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Seasonality and habitat controls on planktonic foraminifera - Compound specific δD analysis of alkenones and particulate organic matter. Stefan Schouten, Geert Jan Brummer (PI’s) Marcel van der Meer, Ulrike Fallet (project members). WHAT ?.
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Seasonality and habitat controls on planktonic foraminifera - Compound specific δD analysis of alkenones and particulate organic matter Stefan Schouten, Geert Jan Brummer (PI’s) Marcel van der Meer, Ulrike Fallet (project members) NIOZ is part of the Netherlands Organisation for Scientific Research (NWO)
WHAT ? 1. Validate the relationships between the δD of organic compounds and the δD in the water column, in contrasting natural salinity-temperature fields. 2. In parallel, develop empirical relationships for Mg/Ca and δ18O-δ13C incorporation into foraminiferal carbonates and determine vital effects during calcification in their changing depth habitat across salinity-temperature fields, 3. Determine and model the differential response of salinity proxies in terms of the changing stratification and seasonal flux of δD, Mg/Ca and δ18O-δ13C from upper ocean, as carried in the organic- and bio-inorganic phases arriving on the ocean floor.
O Results for delta D
Problem dD measurements • Machine: • Long time probles with stability and reproducibility • Performance checked with “Schimmelman” standards • Measure when difference <5 per mill on average • Coinjeced standards to check performance (<3 per mill) • Amounts: • 5x higher than 13C, 20x higher than regular GC
Future work dD algal biomarkers • Cultures: • Light-controlled growth experiments of E. huxleyi • (A. Benthien) • Dinoflagelllate cultured to examine dinosterol fractionation • (Marcel van der Meer) • Diatom cultured to examine alkanediol fractionation • (in progress) • POM/sediments: • Low abundance, difficult to analyse for hydrogen isotopes
Paleosalt NIOZ/VU: decoupling temperature and salinity effects in biogenic carbonates Red Sea Somalia Mozambique Channel
Paleosalt NIOZ/VUA: decoupling temperature and salinity effects in biogenic carbonates: d18O-Mg • Embedded in LOCO-CLIVAR (moorings), throughflow in the Mozambique Channel: 2003-2008 • affiliated with SINDOCOM (corals) • affiliated with LOCO-CLIVAR (moorings), meltwater in the Irminger Sea: 2003-2008
Paleosalt: • Red Sea (strongly inverse T-S gradients) • 36.5 to 41‰, 31 to 19°C in spring (evaporitic, single watermass) • plankton tows (surface, depth-stratified) • Somalia margin (constant S, strong T gradient) • 16 to 29°C in summer upwelling • plankton tows, time-series traps, cores • Mozambique Channel • 24 to 30°C, 34.6 to 35.1‰ seasonally • time-series traps (5 years), cores • affiliated with coral programme (SINDOCOM) and speleothems
Red Sea surface sediments (University of Tubingen) 37:2
Paleosalt: Mozambique Channel summer summer summer winter winter Surface temperature Seasonal amplitude 7 °C (24 - 31 °C) summer winter summer Surface salinity Seasonal amplitude 0.5 ‰ (34.7 - 35.2 ‰)