La comunidad macrobentónica del estuario del Guadalquivir
The intertidal macrobenthic community of the Guadalquivir estuary (last 50 km) was studied between May 1997 and April 1999 at five sampling sites located to 50, 40, 32, 20 and 8 km from the river mouth. Five monthly replicates were taken at each sampling site by means of an Ekman-Birge grab (15 ˟ 15...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2001 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/318882 |
| Acceso en línea: | http://hdl.handle.net/10261/318882 |
| Access Level: | acceso abierto |
| Palabra clave: | Medio Marino Macrobentos Estuario del Guadalquivir gradiente salino Golfo de Cádiz |
| Sumario: | The intertidal macrobenthic community of the Guadalquivir estuary (last 50 km) was studied between May 1997 and April 1999 at five sampling sites located to 50, 40, 32, 20 and 8 km from the river mouth. Five monthly replicates were taken at each sampling site by means of an Ekman-Birge grab (15 ˟ 15 cm). A total of 24 taxa were collected but the specific richness increased from the inner (12) to the outer estuary (22). Only four taxa (Oligochaeta; Nereis diversicolor Müller, 1776; Streblospio shrubsolii (Buchanan, 1890) and Corophium orientale Schellenberg, 1928) were considered as constant (present in more than 75 % of the months) for at least one sampling site, while ten were rare (present in less than 12 % of the months) through the estuary. There was a clear dominance of a small number of species, although the dominant taxa changed from one site to another: Oligochaeta at the two inner sites; the amphipod C. orientale at the intermediate site; the polychaetes N. diversicolor and S. shrubsolii at the two outer sites.On average, the macrobenthic density was higher at the most marine site (5 409 indiv ⋅ m-2; 9 118 mg AFDW ⋅ m-2), where numerical abundance showed noticeable seasonal pattern (minimum values in summer and maximum in autumn/winter). In the rest of the estuary, although the community density oscillated over time, a clear seasonal trend was not observed. The spatial and temporal density of dominant taxa seemed to maintain a strong relation with the salinity gradient. The latter showed considerable differences between the first (wet) year and the second (dry) year.As a consequence of the accident occurred in the Aználcollar mine in April 1998, a considerable volume of untreated acid fresh water, with a high content in metals, was released into the estuary. According to the Bray-Curtis similarity index between samples, there were no significant differences in the benthic community of the estuary between the first (before the spill) year and the second (after the spill) year (two-way nested ANOSIM tests; p 0.05 for abundance and biomass data). However, differences were significant (p 0.01) between sampling sites. |
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