Crustacean zooplankton fatty acid composition

Abstract

Fatty acids (FA) are among the most important molecules transferred across the plant–animal interface in aquatic food webs. Particular classes of FA, such as the n-3 highly unsaturated fatty acids (HUFA), are important somatic growth limiting compounds for herbivorous zooplankton (Müller-Navarra 1995a; Müller-Navarra et al. 2000; Ravet et al. 2003). These molecules are also critical for the growth, disease resistance, and general well being of juvenile fish (Adams 1999; Olsen 1999; Sargent et al. 1999). Thus, knowing how nutritionally important FA are conveyed through food webs has important implications for understanding economically important fisheries. A very substantial literature shows these same molecules have a wide range of positive impacts on human health (Simopoulos 1999; Arts et al. 2001). Specific FA may also help interpret trophic relations in aquatic systems (Dalsgaard et al. 2003), as the group specific FA composition of primary producers varies greatly (Volkman et al. 1989; Ahlgren et al. 1992). Therefore, it is important to understand how much the FA composition of zooplankton is determined by taxonomic affiliation, changed by diet, and modified by starvation or temperature. It is also essential to know whether zooplankton maintain a semiconstant FA profile relative to their diets or, alternatively, bioconvert some FA into other FA molecules. This review will summarize the published information on how these factors regulate the FA composition of freshwater and marine zooplankton.