Last glacial-interglacial productivity and associated changes in the eastern Arabian Sea
| Autor: | S.R. Kurtarkar, Rajeev Saraswat, Andreas Mackensen, David W. Lea, D. K. Naik |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010504 meteorology & atmospheric sciences
biology Paleontology Last Glacial Maximum Globigerina bulloides 010502 geochemistry & geophysics Oceanography biology.organism_classification 01 natural sciences 13. Climate action Interglacial Deglaciation 14. Life underwater Glacial period Stadial Ecology Evolution Behavior and Systematics Geology Holocene Globigerinoides 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Palaeogeography, Palaeoclimatology, Palaeoecology. 483:147-156 |
| ISSN: | 0031-0182 |
| DOI: | 10.1016/j.palaeo.2016.07.014 |
| Popis: | We reconstruct paleo-productivity and bottom water oxygenation changes during the past 32 ka, from the southeastern Arabian Sea, using absolute abundance of planktic foraminifera, relative abundance of Globigerina bulloides , angular asymmetrical benthic foraminifera (AABF), measurements of total organic carbon (C org ), %CaCO 3 , and Globigerinoides ruber δ 18 O and δ 13 C. The faunal and geochemical proxies suggest that productivity in the southeastern Arabian Sea was high during MIS 3. A distinct decrease in productivity is inferred during the last glacial maximum (19–23 ka) (LGM). Bottom water was well oxygenated during MIS3, only to become oxygen-depleted during the LGM. Productivity decreased abruptly during Heinrich Stadial 1 (HS-1), but the response to Heinrich Stadial 2 (HS-2) was different. Low productivity during the early deglaciation is also synchronous with an increase in ice-volume corrected δ 18 O (δ 18 O sw-ivc ), a salinity proxy, between 18.9 (18.3–18.9) ka BP and 15.9 (15.0–16.3) ka BP, and a concomitant decrease in δ 13 C between 18.2 (17.5–18.7) ka BP and 16.4 (15.3–16.7) ka BP. These patterns suggest that the global δ 13 C minimum event during the last deglaciation was associated with the weak monsoon interval during HS-1 and a drop in productivity in tropical regions. A progressive increase in productivity is observed throughout the Holocene, with a distinct jump at 5.4 (3.8–6.3) ka BP. We infer that although productivity was higher in the eastern Arabian Sea during most of the last glacial interval, the overall resultant carbon sequestration was confined only to a restricted zone and not large enough to substantially alter atmospheric CO 2 . |
| Databáze: | OpenAIRE |
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