%0 Journal Article
%T Benthic Macrofauna Associated with Submerged Bottoms of a Tectonic Estuary in Tropical Eastern Pacific
%A Carlos E. Guevara-Fletcher
%A Jaime R. Cantera Kintz
%A Luz M. Mej¨ªa-Ladino
%A Fabi¨¢n A. Cort¨¦s
%J Journal of Marine Biology
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/193759
%X The composition and distribution of the main associations of submerged macrobenthos of Bah¨ªa M¨¢laga (Colombian pacific coast), were studied in relation to the distribution of hard and soft substrates and some abiotic factors. Eight localities were sampled during six months: three in the external border of the estuary and five in the inner part. In total, 728 organisms were registered, belonging to 207 species, 132 genera, 86 families, and 14 orders of six invertebrate groups (Porifera, Cnidaria, Polychaeta, Mollusca, Crustacea, and Echinodermata). The submerged bottoms presented soft and hard substrates, with rocks and thick sand in five sites, soft bottoms with fine sand in one, and soft bottoms with slime and clay in two. The temperature and salinity values were higher in the external localities, while dissolved oxygen and pH were higher in the internal localities. The localities with hard substrates presented the highest richness of species while the soft substrates, were characterized by a paucity of species and individuals. The similarity classification analyses showed two groups: one characterized by having 61 species in common and high richness with 113 exclusive species. The other group with low diversity and richness values, 37 species in common and 23 exclusive species. 1. Introduction Four main estuarine types are recognized: drowned river valleys (coastal plain estuaries), lagoons (sand bar or barrier island estuaries), fjords (glaciers originated estuaries), and tectonic estuaries [1, 2]. The latter is caused by tectonic processes such as faulting, gravels formation, landslide, volcanic eruption, and marine erosion. Drowned river valleys and lagoons are characterized by soft substrates, mud or sand bottoms, while tectonic estuaries present higher diversity of substrates, including rocky shores, and cliffs, and consequently more coastal ecosystems. These ecosystems are comprised of a high variety of habitats with different types of substrate, bottom topography and sediment types, presence of vegetation cover and biogenic structures, resulting from erosion processes, river fluxes, and mangrove leaves decomposition. As a result of the habitat diversity and its interaction with the environment, benthic (epi- and endobenthic) communities differ in taxonomic composition, specific abundance and functional role of organisms [3, 4]. Knowledge of the abundance patterns and taxonomic composition of the benthic communities and their trophic relationships is important to reveal their functional role [5]. The main factors that influence the composition
%U http://www.hindawi.com/journals/jmb/2011/193759/