522 resultados para Marius Barbeau
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The response of the coccolithophore Emiliania huxleyi to rising CO2 concentrations is well documented for acclimated cultures where cells are exposed to the CO2 treatments for several generations prior to the experiment. The exact number of generations required for acclimation to CO2-induced changes in seawater carbonate chemistry, however, is unknown. Here we show that Emiliania huxleyi's short-term response (26 h) after cultures (grown at 500 µatm) were abruptly exposed to changed CO2 concentrations (~190, 410, 800 and 1500 ?atm) is similar to that obtained with acclimated cultures under comparable conditions in earlier studies. Most importantly, from the lower CO2 levels (190 and 410 ?atm) to 750 and 1500 µatm calcification decreased and organic carbon fixation increased within the first 8 to 14 h after exposing the cultures to changes in carbonate chemistry. This suggests that Emiliania huxleyi rapidly alters the rates of essential metabolical processes in response to changes in seawater carbonate chemistry, establishing a new physiological "state" (acclimation) within a matter of hours. If this relatively rapid response applies to other phytoplankton species, it may simplify interpretation of studies with natural communities (e.g. mesocosm studies and ship-board incubations), where often it is not feasible to allow for a pre-conditioning phase before starting experimental incubations.
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The physiological performance of two coccolithophore species,Emiliania huxleyi and Coccolithus braarudii, was investigated during long-term exposure to elevated pCO2 levels. Mono-specific cultures were grown over 152 (E. huxleyi) and 65 (C. braarudii) generations while pCO2 was gradually increased to maximum levels of 1150 ?atm (E. huxleyi) and 930 ?atm (C. braarudii) and kept constant thereafter. Rates of cell growth and cell quotas of particulate organic carbon (POC), particulate inorganic carbon (PIC) and total particulate nitrogen (TPN) were determined repeatedly throughout the incubation period. Increasing pCO2 caused a decrease in cell growth rate of 9% and 29% in E. huxleyi and C. braarudii, respectively. In both species cellular PIC:TPN and PIC:POC ratios decreased in response to rising pCO2, whereas no change was observed in the POC:TPN ratios of E. huxleyi and C. braarudii. These results are consistent with those obtained in shorter-term high CO2exposure experiments following abrupt pertubations of the seawater carbonate system and indicate that for the strains tested here a gradual CO2 increase does not alleviate CO2/pH sensitivity.
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The exponential growth of studies on the biological response to ocean acidification over the last few decades has generated a large amount of data. To facilitate data comparison, a data compilation hosted at the data publisher PANGAEA was initiated in 2008 and is updated on a regular basis (doi:10.1594/PANGAEA.149999). By January 2015, a total of 581 data sets (over 4 000 000 data points) from 539 papers had been archived. Here we present the developments of this data compilation five years since its first description by Nisumaa et al. (2010). Most of study sites from which data archived are still in the Northern Hemisphere and the number of archived data from studies from the Southern Hemisphere and polar oceans are still relatively low. Data from 60 studies that investigated the response of a mix of organisms or natural communities were all added after 2010, indicating a welcomed shift from the study of individual organisms to communities and ecosystems. The initial imbalance of considerably more data archived on calcification and primary production than on other processes has improved. There is also a clear tendency towards more data archived from multifactorial studies after 2010. For easier and more effective access to ocean acidification data, the ocean acidification community is strongly encouraged to contribute to the data archiving effort, and help develop standard vocabularies describing the variables and define best practices for archiving ocean acidification data.
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About 50 locations ('cold spots') where permafrost (Arctic and Antarctic) in situ monitoring has been taking place for many years or where field stations are currently established (through, for example the Canadian ADAPT program) have been identified. These sites have been proposed to WMO Polar Space Task Group as focus areas for future monitoring by satellite data. Seven monitoring transects spanning different permafrost types have been proposed in addition.
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Our approach emphasizes on the importance of the first forms of salt springs exploitation meant to obtain recrystallized salt for the development of prehistoric human communities within the continental inlands of Europe. Although it does not compare with the monumental dimension of World Heritage, the exploitation of some salt springs in Eastern Romania goes back around 8 millennia; they may be the oldest such exploitations in the world, as proven by 14C calibrated data. What differentiates Romanian salt springs from other famous similar areas in Europe is the continuity of exploitation and utilization of natural brine. Actually, these resilient behaviours explain the creation of a whole and complex universe of salt, which also represents a unique point of reference within the intangible World Heritage. It is through this association in variable proportions between tangible (non-monumental) and intangible that these salt springs comprising the oldest traces of salt exploitation can be considered elements of World Heritage. Today, important personalities in the fields of archaeology, anthropology and history posit that salt is a major reference for the development of the entire umanity. Obviously, the breakthrough of this idea requires awareness efforts targeting, on one hand, local communities in those areas wand, on the other, national and international scientific and cultural environments concerned with the World Heritage. In this context, a proper motivation is the fact that the last two decades have witnessed an intensification of research on salt, which turned this topic one of the major themes within European archaeology and ethno-archaeology. In terms of local community awareness concerning the importance of salt springs in the economic development of a (micro) area over time, it is worth underlining mostly the specialists’ efforts of presenting this topic in the media. Moreover, the impact of a recent initiative of the two museums in the area (Piatra Neamț and Târgu Neamț)—establishing distinct sections that represent, by using museum-inspired means, both archaeological vestiges and traditional practices of natural brine exploitation and utilization—will prove its extent in time. Certain local authorities and private entrepreneurs have pinpointed that valorising tourist areas comprising the oldest traces of salt exploitation in Romania is an imminent issue. The greatest challenge is finding a balance between the civilization improvements (upgraded access roads, upgrading operating areas, etc.) and thep rotection of still-alive traditional practices of salt exploitation and use, within rural areas. Certain local authorities and private entrepreneurs have pinpointed that valorising tourist areas comprising the oldest traces of salt exploitation in Romania will become, sooner or later, an imminent issue. The greatest challenge is finding a balance between the civilization improvements (upgraded access roads, upgrading operating areas, etc.) and the protection of still-alive traditional practices of salt exploitation and use, within rural areas.
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Acknowledgements This study was funded by a BBSRC studentship (MA Wenzel) and NERC grants NE/H00775X/1 and NE/D000602/1 (SB Piertney). The authors are grateful to Fiona Leckie, Andrew MacColl, Jesús Martínez-Padilla, François Mougeot, Steve Redpath, Pablo Vergara† and Lucy M.I. Webster for samples; Keliya Bai, Daisy Brickhill, Edward Graham, Alyson Little, Daniel Mifsud, Lizzie Molyneux and Mario Röder for fieldwork assistance; Gillian Murray-Dickson and Laura Watt for laboratory assistance; Heather Ritchie for helpful comments on manuscript drafts; and all estate owners, factors and keepers for access to field sites, most particularly Stuart Young and Derek Calder (Edinglassie), Simon Blackett, Jim Davidson and Liam Donald (Invercauld and Glas Choille), Richard Cooke and Fred Taylor† (Invermark) and T. Helps (Catterick).
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Peer reviewed
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Peer reviewed
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Date of Acceptance: 30/8/15 Acknowledgements We thank the chief scientists, crew and company of the Japanese RV Hakuho-Maru (KH0703 and KH0803), the RV Tansei-Maru (KT-09-03), the RV Kairei (KR0716), the German FS Sonne (SO197 and SO 209) and the New Zealand RV Kaharoa (KAH0190, KAH1109, KAH1202, KAH1301 and KAH1310). This work was supported by the HADEEP projects, funded by the Nippon Foundation, Japan (2009765188), the Natural Environmental Research Council, UK (NE/E007171/1) and the Total Foundation, France. We acknowledge additional support from the Marine Alliance for Science and Technology for Scotland (MASTS) funded by the Scottish Funding Council (Ref: HR09011) and contributing institutions. We also acknowledge support from the Leverhulme Research Fellowship granted to SBP. Additional sea time was supported by NIWA’s ‘Impact of Resource Use on Vulnerable Deep-Sea Communities’ project (CO1_0906). From NIWA we thank Malcolm Clark, Ashley Rowden, Kareen Schnabel, Sadie Mills for logistical support at the NIWA Invertebrate Collection. We also thank Fredrik Søreide from Promare, USA, for supply of the Puerto-Rico samples, Marius Wenzel for helpful comments on manuscript drafts, and Dr. Tammy Horton (NOCS, UK) for identifying some of the earlier amphipod samples
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This article is protected by copyright. All rights reserved. Acknowledgements This study was funded by a BBSRC studentship (MAW) and NERC grants NE/H00775X/1 and NE/D000602/1 (SBP). The authors are grateful to Mario Röder and Keliya Bai for fieldwork assistance, and all estate owners, factors and keepers for access to field sites, most particularly MJ Taylor and Mike Nisbet (Airlie), Neil Brown (Allargue), RR Gledson and David Scrimgeour (Delnadamph), Andrew Salvesen and John Hay (Dinnet), Stuart Young and Derek Calder (Edinglassie), Kirsty Donald and David Busfield (Glen Dye), Neil Hogbin and Ab Taylor (Glen Muick), Alistair Mitchell (Glenlivet), Simon Blackett, Jim Davidson and Liam Donald (Invercauld), Richard Cooke and Fred Taylor† (Invermark), Shaila Rao and Christopher Murphy (Mar Lodge), and Ralph Peters and Philip Astor (Tillypronie). Data accessibility • Genotype data (DataDryad: doi:10.5061/dryad.4t7jk) • Metadata (information on sampling sites, phenotypes and medication regimen) (DataDryad: doi:10.5061/dryad.4t7jk)
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Acknowledgements This study was supported by a grant from the Luxembourg Fonds National de la Recherche (VIVRE FNR/06/09/18) and a PhD scholarship awarded to the first author by the Fonds National de la Recherche.
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Peer reviewed
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This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Acknowledgements The authors would like to thank Dr Marius Sudol for the hYAP plasmids (obtained through Addgene), Dr Pete Zammit for the pMSCV-IRES-eGFP plasmid, Dr Robert Judson for subcloning the hYAP cDNAs into the pMSCV-IRES-eGFP plasmid, Dr Lynda Erskine for the provision of mouse embryo samples, and Professor Jimmy Hutchison and the Orthopaedics Department at the Aberdeen Royal Infirmary for the provision of human tissue samples. The authors are also grateful to Denise Tosh and Susan Clark for excellent technical support. This work was funded by Arthritis Research UK (grant 19429).
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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.