georefid:2012-101388SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1130/G33388.12012-01-01publicationgeorefid:2012-101388doi:10.1130/G33388.1Edgar, K. M.University of Southampton, National Oceanography Centre Southampton, Southampton, United KingdomauthorBohaty, S. M.Scripps Institution of Oceanography, United StatesauthorGibbs, S. J.authorSexton, P. F.authorNorris, R. D.authorWilson, P. A.authorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)41 (1)15-18Many genera of modern planktic foraminifera are adapted to nutrient-poor (oligotrophic) surface waters by hosting photosynthetic symbionts, but it is unknown how they will respond to future changes in ocean temperature and acidity. Here we show that ca. 40 Ma, some fossil photosymbiont-bearing planktic foraminifera were temporarily 'bleached' of their symbionts coincident with transient global warming during the Middle Eocene Climatic Optimum (MECO). At Ocean Drilling Program (ODP) Sites 748 and 1051 (Southern Ocean and mid-latitude North Atlantic, respectively), the typically positive relationship between the size of photosymbiont-bearing planktic foraminifer tests and their carbon isotope ratios (delta (super 13) C) was temporarily reduced for approximately 100 k.y. during the peak of the MECO. At the same time, the typically photosymbiont-bearing planktic foraminifera Acarinina suffered transient reductions in test size and relative abundance, indicating ecological stress. The coincidence of minimum delta (super 18) O values and reduction in test size-delta (super 13) C gradients suggests a link between increased sea-surface temperatures and bleaching during the MECO, although changes in pH and nutrient availability may also have played a role. Our findings show that host-photosymbiont interactions are not constant through geological time, with implications for both the evolution of trophic strategies in marine plankton and the reliability of geochemical proxy records generated from symbiont-bearing planktic foraminifera.completedStratigraphyIsotope geochemistryAcarininaAtlantic OceanBlake NoseBlake PlateauC-13/C-12carbonCenozoicEoceneForaminiferaIndian OceanInvertebrataisotope ratiosisotopesKerguelen PlateauLeg 120Leg 171Bmicrofossilsmiddle Eocenemiddle Eocene climatic optiumNorth AtlanticO-18/O-16Ocean Drilling ProgramODP Site 1051ODP Site 748oxygenpaleoclimatologypaleoecologypaleoenvironmentPaleogenepaleotemperatureplanktonic taxaProtistasea waterstable isotopessymbiosisTertiaryurn:org.iodp:exp:120urnlargerWorkCitationcampaignurn:org.iodp:exp:171BurnlargerWorkCitationcampaignurn:org.iodp:exp:171B:site:1051urnlargerWorkCitationstudyurn:org.iodp:exp:171BurnlargerWorkCitationcampaignurn:org.iodp:exp:120:site:748urnlargerWorkCitationstudyurn:org.iodp:exp:120urnlargerWorkCitationcampaignEnglishgeoscientificInformation-76.212878.5854-58.262730.0311With GSA Data Repository Item 2013002