humidity. The sediment and biological samples were taken with an Ekman dredge (0.02 m2 ). Findings: The taxa Artropoda (Malacostraca, Ostracoda and Insecta), Mollusca (Bivalvia and Gasteropoda) and Annelida (Polychaeta) were the populations collected. The average was the 15.995 ind*m-2 ; the lower value was obtained in December (121 ind*m-2) and the highest in July (3,348 ind*m-2). LQ presented the highest density (4778 ind*m-2). The taxon present at all sites was Tynaponinae, the rich were gender Tubifex and platyrachis Pyrgophorus. The diversity (H’) was 0.75 1.24 on LQ; in VC and 1.63 in DB, the richness (R1) was 1.00 1.79 on LQ; in VC and 2.55 in DB and equity (E) 0.66 0.65 in DB, in VC and 0.92 in DB. Application: The distribution community structure of agencies such as the abundance, species richness, and the physical and chemical variables of the water, sediment and environmental were correlated. The variations and fluctuations of saturation of OD, Sand Media and very fine sand, silt and clay regulated communities. Keywords: Benthic Macro Invertebrates, Distribution, Estuarine Ecosystem