Planktic foraminiferal sieve size specific d13C and d18O values and maximum test diameter from ODP sites 171-1051 and 120-748, supplement to: Edgar, Kirsty M; Bohaty, Steven M; Gibbs, Samantha J; Sexton, Philip F; Norris, Richard D; Wilson, Paul A (2013): Symbiont 'bleaching' in planktic foraminifera during the Middle Eocene Climatic Optimum. Geology, 41(1), 15-18


Many 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 (d13C) was temporarily reduced for ~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 d18O values and reduction in test size-d13C 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.

Metadata Access
Creator Wilson, Paul A;Gibbs, Samantha J;Edgar, Kirsty M;Norris, Richard D;Bohaty, Steven M;Sexton, Philip F
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2013
Rights Creative Commons Attribution 3.0 Unported (CC-BY)
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Discipline Earth System Research
Spatial Coverage (58S-30N,76W-79E)
Temporal Point 1988-03-14T11:59:59Z