News
30.07.2020Publication of the paper "Alkenones as a temperature proxy in fin whale (Balaenoptera physalus) tissues"
PhD Lourdes Berdié from Gas chromatography – Applied mass spectrometry technology of the CCiTUB, has participated in the paper entitled "Alkenones as a temperature proxy in fin whale (Balaenoptera physalus) tissues" published in The Association for the Sciences of Limnology and Oceanography (ASLO) journal.
Alkenones are very resilient molecules produced by haptophyte organisms. These compounds have been widely used in the paleoceanography and paleoclimatology fields to estimate the water temperature in where these organisms grow.
In this study, alkenones have been analyzed for the first time in several whale tissues, expanding and adapting the paleoclimatic methodology in the field of the marine ecology. The research is part of Diego Rita doctoral thesis, directed by PhD Àlex Aguilar and PhD Xon Borrell from Department of Evolutionary Biology, Ecology and Environmental (BEECA) and from Biodiversity Research Institute (IRBio) of the University of Barcelona.
The Gas chromatography – Applied mass spectrometry Unit has participated in the research, accompanying and advising the process of setting up the method of alkenones determination in whale tissues: sample preparation, purification and interference detection and GC-MS analysis of the alkenones.
The alkenones analysis of the stomach content, internal and external fat, muscle and liver has allowed to determine the Uk37 unsaturation rate and estimate the temperature of the sea water where these mammal feed.
The article summary is:
| "Alkenones are a group of extremely resilient molecules produced by cosmopolitan haptophyte organisms. The unsaturation index (Uk'37) of di- vs. tri-unsaturated C37 alkenones C37:2·(C37:2+C37:3)−1) can be used to estimate the temperature of the water in which the alkenone-producing organisms grew. Alkenones have been widely used in paleoceanography, but they have received little attention in other fields. In this study, a method to detect alkenones in fin whale (Balaenoptera physalus) tissues is developed to adapt this technique to the marine ecology field. Five replicas of five tissues (stomach content, external blubber, internal blubber, muscle, and liver) were analyzed using gas chromatography coupled to mass spectrometry. Alkenones were present in both blubber tissues (66 ± 57 ng g−1 in external blubber 145 ± 89 ng g−1 in internal blubber), and in the stomach content ((3126 ± 2643 ng g−1). The calculated Uk'37 index was very similar in the three tissues: 0.54 ± 0.03 in the external blubber, 0.55 ± 0.08 in the internal blubber, and 0.71 ± 0.06 in the stomach content. These indexes are equivalent to a sea surface temperature estimates of 17.79 ± 0.68 C in the external blubber, 17.84 ± 1.84 C in the internal blubber, and 21.07 ± 1.23 C in the stomach content, which are very similar to the expected temperature for the region. The results of the current study indicate that alkenones biodilute in the trophic web, which could hinder the analyses of alkenones in species with a high trophic level. However, it is shown that alkenones can be detected in fin whale tissues and can be used to approximate the environmental water temperatura where these animals feed." |
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