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Mantelatto F.L.,University of Sao Paulo | Cuesta J.A.,Institute Ciencias Marinas Of Andalucia
Helgoland Marine Research | Year: 2010

The first zoeal stage of the endemic southern Atlantic pinnotherid crab Austinixa aidae is described and illustrated based on laboratory-hatched material from ovigerous females collected from the upper burrows of the thalassinidean shrimp Callichirus major at Ubatuba, São Paulo, Brazil. The zoeae of Austinixa species can be distinguished from other pinnotherids and especially from zoeae of the closely related species of Pinnixa by the telson structure. © 2010 Springer-Verlag and AWI.

Reuschel S.,University of Regensburg | Cuesta J.A.,Institute Ciencias Marinas Of Andalucia | Schubart C.D.,University of Regensburg
Molecular Phylogenetics and Evolution | Year: 2010

A phylogeographic analysis is carried out for the widely distributed European littoral prawn Palaemon elegans in order to test for potential genetic differentiation and geographic structure. Mitochondrial sequences were obtained from 283 specimens from the northeastern Atlantic, the Baltic, Mediterranean, Black and Caspian Seas. Our study revealed a surprisingly complex population structure. Three main haplogroups can be separated: one from the Atlantic (Type I) and two from the Mediterranean (Types II and III). While the Mediterranean types occur in sympatry, a clear phylogeographic break was observed along the Almería-Oran Front separating Type I and giving evidence for a genetic isolation of Atlantic and Mediterranean populations. Type III represents the most distinct haplogroup with high levels of nucleotide divergence, indicating the occurrence of a cryptic species with a Messinian origin. The colonization of the southeastern Baltic Sea is most likely due to human introduction. © 2010.

Diez-Minguito M.,University of Granada | Baquerizo A.,University of Granada | Ortega-Sanchez M.,University of Granada | Navarro G.,Institute Ciencias Marinas Of Andalucia | Losada M.A.,University of Granada
Journal of Geophysical Research: Oceans | Year: 2012

This study analyzes tide transformation in the Guadalquivir estuary (SW Spain). When fresh water discharges are less than 40 m3/s, the estuary is tidally-dominated (flood-dominated) and well mixed. Under such conditions, the estuary can be divided into three stretches, each characterized by a different tide propagation process. In the first stretch of 25 km, the dominant process is diffusion. In the next stretch, approximately over 35 km length, convergence and friction processes are in balance. At the head of the estuary, in the last stretch, the tidal motion is partially standing because of tidal reflection on the Alcal del Río dam, located 110 km upstream from the estuary mouth. The reflection coefficient R varies with the frequency; for diurnal constituents its magnitude RD is 0.25; this value increases in the case of semi-diurnal (RS0.40), and quarter-diurnal constituents (RQ0.65), and reaches its minimum at the sixth-diurnal components (RX0.10). The tidal reflection can generate residual currents that have consequences in the bed morphology. Furthermore, when the fresh water discharges are greater than 400 m3/s, the estuary is fluvially-dominated and the water level can be calculated as the linear superposition of tide and river contributions. However, superposition arguments do not hold for currents at any point in the estuary. Copyright 2012 by the American Geophysical Union.

Subida M.D.,Institute Ciencias Marinas Of Andalucia | Berihuete A.,University of Cadiz | Drake P.,Institute Ciencias Marinas Of Andalucia | Blasco J.,Institute Ciencias Marinas Of Andalucia
Science of the Total Environment | Year: 2013

A 4-year annual sediment survey was conducted in an organically enriched tidal channel to compare the performance of univariate community descriptors, traditional multivariate techniques (TM) and artificial neural networks (AANs), in the assessment of infaunal responses to moderate levels of sediment metal contamination. Both TM approaches and the SOM ANN revealed spatiotemporal patterns of environmental and biological variables, suggesting a causal relationship between them and further highlighting subsets of taxa and sediment variables as potential main drivers of those patterns. Namely, high values of non-natural metals and organic content prompted high abundances of opportunists, while high values of natural metals yielded typical tolerant assemblages of organically enriched areas. The two approaches yielded identical final results but ANNs showed the following advantages over TM: ability to generalise results, powerful visualization tools and the ability to account simultaneously for sediment and faunal variables in the same analysis. Therefore, the SOM ANN, combined with the K-means clustering algorithm, is suggested as a promising tool for the assessment of the ecological quality of estuarine infaunal communities, although further work is needed to ensure the accuracy of the method. © 2013 Elsevier B.V.

Gonzalez-Ortegon E.,Bangor University | Gonzalez-Ortegon E.,Institute Ciencias Marinas Of Andalucia | Pascual E.,Institute Ciencias Marinas Of Andalucia | Drake P.,Institute Ciencias Marinas Of Andalucia
Journal of Experimental Marine Biology and Ecology | Year: 2013

The respiratory response of six caridean shrimp species under different salinity and dissolved oxygen concentrations (DO) has been carried out at 20 and 25°C. The lowest mean specific oxygen consumption rates (MO2) were found for the less active benthic crangonids Crangon crangon and Philocheras monacanthus; whereas the highest ones corresponded to the two more mobile native palaemonids Palaemon longirostris and Palaemonetes varians. The level of oxygen regulation displayed by the different native species was mainly related with environmental characteristics of their common habitats: species with temporal (C. crangon) or permanent (P. varians) estuarine habitats tended to be more tolerant of salinity changes and/or hypoxia, than are fully marine (P. monacanthus) or freshwater (Atyaephyra desmarestii) species. The estuarine P. longirostris showed moderate oxygen independence, but rather independent of salinity and temperature fluctuations. The exotic shrimp P. macrodactylus seemed to have higher tolerance to hypoxia that its native counterpart P. longirostris at brackish waters, but only under moderate temperature (at 20°C). Results of this study suggest that a simultaneous evaluation of respiration rates and their dependence on DO could be an integrative way of determining the potential effects of increased salinity, temperature and hypoxia on aquatic species with different mobility and/or from different habitats. © 2013 Elsevier B.V.

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