Alkenone Paleothermometry
Alkenone Paleothermometry - Related Videos
10:10
An Overview of Alkenone Biomarker Analysis for Paleothermometry
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2023
Source: Laboratory of Jeff Salacup - University of Massachusetts Amherst Throughout this series of videos, natural samples were extracted and purified in search of organic compounds, called biomarkers, that can relate information on climates and environments of the past. One of the samples analyzed was sediment. Sediments accumulate over geologic time in basins, depressions in the Earth into which sediment flows through the action of fluid (water or air), movement, and gravity. Two main types...
07:52
Removal of Branched and Cyclic Compounds by Urea Adduction for Uk'37 Paleothermometry
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2023
Source: Laboratory of Jeff Salacup - University of Massachusetts Amherst As mentioned in previous videos, the product of an organic solvent extraction, a total lipid extract (TLE), is often a complex mixture of hundreds, if not thousands, of different compounds. The researcher is often only interested in a handful of compounds. In the case of our two organic paleothermometers (Uk'37 and MBT/CBT), the interest is in only 6 compounds (2 alkenones and 4 isoprenoidal glycerol dialkyl glycerol...
08:28
Conversion of Fatty Acid Methyl Esters by Saponification for Uk'37 Paleothermometry
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2023
Source: Laboratory of Jeff Salacup - University of Massachusetts Amherst The product of an organic solvent extraction, a total lipid extract (TLE), is often a complex mixture of hundreds, if not thousands, of different compounds. The researcher is often only interested in a handful of compounds or, if interested in many, may need to remove unwanted constituents that are"in the way" or co-eluting. For example, the concentrations of individual compounds in a sample are often determined on a gas...
09:10
Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass
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Cited by 8 •
2016
Detailed methods are presented for the production of biodiesel along with the co-isolation of alkenones as valuable coproducts from commercial Isochrysis microalgae.
09:18
Purification of a Total Lipid Extract with Column Chromatography
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2023
Source: Laboratory of Jeff Salacup - University of Massachusetts Amherst The product of an organic solvent extraction, a total lipid extract (TLE), is often a complex mixture of hundreds, if not thousands, of different compounds. The researcher is often only interested in a handful of compounds. The compounds of interest may belong to one of several classes of compounds, such as alkanes, ketones, alcohols, or acids (Figure 1), and it may be useful to remove the compound classes to which it does...
FAQs
Haptophyte algae adjust the degree of unsaturation in their long-chain alkenones in a predictable relationship with the temperature at which they grow. Warmer or cooler conditions therefore leave different molecular patterns in the alkenone mixture. Measuring these patterns allows scientists to translate preserved biochemical signals into estimates of past sea-surface temperature rather than relying on direct instrumental observations.
The UK′37 index summarizes the relative unsaturation pattern of alkenones preserved in marine sediment. Scientists compare that measured index with calibrations established from modern temperature records, converting the molecular value into an estimated sea-surface temperature. Its importance lies in linking a chemical measurement in a sediment sample to a temperature interpretation grounded in observations of the modern ocean.
Alkenones can persist after burial in marine sediments, allowing their original environmental signal to remain available after deposition. As sediment accumulates, deeper material generally represents older conditions, so sediment cores preserve a chronological sequence of molecular measurements. This combination of persistence and layered deposition enables scientists to examine ocean temperature and environmental change across geological timescales.
A typical interpretation begins with a sediment core that represents a sequence through time. Scientists measure the preserved alkenones in selected sediment material, determine the UK′37 index, and apply a calibration based on modern temperature records. The resulting temperature estimates can then be arranged according to the core’s chronology to reconstruct changing sea-surface conditions.
Temperature estimates derived from sediment archives can reveal patterns of past ocean warming, cooling, and climate variability. Because the record may extend across geological timescales, researchers can compare long-term changes with climate model results and investigate how ocean systems responded under different environmental conditions. These reconstructions provide historical context that direct modern measurements cannot supply.
By reconstructing earlier sea-surface temperatures, the method provides environmental context for examining marine ecosystem responses to changing ocean conditions. Researchers can relate temperature histories to broader patterns of climate variability and to changes associated with natural or human-driven forces. This helps frame present-day ocean change within a longer record of interactions between climate and marine systems.