• Energy Research

Marinas are hubs for non-indigenous species (NIS) and constitute the nodes of a network of highly modified water bodies (HMWB) connected by recreational maritime traffic. Floating structures, such as pontoons, are often the surfaces with higher NIS abundance inside marinas and lead the risk for NIS introduction, establishment and spread. However, there is still little information on how the location within the marina and the substratum type can influence the recruitment of fouling assemblages depending on water parameters and substratum chemical composition. In this study, fouling recruitment was studied using an experimental approach with three materials (basalt, concrete and HDPE plastic) in two sites (close and far to the entrance) in two marinas of Madeira Island (NE Atlantic, Portugal). The structure of benthic assemblages after 6- and 12-months colonization, as well as biotic abundance, NIS abundance, richness, diversity, assemblages' volume, biomass and assemblages' morphology were explored. Differences between marinas were the main source of variation for both 6- and 12-month assemblages, with both marinas having different species composition and biomass. The inner and outer sites of both marinas varied in terms of structure and heterogeneity of assemblages and heterogeneity of morphological traits, but assemblages did not differ among substrata. However, basalt had a higher species richness and diversity while concrete showed a higher bioreceptivity in terms of total biotic coverage than the rest of materials. Overall, differences between and within marinas could be related to their structural morphology. This study can be valuable for management of urban ecosystems, towards an increase in the environmental and ecological status of existing marinas and their HMWB and mitigation coastal ecosystems degradation.

AbstractClimate change is causing an increase in the frequency and intensity of marine heatwaves (MHWs) and mass mortality events (MMEs) of marine organisms are one of their main ecological impacts. Here, we show that during the 2015–2019 period, the Mediterranean Sea has experienced exceptional thermal conditions resulting in the onset of five consecutive years of widespread MMEs across the basin. These MMEs affected thousands of kilometers of coastline from the surface to 45 m, across a range of marine habitats and taxa (50 taxa across 8 phyla). Significant relationships were found between the incidence of MMEs and the heat exposure associated with MHWs observed both at the surface and across depths. Our findings reveal that the Mediterranean Sea is experiencing an acceleration of the ecological impacts of MHWs which poses an unprecedented threat to its ecosystems' health and functioning. Overall, we show that increasing the resolution of empirical observation is critical to enhancing our ability to more effectively understand and manage the consequences of climate change.

This study was implemented to assess the Sessile Bioindicators in Permanent Quadrats (SBPQ) underwater environmental alert method. The SBPQ is a non-invasive and low-cost protocol; it uses sessile target species (indicators) to detect environmental alterations (natural or anthropic) at either the local or global (i.e., climate change) scale and the intrusion of invasive species. The SBPQ focuses on the monitoring of preselected sessile and sensitive benthic species associated with rocky coralligenous habitats using permanent quadrats in underwater sentinel stations. The selected target species have been well documented as bioindicators that disappear in the absence of environmental stability. However, whether these species are good indicators of stability or, in contrast, suffer variations in long-term coverage has not been verified. The purpose of this study was to assess the part of the method based on the hypothesis that, over a long temporal series in a highly structured and biodiverse coralligenous assemblage, the cover of sensitive sessile species does not change over time if the environmental stability characterising the habitat is not altered. Over a ten-year period (2005-2014), the sublittoral sessile biota in the Straits of Gibraltar Natural Park on the southern Iberian Peninsula was monitored at a 28 m-deep underwater sentinel stations. Analyses of the coverages of target indicator species (i.e., Paramuricea clavata and Astroides calycularis) together with other accompanying sessile organisms based on the periodic superimposition of gridded images from horizontal and vertical rocky surfaces allowed us to assess the effectiveness of the method. We conclude that no alterations occurred during the study period; only minimal fluctuations in cover were detected, and the method is reliable for detecting biological changes in ecosystems found in other geographical areas containing the chosen indicator species at similar dominance levels.

The Mediterranean region is a climate change hotspot, where the respective impacts of warming are very pronounced and relatively well documented. One of the major impacts of sea surface temperature rise in the marine coastal ecosystems is the occurrence of mass mortality events (MMEs). The Mass Mortality Events (MME) database reported here is a collaborative initiative involving more than 30 research institutions from 10 Mediterranean countries including EU and non-EU countries. This initiative aims to facilitate the access to information (published in scientific journals and gray literature or still unpublished) related to Mediterranean MMEs. The main objectives of the initiative are to (i) assemble and standardize existing information on MMEs ; (ii) identify geographic gaps that need to be addressed through future monitoring and research efforts ; (iii) assess species vulnerability to MMEs and identify observation taxonomic gaps ; (iv) foster the analysis of the relationship between MMEs and environmental conditions, with an emphasis on marine heat waves ; (v) provide an unrestricted, open-source and easy access dataset ; (vi) ensure transparency and clarity regarding the origin of each dataset and adequate data citation and (vii) provide information for the assessment of the impact of MMEs on the biodiversity and socio-economic activities.