Gerald Ganssen

Stable isotopic measurement on planktonic foraminifera of vertical plankton haul samples GIK15666-8, off NW Africa (Table 1d)

Stable isotopic measurement on planktonic foraminifera of vertical plankton haul samples GIK15658-2, off NW Africa (Table 1d)

Stable isotopic measurements on planktonic foraminifera of plankton haul samples off Northwest Africa (Table 1d)

Hydrography and plankton abundance of vertical plankton haul profile GIK15679-2, off NW Africa (Table 1c)

Hydrography and plankton abundance of vertical plankton haul profile GIK15678-3, off NW Africa (Table 1c)

Stable isotopes on recent foraminifera from surface sediments off northwest Africa

Isotopic analysis of foraminifera shells: Interference from chemical treatment

Palaeogeography, Palaeoclimatology, Palaeoecology, 1981

ABSTRACT Foraminifera shells were soaked in solutions of formalin, ethanol, tetrachlorethylene an... more ABSTRACT Foraminifera shells were soaked in solutions of formalin, ethanol, tetrachlorethylene and hydrogen peroxide; also, crushed Solnhofen Limestone was exposed to formalin. Formalin treatment caused a significant change in the results of stable isotope analysis. The effect is interpreted as a result of partial dissolution. Soaking other than those with formalin did not affect isotopic analysis.

Ocean stratification versus vertical mixing in the north Atlantic Ocean during the last glacial

The fluctuating cover of sea ice and melting glaciers in the North Atlantic region during the mos... more The fluctuating cover of sea ice and melting glaciers in the North Atlantic region during the most recent three Marine Isotopic Stages (MIS) has been well documented. The consequences of this, either seasonal or perennial ice cover, on oceanographic conditions (i.e. mixing or stratification) has yet to be fully unravelled. Within the scope of the Darwin Center project Sensing Seasonality we shed light on the effects of melting sea-ice versus land-ice on the ocean conditions during short term (i.e. Heinrich Events) and long term (LGM) cold events. Core T88-3P is strategically located just north of the IRD belt (56°43.8N; 27°79.7W; 2819m water depth). The stable isotope data of different species of planktonic and benthic foraminifera reflect the degree of water mass stratification. As we apply single specimen foraminiferal isotope analysis we are able to extract the full seasonal range (i.e. annual mean, minima and maxima) of sea surface temperatures. Combining stable isotopes with fa...

Southwest Pacific modulation of abrupt climate change during the Antarctic Cold Reversal–Younger Dryas

Palaeogeography, Palaeoclimatology, Palaeoecology, 2008

The giant piston core, MD97-2121 (2314-m water depth), collected north of the Subtropical Front, ... more

Phenotypic variation of Globorotalia scitula (foraminiferida) as a response to Pleistocene climatic fluctuations

Marine Geology, 1987

... The Netherlands PHENOTYPIC VARIATION OF GLOBOROTALIA SClTULA (FORAMINIFERIDA) AS A RESPONSE T... more

Shells weights from sediment core 905B

Proxies of modern Indian Ocean pelagic carbonates, budget and preservation potential

Planktonic foraminiferal Mg/Ca ratios from the water column and their implications for paleothermometry

Abrupt Climate Change In N-africa: The Asynchronous Termination of The African Humid Period

NE-Africa and Arabia are foci for early prehistoric civilisations and these regions are controlle... more NE-Africa and Arabia are foci for early prehistoric civilisations and these regions are controlled by the Asian and African monsoon that are among the most fragile parts of Earth's climate. General links between climate and human prehistoric evo- lution have been proposed but there are few climate data from these regions with a decadal/centennial time resolution. Consequently it is difficult to unambiguously re- late human socio-cultural evolution to climate change. Based on the Sr-Nd isotope records of the lithic sediment fraction from sediment Core 905 (NW Arabian Sea off Somalia) we deduce in detail the Holocene weathering history of NE Africa. We show that the Early Holocene (10-6 ka) was generally more humid than today (African hu- mid period - AHP) but that there were three centennial scale arid-humid oscillations each punctuated by even shorter events. A dramatic change towards dryer conditions between 6 and 3.8 ka BP marks the end of the AHP and dry conditions prevail ov...

Evaluating the role of the biological pump in the northeast atlantic through paleo primary productivity reconstruction

Studies in Environmental Science, 1995

... Paleo primary productivity was derived from biogenic carbonate accumulation rates according t... more

Northern Indian Ocean upwelling cells and the stable isotope composition of living planktonic foraminifers

Deep Sea Research Part A. Oceanographic Research Papers, 1989

... Northern Indian Ocean upwelling cells and the stable isotope composition of living planktonic... more

Mg/Ca palaeothermometry of foramiferal calcite and Cenozoic ocean temperatures

Variability of Shell Mass, delta 18O and Mg/Ca in Planktonic Foraminifera: From Production to Preservation

Mg/Ca in planktonic foraminifera tests is now well established as a temperature proxy for surface... more Mg/Ca in planktonic foraminifera tests is now well established as a temperature proxy for surface and near-surface waters. Yet work remains to be carried out to define the post-depositional processes affecting foraminiferal Mg/Ca after water-column production. The advantage of Mg/Ca over other paleotemperature proxies is that it can be coupled with delta 18O measured on the same foraminiferal sample so

Coupled sea surface temperature-seawater delta O-18 reconstructions in the Arabian Sea at the millennial scale for the last 35 ka

Species-specific coccolith calcite chemistry response to monsoonal upwelling (northwestern Indian Ocean)

The chemistry of coccoliths serves both as a record of changes in the chemistry of the ocean and ... more The chemistry of coccoliths serves both as a record of changes in the chemistry of the ocean and as a record of environmental and biological conditions like temperature and productivity. It documents different information than that of foraminiferal carbonate because coccolithophorids, unlike foraminifers, are primary producers. Recently, a breakthrough in the separation of monospecific coccolith assemblages enabled detailed work on stable isotope composition and minor and trace elements of individual coccolith species in sediment trap and sediment samples. Culture studies indicate different nonequilibrium effects in the oxygen isotope fractionations in different species of coccolithophorids. Interest in nonequilibrium effects is also increasing as new studies reveal that these effects may provide useful new indicators for paleoceanographic studies. In the case of coccolithophorids, nonequilibrium effects appear to reflect changing ecological and physiological responses of the organi...

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Papers by Gerald Ganssen