Singh_2011.tab (4.58 kB)

(Table S1) Age determination of sediment cores SK99_17 and MD76-131

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posted on 16.07.2019 by Arun Deo Singh, Simon J A Jung, Kate Darling, Raja S Ganeshram, Tara S Ivanochko, Dick Kroon
Productivity in the Arabian Sea is one of the highest in the world. It is controlled by seasonally reversing monsoonal wind-driven upwelling of nutrient-rich deeper waters which fuel phytoplankton growth. The detailed history of upwelling-induced productivity in the eastern Arabian Sea is unknown. Here we present paleoproductivity records from a composite sediment core at the millennial scale during the last 80 kyr B.P. These records are based on relative abundance counts of planktonic foraminifera and organic carbon contents, which are shown to mainly vary in concert. The eastern Arabian Sea upwelling-induced productivity was higher in the glacial period than in the Holocene, but it fell repeatedly on millennial timescales. These productivity declines occurred during cold events in the North Atlantic region, with the most pronounced changes prevailing during the Heinrich events. Hence, seasonal monsoon winds that drive upwelling-induced productivity in the east were weak when the North Atlantic was cold. These weak winds resulted in stratification of the water column, comparable to today's Arabian Sea stratification in the intermonsoonal period. Combining the new eastern with published western Arabian Sea results shows that the entire biological factory was severely diminished during the North Atlantic Heinrich events, and the seasonal productivity change in the Arabian Sea monsoon system was reduced with year-round low productivity. Ages of MD76-131 adopted from Ivanochkov (2005).

History

Year

2011

Size

102 data points

Coverage

* Median Latitude: 15.39 * Median Longitude: 72.767485 * South-bound Latitude: 15.25 * West-bound Longitude: 72.5683 * North-bound Latitude: 15.53 * East-bound Longitude: 72.96667 * Date/Time Start: 1976-01-01T00:00:00 * Date/Time End: 1976-01-01T00:00:00 * Minimum DEPTH, sediment/rock: 0.015m * Maximum DEPTH, sediment/rock: 0.015m

Event(s)

MD76-131 * Latitude: 15.53 * Longitude: 72.5683 * Date/Time: 1976-01-01T00:00:00 * Elevation: -1230.0 * Recovery9.5 m * Location: Indian Ocean * Campaign: MD10 (OSIRIS II) * Basis: Marion Dufresne * Device: Piston corer (PC) SK99_17 SK17 * Latitude: 15.25 * Longitude: 72.96667 * Elevation: -640.0 * Location: Indian Ocean * Device: Gravity corer (GC)

Related to

Ivanochko, Tara S (2005): Sub-orbital variations in the intensity of the Arabian Sea monsoon. Ph.D. thesis, University of Edinburgh, Edinburgh, U.K., 230 pp,

Comment

Ages of MD76-131 adopted from Ivanochkov (2005).

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