The response of calcifying plankton to climate change in the Pliocene
As a result of anthropogenic <i>p</i>CO<sub>2</sub> increases, future oceans are growing warmer and lower in pH and oxygen, conditions that are likely to impact planktic communities. Past intervals of elevated and changing <i>p</i>CO<sub>2</sub> and...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2013-09-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/10/6131/2013/bg-10-6131-2013.pdf |
| Summary: | As a result of anthropogenic <i>p</i>CO<sub>2</sub> increases, future oceans are growing warmer and lower in pH and oxygen, conditions that are likely to impact planktic communities. Past intervals of elevated and changing <i>p</i>CO<sub>2</sub> and temperatures can offer a glimpse into the response of marine calcifying plankton to changes in surface oceans under conditions similar to those projected for the future. Here we present new records of planktic foraminiferal and coccolith calcification (weight and size) from Deep Sea Drilling Project Site 607 (mid-North Atlantic) and Ocean Drilling Program Site 999 (Caribbean Sea) from the Pliocene, the last time that <i>p</i>CO<sub>2</sub> was similar to today, and extending through a global cooling event into the intensification of Northern Hemisphere glaciation (3.3 to 2.6 million years ago). Test weights of both surface-dwelling Foraminifera <i>Globigerina bulloides</i> and thermocline-dwelling Foraminifera <i>Globorotalia puncticulata</i> vary with a potential link to regional temperature variation in the North Atlantic, whereas in the tropics <i>Globigerinoides ruber</i> test weight remains stable. In contrast, reticulofenestrid coccoliths show a narrowing size range and a decline in the largest lith diameters over this interval. Our results suggest no major changes in plankton calcite production during the high <i>p</i>CO<sub>2</sub> Pliocene or during the transition into an icehouse world. |
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| ISSN: | 1726-4170 1726-4189 |