Lipids are natural molecules soluble in organic solvents, including molecules containing fatty acid moieties and a range of secondary metabolites that are derived from fatty acids. Examples include triglycerides, phospholipids, sterols and many hormones.  They combine with carbohydrates and proteins to form the majority of all plant and animal cells – they are particularly important in cell membranes where they may have both structural and functional roles, but lipids are also important energy stores for many classes of organism.

Omega-3 fatty acids, which are commonly found in fish oils, have received a lot of attention, as research has suggested that an intake of this fatty acid can reduce the risk of heart disease. There is also some evidence that dietary manipulation of polyunsaturated fatty acids can affect brain function leading to improvements for several disorders.

The fatty acids and other lipids are essential to every living organism, they play vital roles in membrane composition, energy storage and the regulation of metabolic processes.

Here at SAMS we use lipids to investigate a number of marine issues:  

1. Lipids in sediments

Fatty acids are a very minor component of the organic matter in sediments, but can provide information on the carbon sources in the overlying ocean, trophic linkages and diagenetic processes.  One common form of analysis looks at changes in the fatty acids during the seasonal cycle.  Biomarkers, compounds whose origin can be easily identified, have been identified for different species of phytoplankton, for bacteria and for terrestrial carbon sources.  Looking for these fatty acid signatures in the sediment can help identify the main carbon sources.

2. Lipids as trophic indicators

Biomarkers can be used to identify diet composition by comparing the fatty acid profile of the consumer with potential dietary constituents.  We have used this technique to investigate, amongst others, diets of the caprellid, Caprella mutica, and the cold water coral, Lophelia pertusa.  Fatty acids can also be used to investigate seasonal changes in the profile which can result from changes in the diet or changes in the reproductive state of the organism.

3. Alkenones

Alkenone analysis is a very useful tool for looking at long-term climatic changes.  Alkenones are long chain unsaturated ketones which are almost exclusively produced by marine algae, especially the coccolithophore, Emiliania huxleyi.  These algae have the ability to synthesise alkenones whose degree of unsaturation varies with the surrounding water temperature.  When these algae die they sink to the seabed and become integrated into the sediment.  By assessing the ratios of these di- and tri-unsaturated alkenones we can calculate the water temperature in which they grew.  By combining alkenone analysis with chronology derived by radionucleides we can build up a picture of historic climate change.

Past work:

• Using lipids as indicators of organic matter origin around a fish farm in the Gulf of Eilat, Israel
• Using sedimentary lipids to consider differences in organic matter flux to 4 stations of similar depth (about 1400m) on a transect between the Norwegian and Svalbard margins
• Using sedimentary lipids to consider differences in organic matter supply along a latitudinal transect from Svalbard west into deep water (2500m)
• Using lipids to distinguish differences of location, depth and diet in the cold water coral, Lophelia pertusa
• Influence of diet on the lipid composition of 2 species of sea urchin (Paracentrotus lividus and Psammechinus miliaris)
• Using lipids to distinguish differences of location and diet in the caprellid, Caprella mutica
• Influence of diet on the lipid composition of 2 species of sea urchin larvae (Paracentrotus lividus and Psammechinus miliaris)
• Influence of diet on the lipid composition of the abalone, Haliotis tuberculata

Publications:

 
Cook, E.J. & M.S. Kelly (in prep).  Effect of enriched macroalgae, Palmaria palmata on the feeding and growth of the European abalone, Haliotis tuberculata

Cook, E.J., Ashton, G., Shucksmith, R. (in prep).  Fatty acid composition of the invasive caprellid, Caprella mutica: Trophic implications.

Gutierrez, T., Mulloy, B., Bavington, C., Black, K., Green, D.H.  (in revision)  Partial purification and chemical characterization of a glycoprotein (putative hydrocolloid) emulsifier produced by a marine bacterium Antarobacter.  Appl. Microbiol. Biotechnol.

Gutierrez, T., Mulloy, B., Black, K., Green, D.H.  (in press)  Glyocoprotein emulsifiers from two marine Halomonas species: chemical and physical characterisation.  J. Appl. Microbiol.

Liu, H., Kelly, M.S., Cook, E.J., Black, K.D., Orr, H., Zhu, J.X., Dong, S.L.  (2007)  The effect of diet type on the growth and fatty acid profile of sea urchin larvae I Paracentrotus lividus (Lamarck, 1816) (Echinodermata).  Aquaculture 264: 247-262

Liu, H., Kelly, M.S., Cook, E.J., Black, K.D., Orr, H., Zhu, J.X., Dong, S.L.  (2007)  The effect of diet type on the growth and fatty acid profile of sea urchin larvae II  Psammechinus miliaris (Gmelin).  Aquaculture 264: 263-278

Obajimi, O., Black, K. D., Macdonald, D. J., Boyle, R. M., Glen, I. and Ross, B. M. (2005) Differential effects of eicosapentaenoic and docosahexaenoic acids upon oxidant-stimulated release and uptake of arachidonic acid in human lymphoma U937 cells. Pharmacology Research 52: 183-191.

Hughes, A.D., Catarino, A.I., Kelly, M.S., Barnes, D.K.A., Black, K.D.  (2005)  Gonad fatty acids and trophic interactions of the echinoid Pasmmechinus miliaris.  Mar. Ecol. Prog. Ser. 305: 101-111

Hughes, A.D., Kelly, M.S., Barnes, D.K.A., Catarino, A.I., Black, K.D.  (2005)  The dual functions of sea urchin gonads are reflected in the temporal variations of their biochemistry.  Mar. Biol. 148(4): 789-798

McKenzie, J.D., Black, K.D., Kelly, M.S., Newton, L.C., Handley, L.L., Scrimgeour, C.M., Raven, J.A., Henderson, R.J.  (2000)  Comparisons of fatty acid and stable isotope ratios in symbiotic and non-symbiotic brittlestars from Oban Bay, Scotland.  J. Mar. Biol. Assoc. U.K. 80(2): 311-320

Cook, E.J., Bell, M.V., Black, K.D., Kelly, M.S. (2000)  Fatty acid compositions of gonadal materials and diets of the sea urchin, Psammechinus miliaris:  trophic and nutritional implications.  J. Exp. Mar Biol. Ecol. 255(2): 261-274

Carrie, R.H., Mitchell, L., Black, K.D.  (1998)  Fatty acids in surface sediments at the Hebridean shelf edge, west of Scotland.  Org. Geochem. 29(5-7):1583-1593