Impact of hydrodynamics on community structure and metabolic production of marine biofouling formed in a highly energetic estuary.

Biofouling is a specific lifestyle including both marine prokaryotic and eukaryotic communities. Hydrodynamics are poorly studied parameters affecting biofouling formation. This study aimed to investigate how water dynamics in the Etel Estuary (Northwest Atlantic coasts of France) influences the colonization of artificial substrates. Hydrodynamic conditions, mainly identified as shear stress, were characterized by measuring current velocity, turbulence intensity and energy using Acoustic Doppler Current Profiler (ADCP). One-month biofouling was analyzed by coupling metabarcoding (16S rRNA, 18S rRNA and COI genes), untargeted metabolomics (liquid chromatography coupled with high-resolution mass spectrometry, LC-HRMS) and characterization of the main biochemical components of the microbial exopolymeric matrix. A higher richness was observed for biofouling communities (prokaryotes and eukaryotes) exposed to the strongest currents. Ectopleura (Cnidaria) and its putative symbionts Endozoicomonas (Gammaproteobacteria) were dominant in the less dynamic conditions. Eukaryotes assemblages were specifically shaped by shear stress, leading to drastic changes in metabolite profiles. Under high hydrodynamic conditions, the exopolymeric matrix increased and was composed of 6 times more polysaccharides than proteins, these latter playing a crucial role in the adhesion and cohesion properties of biofilms. This original multidisciplinary approach demonstrated the importance of shear stress on both the structure of marine biofouling and the metabolic response of these complex communities.

Sediment migrations drive the dynamic of macrobenthic ecosystems in subtidal sandy bedforms.

A traditional taxonomic approach coupled to a biological traits analysis was conducted in order to provide a new insight into macrobenthic communities associated with subtidal sandy environments. Results suggest that the macro-scale distribution of benthic communities is mainly driven by the migration rate of bedforms (sandbank, barchan dune and transversal dune) which changes the sediment grain size and reduces macrobenthic diversity. A classic scheme of species/traits succession was also observed from less to more physically disturbed areas. Finally, the high frequency of migration events homogenized macrobenthic communities between the troughs to the crest of bedforms. As bedforms areas are targeted for the commissioning of offshore windfarms the information provided by the present paper will be particularly useful to implement the environmental impact assessment required for such activities at sea.

Green macroalgae blooms (Ulva spp.) influence trophic ecology of juvenile flatfish differently in sandy beach nurseries.

Opportunistic green macroalgae blooms increasingly affect coastal areas worldwide. Understanding their impacts on organisms that use this zone, such as juvenile flatfish, is critical. By combining stable isotope data, digestive tract contents and community analyses of flatfish and their potential prey (benthic macroinvertebrates) from two North-East Atlantic sandy beaches (one impacted by blooms and one not), we detected similar and species-specific trophic changes among three co-occurring species (sand sole, plaice and turbot). Across flatfish species, juveniles displayed more opportunistic foraging behavior at the impacted site. Differently, plaice and sand sole relied more on the additional basal resource (Ulva spp.) than turbot. Finally, sand sole and turbot presented a stronger diet shift at the impacted site than plaice. We hypothesize that the species-specific response to the blooms are mostly driven by how the flatfish detect their prey (using visual and/or chemical cues) and when they forage (diurnal or nocturnal foraging).

Dataset on marine ecosystem services supplied by coral reefs, sandy beaches and coastal lagoons in different eutrophication states.

This data article provides indicators of Ecosystem Service (ES) supply for coral reefs, sandy beaches and coastal lagoons in different ecological states regarding eutrophication. 14 ES are considered: food through fisheries; material; molecules; coastal protection; nutrient regulation; pathogen regulation; climate regulation; support of recreational and leisure activities; contribution to a pleasant landscape; contribution to culture and territorial identity; emblematic biodiversity; habitat; trophic networks; recruitment. For each ecosystem 3 to 4 eutrophication states are described. Indicators of ES supply are filled on the basis of a literature review supplemented with expert-knowledge. A semi-quantification of the indicator value is finally provided. Tendencies and trade-offs between ES are analyzed in How does eutrophication impact bundles of ecosystem services in multiple coastal habitats using state-and-transition models [1].