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Auteur Moreau, S.; Mostajir, B.; Bélanger, S.; Schloss, I.R.; Vancoppenolle, M.; Demers, S.; Ferreyra, G.A.
Titre Climate change enhances primary production in the western Antarctic Peninsula Type Article scientifique
Année 2015 Publication Revue Abrégée Glob Change Biol
Volume 21 Numéro 6 Pages 2191-2205
Mots-Clés ozone hole; photoinhibition; primary production; regional warming; sea ice; seawater temperature; ultraviolet radiation
Résumé Intense regional warming was observed in the western Antarctic Peninsula (WAP) over the last 50 years. Here, we investigate the impact of climate change on primary production (PP) in this highly productive region. This study is based on temporal data series of ozone thickness (1972–2010), sea ice concentration (1978–2010), sea-surface temperature (1990–2010), incident irradiance (1988–2010) and satellite-derived chlorophyll a concentration (Chl-a, 1997–2010) for the coastal WAP. In addition, we apply a photosynthesis/photoinhibition spectral model to satellite-derived data (1997–2010) to compute PP and examine the separate impacts of environmental forcings. Since 1978, sea ice retreat has been occurring earlier in the season (in March in 1978 and in late October during the 2000s) while the ozone hole is present in early spring (i.e. August to November) since the early 1990s, increasing the intensity of ultraviolet-B radiation (UVBR, 280–320 nm). The WAP waters have also warmed over 1990–2010. The modelled PP rates are in the lower range of previously reported PP rates in the WAP. The annual open water PP in the study area increased from 1997 to 2010 (from 0.73 to 1.03 Tg C yr−1) concomitantly with the increase in the production season length. The coincidence between the earlier sea ice retreat and the presence of the ozone hole increased the exposure to incoming radiation (UVBR, UVAR and PAR) and, thus, increased photoinhibition during austral spring (September to November) in the study area (from 0.014 to 0.025 Tg C yr−1). This increase in photoinhibition was minor compared to the overall increase in PP, however. Climate change hence had an overall positive impact on PP in the WAP waters.
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ISSN 1365-2486 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1339
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Auteur Reynolds, P.L.; Stachowicz, J.J.; Hovel, K.; Bostrom, C.; Boyer, K.; Cusson, M.; Eklof, J.S.; Engel, F.G.; Engelen, A.H.; Eriksson, B.K.; Fodrie, F.J.; Griffin, J.N.; Hereu, C.M.; Hori, M.; Hanley, T.C.; Ivanov, M.; Jorgensen, P.; Kruschel, C.; Lee, K.-S.; McGlathery, K.; Moksnes, P.-O.; Nakaoka, M.; O'Connor, M.I.; O'Connor, N.E.; Orth, R.J.; Rossi, F.; Ruesink, J.; Sotka, E.E.; Thormar, J.; Tomas, F.; Unsworth, R.K.F.; Whalen, M.A.; Duffy, J.E.
Titre Latitude, temperature, and habitat complexity predict predation pressure in eelgrass beds across the Northern Hemisphere Type Article scientifique
Année 2018 Publication Revue Abrégée Ecology
Volume 99 Numéro 1 Pages 29-35
Mots-Clés patterns; communities; diversity; ecosystems; temperature; seagrasses; eutrophication; predation; biogeography; prey; top-down control; enrichment; latitude; mesograzer; seagrass; species interactions; water temperature; Zostera
Résumé Latitudinal gradients in species interactions are widely cited as potential causes or consequences of global patterns of biodiversity. However, mechanistic studies documenting changes in interactions across broad geographic ranges are limited. We surveyed predation intensity on common prey (live amphipods and gastropods) in communities of eelgrass (Zostera marina) at 48 sites across its Northern Hemisphere range, encompassing over 37 degrees of latitude and four continental coastlines. Predation on amphipods declined with latitude on all coasts but declined more strongly along western ocean margins where temperature gradients are steeper. Whereas insitu water temperature at the time of the experiments was uncorrelated with predation, mean annual temperature strongly positively predicted predation, suggesting a more complex mechanism than simply increased metabolic activity at the time of predation. This large-scale biogeographic pattern was modified by local habitat characteristics; predation declined with higher shoot density both among and within sites. Predation rates on gastropods, by contrast, were uniformly low and varied little among sites. The high replication and geographic extent of our study not only provides additional evidence to support biogeographic variation in predation intensity, but also insight into the mechanisms that relate temperature and biogeographic gradients in species interactions.
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Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0012-9658 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2254
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