Benthic assemblages of a temperate estuarine system in South America: Transition from a freshwater to an estuarine zone

Relationships between the spatial distribution of oligochaetes (Annelida, Clitellata) and environmental variables in a temperate estuary system of South America (Río de la Plata, Argentina)

“…This species is frequently found in the main stretch of the Lower Paraguay and Parana´rivers Montanholi-Martins & Takeda 1999;Ezcurra de Drago et al 2004;Marchese et al 2005). In the Rı´o de la Plata, this species has been previously recorded in the sandy sediments of the upper section (Armenda´riz & Ce´sar 2001;Cortelezzi et al 2007). In this study, N. bonnetoi was registered in the southern locations (Sites Table 1. 10 and 11), those considered reference sites (because of their relatively undisturbed environments), although in low numbers.…”

“…The macroinvertebrates in the Rı´o de la Plata River have been studied by a number of authors Darrigran & Lo´pez Armengol 1998;Rodrigues Capı´tulo et al 1998Ce´sar et al 2000;Cortelezzi et al 2007), while the species composition and ecological requirements of oligochaetes in particular have been analysed during recent years in other larger rivers in South America (Montanholi-Martins & Takeda 1999;Takeda 1999;Ezcurra de Drago et al 2004;Marchese et al 2005). Furthermore, in various parts of the world, studies on the oligochaete fauna from temperate estuaries subjected to anthropogenic impact have indicated that the most significant environmental factors affecting their distribution are the salinity, turbidity, discharge, trophic condition, sediment characteristics and general quality of the bodies of water in question (Moroz 1994;Finogenova 1996;Gonza´lez-Oreja & Saiz-Salinas 1999;Seys et al 1999).…”

Benthic communities on hard substrates covered by Limnoperna fortunei Dunker (Bivalvia, Mytilidae) at an estuarine beach (Río de la Plata, Argentina)

“…Darrigran, and Rioja (1988), for example, described fauna of the Isopoda, Gullo (1995) the diversity of the Hirudinea, and Darrigran (1999) the distribution of the Mollusca in the estuary. Furthermore, only few studies on benthic communities have been conducted on the Río de la Plata Estuary after the mussel's invasion, and those reports have dealt mostly with populations on soft substrates (Rodrigues Capítulo et al 2003;Giberto et al 2004;Cortelezzi et al 2007;Ocón et al 2008).…”

“…Benthic ecological studies are difficult, scarce, and fragmented because of the extensive physical dimensions of such a system, and as a result of limited financial resource as well. Nevertheless, some studies have been carried out on the seasonal dynamics and spatial-distribution patterns of the macroinvertebrate fauna along both banks of the estuary as well as within the surf zone (Boschi 1988;Rodrigues Capítulo et al 2003;Giberto et al 2004;Venturini et al 2004;Giménez et al 2005;Cortelezzi et al 2007;Ocón et al 2008). Studies, however, on the hard littoral substrates of the benthos (i.e., especially those on the benthic epifauna) in the Río de la Plata Estuary have been notably scarce (e.g., Darrigran et al 1998).…”

Temporal dynamics of deep infralittoral macrobenthic fauna in a subtropical estuarine environment

“…Inside estuarine regions, sediment characteristics of the substrate (e.g. grain size, organic matter content) and in particular salinity of the water column have long been reported as the main abiotic variables which can determine the spatial-temporal patterns of distribution on macrobenthic assemblages (Holland et al, 1987;Warwick et al, 1991;Schlacher & Wooldridge, 1996;Mannino & Montagna, 1997;Giménez et al, 2005;Cortelezzi et al, 2007).…”