%0 Journal Article %J Journal of Marine Systems %D 2014 %T Large and local-scale influences on physical and chemical characteristics of coastal waters of Western Europe during winter %A Paul Tréguer %A Goberville, Eric %A Barrier, Nicolas %A Stéphane L'Helguen %A Morin, Pascal %A Bozec, Yann %A Rimmelin-Maury, Peggy %A Czamanski, Marie %A Emilie Grossteffan %A Cariou, Thierry %A Répécaud, Michel %A Quéméner, Loic %K Climate variability %K Coastal systems %K Large-scale hydro-climatic indices %K River inputs %K Time-series %K Weather regimes %X

There is now a strong scientific consensus that coastal marine systems of Western Europe are highly sensitive to the combined effects of natural climate variability and anthropogenic climate change. However, it still remains challenging to assess the spatial and temporal scales at which climate influence operates. While large-scale hydro-climatic indices, such as the North Atlantic Oscillation (NAO) or the East Atlantic Pattern (EAP) and the weather regimes such as the Atlantic Ridge (AR), are known to be relevant predictors of physical processes, changes in coastal waters can also be related to local hydro-meteorological and geochemical forcing. Here, we study the temporal variability of physical and chemical characteristics of coastal waters located at about 48°N over the period 1998-2013 using (1) sea surface temperature, (2) sea surface salinity and (3) nutrient concentration observations for two coastal sites located at the outlet of the Bay of Brest and off Roscoff, (4) river discharges of the major tributaries close to these two sites and (5) regional and local precipitation data over the region of interest. Focusing on the winter months, we characterize the physical and chemical variability of these coastal waters and document changes in both precipitation and river runoffs. Our study reveals that variability in coastal waters is connected to the large-scale North Atlantic atmospheric circulation but is also partly explained by local river influences. Indeed, while the NAO is strongly related to changes in sea surface temperature at the Brest and Roscoff sites, the EAP and the AR have a major influence on precipitations, which in turn modulate river discharges that impact sea surface salinity at the scale of the two coastal stations. © 2014 Elsevier B.V.

%B Journal of Marine Systems %V 139 %P 79–90 %G eng %0 Journal Article %J PLoS ONE %D 2013 %T Decline in Kelp in West Europe and Climate %A Virginie Raybaud %A Grégory Beaugrand %A Goberville, Eric %A Delebecq, Gaspard %A Destombe, Christophe %A Valero, Myriam %A Dominique Davoult %A Morin, Pascal %A Gevaert, Francois %X

Kelp ecosystems form widespread underwater forests playing a major role in structuring the biodiversity at a regional scale. Some seaweeds such as Laminaria digitata are also economically important, being exploited for their alginate and iodine content. Although some studies have shown that kelp ecosystems are regressing and that multiple causes are likely to be at the origin of the disappearance of certain populations, the extent to which global climate change may play a role remains speculative. Here we show that many populations of L. digitata along European coasts are on the verge of local extinction due to a climate-caused increase in sea temperature. By modeling the spatial distribution of the seaweed, we evaluate the possible implications of global climate change for the geographical patterns of the species using temperature data from the Coupled Model Intercomparison Project phase 5 (CMIP5). Projections of the future range of L. digitata throughout the 21st century show large shifts in the suitable habitat of the kelp and a northward retreat of the southern limit of its current geographic distribution from France to Danish coasts and the southern regions of the United Kingdom. However, these projections depend on the intensity of warming. A medium to high warming is expected to lead to the extirpation of the species as early as the first half of the 21st century and there is high confidence that regional extinction will spread northwards by the end of this century. These changes are likely to cause the decline of species whose life cycle is closely dependent upon L. digitata and lead to the establishment of new ecosystems with lower ecological and economic values.

%B PLoS ONE %V 8 %G eng