alkenones

[′al·kə‚nōnz]

(geology)

Long-chain (37-39 carbon atoms) di-, tri-, and tetraunsaturated methyl and ethyl ketones produced by certain phytoplankton (coccolithophorids), which biosynthetically control the degree of unsaturation (number of carbon-carbon double bonds) in response to the water temperature; the survival of this temperature signal in marine sediment sequences provides a temporal record of sea surface temperatures that reflect past climates.

References in periodicals archive ?

Eastern tropical Pacific hydrologic changes during the past 27,000 years from D/H ratios in alkenones.

Paleoxigenacion y paleoproductividad en el golfo de Panama durante el holoceno tardio

Further evaluation of long-chain alkenones as indicators of paleoceanographic conditions.

Cocolitoforos en sedimentos marinos frente a la entrada occidental del Estrecho de Magallanes (53[grados]S) revelan cambios en la productividad durante los ultimos 30.000 anos

To reconstruct the salinity, the WHOI team analyzed sediments containing highly resistant organic compounds called alkenones, which are uniquely produced by Emiliania huxleyi-the same photosynthetic organism oceanographers study to determine past sea surface temperatures.

Black Sea 'goldmine of ancient genetic data'

Researchers analysed marine sediment collected by drilling and measured alkenones - organic compounds produced by phytoplankton.

Another piece of climate puzzle solved by scientists

Many papers discus the controlling mechanisms that may have forced major climate change, such as geographical and oceanographic changes during the Late Ordovician or changing ocean gateways in the Cenozoic, while others discuss biological and chemical proxies that can be used to track ancient climate change, such as the use of Ca/Mg ratio of foraminifer tests or alkenones from surface- dwelling marine-algae.

Deep-time perspectives on climate change; marrying the signal from computer models and biological proxies