Grant: Discovery Grants Program - Individual

This study is a continuation of our ongoing program of research to investigate the importance of lipids in marine organisms and the cycling of these carbon-rich compounds in cold ocean ecosystems. Objective 1: to compare lipid production, transport and fate in very different fjords at the same latitude: Bonne Bay, Newfoundland and Saanich Inlet, Vancouver Island. In studying these two seasonally highly productive areas we will test hypotheses concerning polyunsaturated fatty acid (PUFA) synthesis and membrane fluidity in relation to temperature, and PUFA oxidation in relation to oxygen concentrations. These studies are timely given continuing fishery problems, interest in new fishery species, and increasing aquaculture on both coasts. Objective 2: to set up feeding experiments focussing on biomarker and nutritional lipids including omega-3 and omega-6 PUFAs. In tandem with our first objective, we will investigate short food chains leading to scallops, echinoderms and cod. Such a unique and ambitious study is possible at the Ocean Sciences Centre where we have each of the components in culture and where we have the instrumentation to perform these analyses. These experiments are important for using biomarkers to identify food web sources, pathways and sinks and for determining the extent of conservation and modification of critical essential fatty acids. Objective 3: to investigate the effects of high levels of PUFA on oxidative status and membrane fluidity in animals from our field and lab studies. We will look at oxidation products of PUFA and we will determine fluidity of cell membranes. In the marine literature the oxidative instability of PUFA and their importance in maintaining membrane fluidity have often been stated: this will be among the few attempts at actually determining if this is true. The oxidation data will help explain losses in food webs and why some lipids have been shown to be toxic. This is very important for protecting against deleterious effects of lipids in aquaculture and in the study of harmful algal blooms. The combination of the fluidity, food web and oxidation work is critical to the nutritional management of finfish and bivalve broodstock and larvae in Canadian aquaculture.