Assemblages of the moulluscan fauna in subtidal soft bottoms of the Ría de Aldán (north-western Spain)

2006 ◽  
Vol 86 (1) ◽  
pp. 129-140 ◽  
Author(s):  
Antía Lourido ◽  
Loreto Gestoso ◽  
Jesús S. Troncoso
Keyword(s):  
Grain Size ◽  
Spatial Distribution ◽  
Multivariate Analyses ◽  
Fine Sand ◽  
Typical Species ◽  
Soft Bottoms ◽  
Western Spain ◽  
Faunal Distribution ◽  
Sandy Sediments ◽  
North Western

The composition and spatial distribution of the mollusc fauna on the subtidal soft bottoms of the Ría de Aldán (Galicia, north-western Spain) were studied by means of quantitative sampling and multivariate analyses. The faunal distribution was mainly conditioned by a sedimentary gradient that was defined by a decreasing grain size from the mouth towards the inner margins of the ría. Several assemblages were determined which could be defined according to the classic terms of ‘community’ and ‘facies’. A ‘Venus fasciata community’ and a ‘facies of Goodallia triangularis–Pisione parapari’ are present in coarser sandy sediments of the outer ría area. The communities characterized by ‘Venus gallina’ and ‘Tellina fabula–Tellina tenuis’ were found in the fine sand bottoms at the centre and margins of the ría. The shallower and muddier sediments in the inner ría showed a mix of typical species from the ‘Abra alba’ and the ‘Venus gallina’ communities, and in the Río Aldán's mouth could be distinguished a facies of a protected zone.

Patterns of distribution of the polychaete fauna in subtidal soft sediments of the Ría de Aldán (north-western Spain)

2008 ◽  
Vol 88 (2) ◽  
pp. 263-275 ◽  
Author(s):  
Antía Lourido ◽  
Eva Cacabelos ◽  
Jesús S. Troncoso
Keyword(s):  
Grain Size ◽  
Multivariate Analysis ◽  
Fine Sand ◽  
Medium Sand ◽  
Soft Sediments ◽  
Coarse Sediments ◽  
Western Spain ◽  
Faunal Distribution ◽  
Deposit Feeding ◽  
North Western

The composition and spatial distribution of the polychaete fauna on the subtidal soft sediments of the Ría de Aldán (Galicia, north-western Spain) were studied by means of quantitative sampling and multivariate analysis. The faunal distribution was mainly conditioned by a sediment gradient defined by decreasing grain size, from the mouth towards the inner margins of the ría. The coarse and medium sand fauna was mainly dominated by pisionids, spionids and syllids. Finer sediments (fine sand to mud) showed a greater abundance of paraonids, spionids and cirratulids and deposit feeding species. The greatest number of species and diversity were found in coarse sediments.

Macrobenthic fauna in the Ensenada de San Simón (Galicia, north-western Spain)

2008 ◽  
Vol 88 (2) ◽  
pp. 237-245 ◽  
Author(s):  
E. Cacabelos ◽  
L. Gestoso ◽  
J. Troncoso
Keyword(s):  
Grain Size ◽  
Qualitative Composition ◽  
Zostera Noltii ◽  
Intertidal Sediments ◽  
Macrobenthic Fauna ◽  
Shallow Subtidal ◽  
Soft Bottoms ◽  
Characteristic Species ◽  
Western Spain ◽  
North Western

Distribution and abundance of the macrobenthic fauna was studied in the intertidal and subtidal soft-bottoms of the Ensenada de San Simón (north-western Spain). Depth and grain size were the most important factors in determining patterns of distribution of the macrozoobenthos. A reduced Macoma community was present in the inner area of the inlet structured in two facies subdivision in the community that does not affect its qualitative composition: the first one was in intertidal areas associated with meadows of the sea grasses Zostera noltii and Z. marina and defined by the dominance of Hydrobia ulvae; the second facies in intertidal sediments was characterized by the dominance of Tubificidae and nematodes and Pseudopolydora paucibranchiata. The poverty of these bottoms in number of species can be due to salinity fluctuations and human activities developed in the area. Subtidal bottoms were characterized by a Syndosmya(=Abra)alba community. Two facies were detected: one facies located in shallow subtidal bottoms with H. ulvae and Thyasira flexuosa as characteristic species, and a second facies in deeper areas, characterized by the polychaetes Ampharete finmarchica, P. paucibranchiata, Aphelochaeta marioni, Melinna palmata and Paradoneis lyra.

scholarly journals Superficial sediments and their relation to polyehaete families in a subtropieal embayment, Mexico

2015 ◽  
pp. 237-238
Author(s):  
Nuria Méndez ◽  
María Green Ruiz
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Organic Matter Content ◽  
Fine Sand ◽  
Matter Content ◽  
Pearson’S Correlation ◽  
Pearson's Correlation ◽  
Superficial Sediments ◽  
Soft Bottoms

The soft bottoms in front of Mazatlan Bay and "Isla de la Piedra" Peninsula were studied to produce maps (depth, grain size and organic matter content in sediments). Sixty samples were óbtained with a 30 x 30 van Veen grab (4-21 m depth) and polychaetes were extracted from 21 subsamples. Grain size ranged from -1.05 phi (gravel) to 3 .81 phi (very fine sand), with fme sand predominl\ting. Organic matter content in sediment was 0.91-3.06 % (most values = 1-2 %). Thirty polychaete families (905 individuals/m2 in mean) were found, and Cirratulidae, Spionidae, Onuphidae, and Pilargiidae were domiuant. Pearson's correlation of grain size.

Trophic structure of soft-bottom macrobenthos in an inlet in north-western Spain

2009 ◽  
Vol 89 (3) ◽  
pp. 439-447 ◽  
Author(s):  
Eva Cacabelos ◽  
Marta Domínguez ◽  
Jesús S. Troncoso
Keyword(s):  
Natura 2000 ◽  
Intertidal Area ◽  
Multivariate Statistical ◽  
Surface Deposit ◽  
Deposit Feeders ◽  
Baseline Information ◽  
Soft Bottoms ◽  
Western Spain ◽  
Abundance And Distribution ◽  
North Western

The trophic composition of macrobenthic communities in intertidal and subtidal soft-bottoms of the Ensenada de San Simón (north-western Spain) was found to be related to a number of environmental variables. Distribution and abundance of trophic groups have been studied, to provide essential baseline information for monitoring the area, after its designation as a Natura 2000 Special Conservation Zone. Analyses of trophic data showed a numerical predominance of the herbivores in the inner part of the inlet, while sites at the oceanic-influenced area were numerically dominated by surface-deposit feeders. These dominances were mainly due to Hydrobia ulvae in the intertidal area and to polychaetes at the subtidal one. Both univariate and multivariate statistical analyses showed that the sediment composition (organic matter and silt–clay contents) and temperature of the bottom water influenced the benthic macrofauna and were correlated with their trophic composition, abundance and distribution.

scholarly journals Spatial distribution of bivalvia (Mollusca) in the soft-bottoms of Ilha Grande Bay, Rio de Janeiro, Brazil

1998 ◽  
Vol 46 (1) ◽  
pp. 19-31 ◽  
Author(s):  
Maria Cláudia Guimarães Grillot ◽  
Carlos Renato R. Ventura ◽  
Sérgio Henrique Gonçalves da Silva
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Rio De Janeiro ◽  
Fine Sand ◽  
Structural Heterogeneity ◽  
Coarse Sand ◽  
Bivalve Molluscs ◽  
Soft Bottoms

The spatial distribution of bivalve molluscs and its relation to granulometry and to the percentage of organic matter and silt-clay were studied in the Saco do Céu Inlet. Bivalves and samples of sediment were collected in 39 stations, in January and July 1992, using a 0.1 m2 Petersen grab. The type of sediment varied from very fine to coarse sand. Nineteen species of bivalves were quantified, 14 of which were present in the two periods of the year. The highest diversity was found in medium and fine sand in summer and in coarse sand in winter. These bottoms presented a greater structural heterogeneity. A community dominated by Corbula caribaea was distinguished in fine bottoms with relative high content of organic matter, whereas another community dominated by Anomalocardia brasiliana occurred in coarser bottoms. Both communities were distributed in continuum along a sediment gradient.

Pollens of honeys from north-western Spain

1991 ◽  
Vol 30 (2) ◽  
pp. 69-73 ◽  
Author(s):  
M V Jato ◽  
A Sala-Llinares ◽  
M I Iglesias ◽  
M Suarez-Cervera
Keyword(s):  
Western Spain ◽  
North Western

scholarly journals Remote sensing of underwater vegetation using single-beam acoustics

2009 ◽  
Vol 67 (3) ◽  
pp. 594-605 ◽  
Author(s):  
Victor Quintino ◽  
Rosa Freitas ◽  
Renato Mamede ◽  
Fernando Ricardo ◽  
Ana Maria Rodrigues ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Grain Size ◽  
Algal Biomass ◽  
Sediment Grain Size ◽  
Coastal System ◽  
Single Beam ◽  
Acoustic Data ◽  
Sediment Types ◽  
Caulerpa Prolifera ◽  
Sandy Sediments

Abstract Quintino, V., Freitas, R., Mamede, R., Ricardo, F., Rodrigues, A. M., Mota, J., Pérez-Ruzafa, Á., and Marcos, C. 2010. Remote sensing of underwater vegetation using single-beam acoustics. – ICES Journal of Marine Science, 67: 594–605. A single-beam, acoustic, ground-discrimination system (QTC VIEW, Series V) was used to study the distribution of underwater macrophytes in a shallow-water coastal system, employing frequencies of 50 and 200 kHz. The study was conducted in Mar Menor, SE Spain, where the expansion of Caulerpa prolifera has contributed to the silting up of the superficial sediments. A direct relationship was identified between algal biomass and sediment-fines content. Acoustic information on sediment grain size and data on algal biomass were obtained in muddy and sandy sediments, including vegetated and non-vegetated seabed. Non-vegetated muddy areas were created by diving and handpicking the algae. The multivariate acoustic data were analysed under the null hypotheses that there were no acoustic differences between bare seabeds with contrasting superficial sediment types or among low, medium, and high algal-biomass areas, having in mind that grain size can act as a confounding factor. Both null hypotheses were rejected, and the results showed that 200 kHz was better than 50 kHz in distinguishing cover levels of algal biomass. The relationship between the 200-kHz acoustic data and algal biomass suggests utility in modelling the latter using the former.

scholarly journals Lack of detectable genetic isolation in the cyclic rodent Microtus arvalis despite large landscape fragmentation owing to transportation infrastructures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Julio C. Dominguez ◽  
María Calero-Riestra ◽  
Pedro P. Olea ◽  
Juan E. Malo ◽  
Christopher P. Burridge ◽  
...  
Keyword(s):  
Population Density ◽  
Mixed Models ◽  
Landscape Fragmentation ◽  
Microtus Arvalis ◽  
Density Peaks ◽  
Genetic Patterns ◽  
Large Fluctuations ◽  
Genetic Impact ◽  
Western Spain ◽  
North Western

AbstractAlthough roads are widely seen as dispersal barriers, their genetic consequences for animals that experience large fluctuations in population density are poorly documented. We developed a spatially paired experimental design to assess the genetic impacts of roads on cyclic voles (Microtus arvalis) during a high-density phase in North-Western Spain. We compared genetic patterns from 15 paired plots bisected by three different barrier types, using linear mixed models and computing effect sizes to assess the importance of each type, and the influence of road features like width or the age of the infrastructure. Evidence of effects by roads on genetic diversity and differentiation were lacking. We speculate that the recurrent (each 3–5 generations) episodes of massive dispersal associated with population density peaks can homogenize populations and mitigate the possible genetic impact of landscape fragmentation by roads. This study highlights the importance of developing spatially replicated experimental designs that allow us to consider the large natural spatial variation in genetic parameters. More generally, these results contribute to our understanding of the not well explored effects of habitat fragmentation on dispersal in species showing “boom-bust” dynamics.

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