Browsing by Author "Dutrieux, Eric"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Description of the new species Sigambra nkossa (Annelida, Pilargidae), with an analysis of the distribution patterns of polychaetes associated with artificially hydrocarbon-enriched bottomsPublication . Martin, Daniel; Gil, João; Chaineau, Claude-Henri; Thorin, Sébastien; Le Gall, Romain; Dutrieux, EricThe monitoring of the N'Kossa offshore oil and gas fields in the Republic of Congo allowed us to assess the ecological traits of two polychaete species belonging to Sigambra (Annelida, Pilargidae). Sigambra parva occur in very low densities in all bottoms, except the most impacted, where it is totally absent; it is an undescribed species that reached >4,000 ind/m(2) in hydrocarbon-enriched sediments. Their distribution patterns are compared with those of other polychaetes, showing a range of affinities for hydrocarbon-enriched sediments in the N'Kossa region. Our results suggest that S. parva would be a representative of the original local fauna, while the species associated with artificial hydrocarbon-enriched sediments, including the other Sigambra, six more polychaetes and a bivalve, could be natively associated with natural hydrocarbon-enriched sediments, using the former as alternative habitats and as dispersal stepping stones. This ecological segregation, together with a careful morphological and morphometric analyses led us to describe the latter as a new species, namely Sigambra nkossa sp. nov. Moreover, morphometric analysis allowed us to discuss on the taxonomic robustness of the key morphological characters of S. nkossa sp. nov., as well as to emend the generic diagnosis of Sigambra to accommodate the new species.
- Long-distance influence of the Rhone River plume on the marine benthic ecosystem: Integrating descriptive ecology and predictive modellingPublication . Martin, Daniel; Pititto, Francesco; Gil, João; Paola Mura, Maria; Bahamon, Nixon; Romano, Chiara; Thorin, Sebastien; Schvartz, Thibault; Dutrieux, Eric; Bocquenet, YannickThe Gulf of Lions (GoL) is among the most productive areas of the Mediterranean Sea, with the Rhone River contributing with as much as 90% of the liquid and solid materials (including anthropogenic chemicals) reaching the area. In this paper, we assessed whether classical descriptive ecology and MaxEnt predictive species distribution modelling were able to provide complementary information when analysing the long-distance influence of the river discharges on the GoL benthic ecosystem. Samples were collected in August 2014 from 12 stations covering the sedimentary plain of the deep submarine delta, from the Gulf of Fos to Gruissan. Sediments were mostly muddy with a high organic carbon and low P and N contents first decreasing and then increasing from east to west. The same pattern occurred for chlorophyll-a, particulate organic carbon and sea surface temperature, and was overall correlated with metal and pollutant contents derived from agricultural, port, urban and industrial sources driven by Rhone outputs. We observed a typical deltaic succession in the benthos, showing a relatively low diversity and including polychaetes (Sternaspis scutata) and holothurians (Oestergrenia digitata) known to be indicators of high sedimentation rates. Overall, benthos showed an inversed pattern regarding environmental variables, an evident consequence of the Rhone River influence. The suitability of some species was either positively or negatively correlated with some of the environmental variables, producing species-specific predicted distribution patterns, with the highest amount of information allowing to predict distributions being mainly provided by organic pollutants. Even with a limited number of available samples, our integrated approach reveals to be a very robust tool to highlight hidden patterns and contributes to improve our knowledge on how river mediated anthropogenic discharges may influence biodiversity distribution and functional patterns in marine benthic ecosystems. (C) 2019 Elsevier B.V. All rights reserved.