Lipids in Aquatic Ecosystems

Lipids in Aquatic Ecosystems provides a comprehensive summary of the most recent literature on the role of lipids in aquatic systems from many world experts. Essential fatty acids (EFAs), or omega-3 and omega-6 fatty acids as they are known in the popular press, have garnered considerable attention in the technical and popular literature during the last decade. Lipids are important energy storage molecules in most organisms. However, equally or even more important, specific lipids (e.g. EFAs) play critical roles in a wide range of physiological processes such as regulating the structural properties of cell membranes and serving as precursors to eicosanoid signaling molecules (i.e. prostaglandins, prostacyclins, the thromboxanes and the leukotrienes). It is well established the EFAs have important impacts on human health, and it is widely agreed that the classic "Western diet" is particularly imbalanced vis- -vis foods containing omega-3 versus omega-6 fatty acids. But beyond the specialist literature, it is not widely known that the most physiologically important long chain, polyunsaturated omega-3 fatty acids, i.e. eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are produced de novo principally by aquatic algae. Furthermore, within aquatic ecosystems these molecules may be synthesized from precursor fatty acid molecules and/or concentrated as they are conveyed to animals consumed by humans. For example, in salmonid fish DHA and EPA constitute 40% of total fatty acids, whereas in typical marine and freshwater phytoplankton EPA and DHA account for between 2% and 20% of total fatty acids. In humans, EPA and DHA play key roles in heart health, immune and inflammatory responses, visual acuity as well being major components of neurological tissues such as the brain and spinal cord. This realization has prompted great concern in the fisheries management community that the world's natural supply of EPA and DHA is being overexplo