Molluscan assemblages in littoral soft bottoms of the Alboran Sea (Western Mediterranean Sea)

Urra, Javier; Gofas, Serge; Rueda, José L.; Marina, Pablo

doi:10.1080/17451001003660301

Cited by 33 publications

(40 citation statements)

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“…Structurally complex environments increase species diversity by providing more niches and different ways of exploiting environmental resources (Kerr & Packer, 1997;Gingold et al, 2010), commonly referred as the "habitat heterogeneity hypothesis" (MacArthur & Wilson, 1967). The influence of heterogeneous habitats on the increase of local biodiversity has been indicated in other Mediterranean areas, such as the Alboran Sea (Urra et al, 2011(Urra et al, , 2013a.…”

Section: Discussionmentioning

confidence: 99%

“…Three replicates per station and month were generally taken, except in May and July 2009 at 10-15 m, with a total of 65 faunistic samples. This methodology has already been used successfully in studies of soft bottom molluscan assemblages (Rueda & Salas, 2003b;Urra et al, 2011). In the laboratory, faunistic samples were sieved over mesh sizes down to 0.5 mm, then stored in 70% ethanol.…”

Section: Faunistic Samplesmentioning

confidence: 99%

“…Molluscs, together with polychaetes and crustaceans, are an important component of benthic communities, contributing extensively to the local biodiversity of habitats, such as seagrass meadows (Hemminga & Duarte, 2000;Luque & Templado, 2004), hard bottoms (Gabriele et al, 1999;Ballesteros, 2006;Casellato & Stefanon, 2008) and soft bottoms (Koulouri et al, 2006;Lourido et al, 2006;Urra et al, 2011). In the Mediterranean Sea, Coll et al (2010) recorded 2113 molluscan species that represent 20.9% of all invertebrates known to occur in this basin.…”

Section: Introductionmentioning

confidence: 99%

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Seasonality and trophic diversity in molluscan assemblages from the Bay of Tunis (southern Mediterranean Sea)

et al. 2016

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Soft bottom molluscan assemblages from the Bay of Tunis have been studied in order to analyse their seasonality and trophic diversity in relation to environmental variables. A total of 147 species of molluscs was identified, with gastropods displaying the highest species richness and bivalves the highest abundances, and including five non-indigenous species such as the dominant ectoparasite Polycerella emertoni. Carnivorous and scavenger gastropods were among the most frequent species, reflecting a diverse benthic community. Seasonal changes were significant, being more acute at 3-4 m than at 10-15 m depth, and were driven mainly by seawater temperature and percentage of organic matter in the sediment. The high affluence of tourists in summer was coincident with high decreases in species richness and abundance of molluscs, together with a strong siltation of the sediment. Nevertheless, most trophic groups remained and the trophic diversity was relatively high. Significant relationships were found between the index of trophic diversity and Shannon-Wiener diversity and evenness indices, suggesting that the identity of the species with its particular trophic trait, together with the good distribution of the individuals among the species (density) would be the drivers for the maintenance of the molluscan food web under environmental stress. The abundance of P. emertoni altered the trophic structure of the molluscan assemblage, with the ectoparasite trophic group reaching an unusual punctual higher dominance. Soft bottom molluscan assemblages of the Bay of Tunis should be taken into account in monitoring programs for anthropogenic impacts and non-indigenous species trends throughout the Mediterranean basin.

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Section: Discussionmentioning

confidence: 99%

Section: Faunistic Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seasonality and trophic diversity in molluscan assemblages from the Bay of Tunis (southern Mediterranean Sea)

et al. 2016

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“…In this context, some of the Canonical Correspondence Analyses (CCA) showed that temperature and depth, as well as certain sediment-related variables, are important for explaining the distribution of mollusc assemblages, as observed in littoral studies of molluscs and decapods carried out in the northern Alboran Sea (García Muñoz et al, 2008;Urra et al, 2011). Temperature always correlated with axis I of the CCA, and sometimes less dispersion of slope samples was detected along this axis which could be related to the thermally stable environment below 200 m in the Mediterranean Sea (Hopkins, 1985).…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, molluscs have been suggested, among other faunal groups, as proxies for assessing impacts or anthropogenic stress on total macrofaunal assemblages (Olsgard & Somerfield, 2000;Mendes et al, 2007). Studies of molluscan assemblages in the northern Alboran Sea have mainly been carried out in the infralittoral zone (soft bottoms: Urra et al, 2011;seagrass meadows: Rueda et al, 2008seagrass meadows: Rueda et al, , 2009Urra et al, 2013;rocky bottoms: Urra et al, 2012), with limited information on certain groups/species (Salas, 1996;González & Sánchez, 2002) and assemblages of the circalittoral and bathyal zone (Gofas et al, 2014a;Rueda et al, 2015). Therefore, the aims of the present study are to: (1) characterise the composition and structure of molluscan assemblages of circalittoral and bathyal sedimentary bottoms in the northern Alboran Sea using otter-trawl fishing gear, based on species analyses according to their lifestyle (i.e., demersal or benthic species) and different classes (i.e., bivalves, gastropods, and cephalopods); (2) analyse the spatial distribution patterns of these assemblages; and (3) discover which environmental variables relate to the structure and distribution of the molluscan assemblages.…”

Section: Introductionmentioning

confidence: 99%

Molluscs collected with otter trawl in the northern Alboran Sea: main assemblages, spatial distribution and environmental linkage

et al. 2018

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Molluscan assemblages of circalittoral and bathyal soft bottoms of the northern Alboran Sea were studied using an experimental otter trawl. Samples of fauna were collected from 190 hauls during four MEDITS surveys carried out in spring between 2012 and 2015 at depths ranging from 30 to 800 m. Measurements of water column variables (temperature and salinity) and sediment samples were taken in the same locations where faunistic sampling was carried out. A total of 101 species grouped in 55 families were recorded. Cephalopods were the most abundant group, with Abralia veranyi dominating in abundance, Octopus vulgaris in biomass and Illex coindetii and Todarodes sagittatus being the most frequently collected species. Multivariate analyses carried out separately with abundance data of demersal species, benthic species, bivalves, gastropods and cephalopods as well as of all molluscs, generally resulted in three main molluscan assemblages corresponding to a shelf assemblage (30-200 m depth), an upper slope assemblage (201-350 m depth), and a middle slope assemblage (351-800 m depth). PERMANOVA test revealed that significant differences of different groups of molluscs in relation to depth were more acute than to geographical sectors of the Alboran Sea (eastern, central, eastern and insular sectors). Abundance, biomass and species richness decreased with depth with a clear dominance of cephalopods in the slope. Significant geographical differences were mainly detected for demersal and benthic species as well as for gastropods and cephalopods between the insular sector (Alboran Island) and the western and eastern continental sectors. Both depth and temperature were the most influencing variables in the different CCA analyses using datasets of molluscs with different life styles and from different classes, but sedimentological variables displayed a more acute significant relationship with the benthic molluscs than with the demersal ones.

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Impact of organic matter source and quality on living benthic foraminiferal distribution on a river‐dominated continental margin: A study of the Portuguese margin

et al. 2016

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Living (rose Bengal stained) benthic foraminifera were investigated on surface sediments from 23 stations from the river-dominated northwestern Portuguese margin. Samples were collected in March 2011, following the period of the maximum rainfall over the Iberian Peninsula, between 20 and 2000 m water depth along five cross-margin transects. Four of them are located off the Douro, Mondego, Tagus, and Sado Rivers and one off the Estremadura coast. The major objectives of this study are (1) to assess the impact of organic matter of various origin and quality on the benthic foraminifera and (2) to investigate the spatial differences of faunal distribution from coastal waters to the deep sea under river influences. To do this, sedimentological and biogeochemical characteristics of the sediments were identified by measuring grain size, oxygen penetration depth, total organic carbon (TOC) content, stable carbon isotopic composition of TOC (δ 13 C TOC ) and concentration of pigments and amino acids. Based on the principal component and cluster analyses of the environmental data, three major geographical groups are identified: (1) deep stations, (2) coastal and middle slope stations, and (3) shelf stations under river influence. At the deepest stations, species are associated with high organic matter (OM) quantity but low OM quality, where Uvigerina mediterranea, Hoeglundina elegans, and agglutinated species such as Reophax scorpiurus or Bigenerina nodosaria are dominant. All stations off the Sado River, which is the most affected area by the anthropogenic influence, are also characterized by high quantity but low quality of OM with the minimum faunal density and diversity within the study area. Middle slope stations are associated with low OM content and coarse sediments (Q 50 ) with the predominance of N. scaphum. Shallow shelf stations close to the Douro and Tagus River mouths show a dominance of taxa (e.g., Ammonia beccarii, Bulimina aculeata, Eggerelloides scaber, Nonion scaphum, Cancris auriculus, and Quinqueloculina seminula) adapted to environments characterized by high OM quality (high fresh chlorophyll (Chl a/Phaeo)) and available amino acids (enzymatically hydrolyzable amino acid (EHAA)/total enzymatically hydrolyzable amino acid (THAA)). The Biotic and Environmental linking analysis suggests that the benthic foraminiferal distribution is mostly controlled by three environmental parameters, i.e., TOC (quantity), EHAA/THAA (quality), and δ 13 C TOC (source). Hence, this study clearly highlights that the quantitative and qualitative inputs of OM and its source are the most important factors controlling the living benthic foraminiferal distribution with clear influences between the different rivers. This study also suggests a good tolerance of several species for river discharges where the OM quality is high.

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Molluscan assemblages in littoral soft bottoms of the Alboran Sea (Western Mediterranean Sea)

Cited by 33 publications

References 18 publications

Seasonality and trophic diversity in molluscan assemblages from the Bay of Tunis (southern Mediterranean Sea)

Seasonality and trophic diversity in molluscan assemblages from the Bay of Tunis (southern Mediterranean Sea)

Molluscs collected with otter trawl in the northern Alboran Sea: main assemblages, spatial distribution and environmental linkage

Impact of organic matter source and quality on living benthic foraminiferal distribution on a river‐dominated continental margin: A study of the Portuguese margin

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