Atlas de las praderas marinas de España

Knowledge of the distribution and extent of seagrass habitats is currently the basis of management and conservation policies of the coastal zones in most European countries. This basic information is being requested through European directives for the establishment of monitoring programmes and the implementation of specific actions to preserve the marine environment. In addition, this information is crucial for the quantification of the ecological importance usually attributed to seagrass habitats due to, for instance, their involvement in biogeochemical cycles, marine biodiversity and quality of coastal waters or global carbon budgets. The seagrass atlas of Spain represents a huge collective effort performed by 84 authors across 30 Spanish institutions largely involved in the scientific research, management and conservation of seagrass habitats during the last three decades. They have contributed to the availability of the most precise and realistic seagrass maps for each region of the Spanish coast which have been integrated in a GIS to obtain the distribution and area of each seagrass species. Most of this information has independently originated at a regional level by regional governments, universities and public research organisations, which explain the elevated heterogeneity in criteria, scales, methods and objectives of the available information. On this basis, seagrass habitats in Spain occupy a total surface of 1,541,63 km2, 89% of which is concentrated in the Mediterranean regions; the rest is present in sheltered estuarine areas of the Atlantic peninsular regions and in the open coastal waters of the Canary Islands, which represents 50% of the Atlantic meadows. Of this surface, 71.5% corresponds to Posidonia oceanica, 19.5% to Cymodocea nodosa, 3.1% to Zostera noltii (=Nanozostera noltii), 0.3% to Zostera marina and 1.2% to Halophila decipiens. Species distribution maps are presented (including Ruppia spp.), together with maps of the main impacts and pressures that has affected or threatened their conservation status, as well as the management tools established for their protection and conservation. Despite this considerable effort, and the fact that Spain has mapped wide shelf areas, the information available is still incomplete and with weak precision in many regions, which will require an investment of major effort in the near future to complete the whole picture and respond to demands of EU directives.Versión del edito

Warming and CO2 Enhance Arctic Heterotrophic Microbial Activity

Ocean acidification and warming are two main consequences of climate change that can directly affect biological and ecosystem processes in marine habitats. The Arctic Ocean is the region of the world experiencing climate change at the steepest rate compared with other latitudes. Since marine planktonic microorganisms play a key role in the biogeochemical cycles in the ocean it is crucial to simultaneously evaluate the effect of warming and increasing CO2 on marine microbial communities. In 20 L experimental microcosms filled with water from a high-Arctic fjord (Svalbard), we examined changes in phototrophic and heterotrophic microbial abundances and processes [bacterial production (BP) and mortality], and viral activity (lytic and lysogenic) in relation to warming and elevated CO2. The summer microbial plankton community living at 1.4◦C in situ temperature, was exposed to increased CO2 concentrations (135–2,318 µatm) in three controlled temperature treatments (1, 6, and 10◦C) at the UNIS installations in Longyearbyen (Svalbard), in summer 2010. Results showed that chlorophyll a concentration decreased at increasing temperatures, while BP significantly increased with pCO2 at 6 and 10◦C. Lytic viral production was not affected by changes in pCO2 and temperature, while lysogeny increased significantly at increasing levels of pCO2, especially at 10◦C (R 2 = 0.858, p = 0.02). Moreover, protistan grazing rates showed a positive interaction between pCO2 and temperature. The averaged percentage of bacteria grazed per day was higher (19.56 ± 2.77% d−1 ) than the averaged percentage of lysed bacteria by virus (7.18 ± 1.50% d−1 ) for all treatments. Furthermore, the relationship among microbial abundances and processes showed that BP was significantly related to phototrophic pico/nanoflagellate abundance in the 1 ◦C and the 6◦C treatments, and BP triggered viral activity, mainly lysogeny at 6 and 10◦C, while bacterial mortality rates was significantly related to bacterial abundances at 6 ◦C. Consequently, our experimental results suggested that future increases in water temperature and pCO2 in Arctic waters will produce a decrease of phytoplankton biomass, enhancement of BP and changes in the carbon fluxes within the microbial food web. All these heterotrophic processes will contribute to weakening the CO2 sink capacity of the Arctic plankton community

Density dependence in marine protected populations: A review

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Recent trends reversal for declimimg European seagrass meadows

Seagrass meadows, key ecosystems supporting fisheries, carbon sequestration and coastal protection, are globally threatened. In Europe, loss and recovery of seagrasses are reported, but the changes in extent and density at the continental scale remain unclear. Here we collate assessments of changes from 1869 to 2016 and show that 1/3 of European seagrass area was lost due to disease, deteriorated water quality, and coastal development, with losses peaking in the 1970s and 1980s. Since then, loss rates slowed down for most of the species and fastgrowing species recovered in some locations, making the net rate of change in seagrass area experience a reversal in the 2000s, while density metrics improved or remained stable in most sites. Our results demonstrate that decline is not the generalised state among seagrasses nowadays in Europe, in contrast with global assessments, and that deceleration and reversal of declining trends is possible, expectingly bringing back the services they provide

Spillover from six western Mediterranean marine protected areas: evidence from artisanal fisheries

This study investigated spillover (biomass export) around 6 marine protected areas (MPAs) in the western Mediterranean based on catch and effort data from artisanal fisheries. The selected MPAs were Cerbère-Banyuls and Carry-le-Rouet in France, and Medes, Cabrera, Tabarca, and Cabo de Palos in Spain. These MPAs had been functional for more than 8 yr and incorporate areas of fisheries closure and restricted use where fishing is limited. We based our study on the hypotheses that, in the presence of biomass export, (1) fishing effort would concentrate close to MPA boundaries, and (2) fishery production, expressed as catch per unit area (CPUA), would be highest near MPA boundaries and decrease with distance. We selected data from 14 ‘fishing tactics’ using gill nets, trammel nets and bottom long-lines targeting sparids, mullids, serranids, scorpaenids and palinurids. We analyzed the spatial distribution of effort, fishery production and revenues per unit area, using generalized additive models (GAMs), and we tested regression slopes of effort density and CPUA with distance to closure boundaries, using generalized linear models (GLMs). GAMs allowed us to recognize habitat discontinuities or ‘hot spots’ of high production in the vicinity of the MPAs, and to identify the extent of potential spillover effects in order to implement GLMs. We found evidence of effort concentration and high fishery production near fisheries closures for all fishing tactics analyzed and significant negative slopes for most. Revenues generally followed trends similar to CPUA. Significant negative slopes from GLM of effort density and CPUA with distance from fisheries closures were indicative of biomass export where habitats across closure boundaries had some degree of continuity. The spatial extent of spillover was consistent with species mobility and fisheries efficiency and extended 700 to 2500 m from fishery closure boundaries. Our results suggest that coastal MPAs can be an effective management tool for artisanal fisheries in the region and can be extended to the rest of the western Mediterranean, as the fishing tactics studied are typical of the regionPublicado