Planktonic lipids

Lipid material was extracted from the seawater and screen samples by coprecipitation with ferric hydroxide. Back in the laboratory, the precipitate was acidified and extracted with chloroform. After hydrolysis and methyla-tion of the extract with BF /MeOH, the relative proportions of fatty acids and alcohols in each of the samples was determined by GLC. A distribution of fatty acids centred on C,6 o [i.e., CH3(CH2)i4COOH, palmitic acid] t3rp-ical of planktonic lipids was found as illustrated in Fig. 5a for a typical surface sample. Garrett (1967c) noted that for some samples, the lipid extract was dominated by a high molecular weight material, apparently hydrocarbon, which was not surface active. 

Obvious sea slicks, where the film pressure exceeds —3 X 10 N m" and capillary waves are damped, eis well as surface scums and foam patches, all exhibit IR spectra with the same essential features as ambient films but often considerably enhanced. In addition, minor C—H bands at 2950, 2850 cm are often found (Fig. 6b). Thus the glycoprotein/proteoglycan material appears to dominate even in visible slicks, while the differences between slicks and ambient films are largely quantitative and not qualitative. It can be noted that such behaviour was predicted on the basis of film pressure/area behaviour in Section 2.2. Simple planktonic lipids do not appear to be an important constituent of natural sea slicks on the basis of the IR evidence, which agrees with the comparisons of microlayer analyses for these compounds with DOC and POC made in Section 3.4. 

This lipolysis index is usually strongly correlated with that of Weeks et al. However, it differs from theirs in that it takes into account all sources of hydrolysis products, polar and non-polar, since only hydrocarbons and sterols are missing in the denominator. In our Trinity Bay study, the lipolytic breakdown indices of net-tow samples were the same as in the sediment trap material suggesting plankton lipids were well preserved in traps. 

Different assemblages of organisms in the depositional environment could contribute to the acyclic isoprenoids e.g. pristane and phytane) and w-alkanes in the source rocks for these two oil families, including marine algae, archaebacteria, and land plants. For example, Schoell et al. (1992) showed that pristane (—26.7%o) and phytane (—26.1%c) in Miocene Monterey oil are isotopically enriched in compared to the C16-C22 n-alkanes (—27.6 0.2%o), apparently due to differences in source-rock organic matter input. They contend that pristane and phytane in the Monterey oil originated mainly from the phytol side chain of chlorophyll in marine phytoplankton and/or lipids in archaebacteria, while the n-alkanes originated from marine plankton lipids and land plant waxes. 

Ianora A, Boersma M, Casotti R, Fontana A, Harder J, Hoffmann F, Pavia H, Potin P, Poulet SA, Toth G (2006) New trends in marine chemical ecology. Estuaries Coasts 29 531-551 Irigoien X (2004) Some ideas about the role of lipids in the life cycle of Calarms finmarchicus. J Plankton Res 26 259-263... 

An inventory of known biomacromolecules is provided in Table 22.3. Many of these play essential metabolic roles in enabling growth and reproduction, such as the carbohydrates, lipids, proteins, and polynucleotides. Others are components of cell walls and exoskeletons. Some organisms, such as bacteria, plankton, plants, and lower invertebrates, synthesize biomolecules, called secondary metabolites, that are used to control ecological relationships, including predator/prey, host/symbiont, mating/spawning, and competition for food or space. 

Surface Water. Hargrave et al. (2000) calculated BAFs as the ratio of the compound tissue concentration [wet and lipid weight basis (ng/g)] to the concentration of the compound dissolved in seawater (ng/mL). Average log BAF values for lindane in ice algae and phyto-plankton collected from the Barrow Strait in the Canadian Archipelago were 5.68 and 5.49, respectively. 

Phytoplankton at the ocean surface maintain the fluidity of their cell membranes by altering their lipid (fat) composition when the temperature changes. When the ocean temperature is high, plankton synthesize relatively more 37 2 than 37 3.35... 

There is a strong interannual variation in the lipid concentration in the flesh of planktivorous fish such as anchovy, kilka and sprat, which is governed by the varying abundance of the plankton (Shulman, 1972b, 1996 Luts and Rogov, 1978 Luts, 1986). 

The study of the dynamics of fatness links the particular stock to the basic characteristics that influence the productivity of the ecosystem. It is much more difficult to define the relationship between fish fatness and the biomass of plankton. This is because current techniques for sampling deal solely with residual biomass, but not with the production generated by the most important components of the ecosystem. In addition, these techniques do not take into account factors such as elimination occurring at different trophic levels, so the lipid contents and numbers of fish - the final link in the chain - are the most reliable integrated characteristics of the condition of the ecosystem. Fatness of the fish also identifies rich feeding grounds, such as the north-western part of the Black Sea adjoining the mouth of the Danube. 

Lipid accumulation differs from somatic growth, since food plankton increases in abundance from the Mediterranean, via the Black to the Azov Sea, a situation that promotes the greatest accumulation of lipids in Azov fish. 

Brockerhoff, H., Yurkovski, M., Hoyle, R.J. and Ackman, R.G. (1964). Fatty acid distribution in lipids of marine plankton. Journal of the Fisheries Research Board of Canada 21,1379-1384. 

Farkas, T. and Herodek, S. (1964). The effect of environmental temperature on the fatty acid composition of crustacean plankton. Journal of Lipid Research 5,369-375. 

Yuneva, T.V. and Svetlichny, L.S. (1996). Hypoxia as a necessary factor in the accumulation of large amounts of lipid in planktonic copepods. In 6th International Conference on Copepoda, Oldenburg/Bremerhaven, Germany, July 29-August 3, p. 110 (Abstract). 

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