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Aquatic agriculture in heavy-metal-polluted coastal areas faces major problems due to heavy metal transfer into aquatic organisms, leading to various unexpected changes in nutrition and primary and/or secondary metabolism. In the present study, the dual role of heavy metal copper (Cu) played in the metabolism of photosynthetic organism, the edible seaweed Sargassum fusiforme, was evaluated by characterization of biochemical and metabolic responses using both 1H NMR and GC-MS techniques under acute (47 µM, 1 day) and chronic stress (8 µM, 7 days). Consequently, photosynthesis may be seriously inhibited by acute Cu exposure, resulting in decreasing levels of carbohydrates, e.g., mannitol, the main products of photosynthesis. Ascorbate may play important roles in the antioxidant system, whose content was much more seriously decreased under acute than that under chronic Cu stress. Overall, these results showed differential toxicological responses on metabolite profiles of S. fusiforme subjected to acute and chronic Cu exposures that allowed assessment of impact of Cu on marine organisms.

The commercialization of biofuels produced from microalgae is in its infancy; therefore, many resource- management practices and production processes are still flexible. The purpose of this paper is to guide development of supply chains toward more environmentally sustainable practices. We review current and projected technologies and practices for autotrophic microalgae cultivation that promote environ- mental sustainability. We develop a framework that leverages these studies to propose better man- agement practices (BMPs) for water quality and quantity, biodiversity, or greenhouse gas emissions in concert with productivity and profitability considerations. Some proposed BMPs are linked to numerical environmental targets, such as percent reductions in nutrient loadings to streams, whereas others seek to avoid thresholds leading to adverse health or ecological effects. Still others involve using the best available technologies, developed iteratively through life-cycle and techno-economic analyses. Proposed BMPs for microalgae cultivation focus on water quality and quantity, as well as improving greenhouse gas (GHG) emissions to obtain advanced biofuel designation. BMPs must allow producers to meet produc- tivity and profitability targets, as well as environmental targets. These example BMPs characterize the state of science and engineering; thus, they will change over time. 

The focus of present-day aquaculture is typically monospecific animal culture. Even the development of “alternative” species for aquaculture usually refers to alternative species of fish or shellfish. However, although introducing another species of fish or shellfish may have short-term benefits, rarely does it balance energetically and ecologically in the long term. What is needed is appropriate proportions of different cocultured organisms, performing different processes throughout the day and seasonally. Other than in Asia, the fundamental role and the contribution of seaweeds in coastal waters have frequently been either ignored or misunderstood. Seaweeds are rarely factored into modeling equations of coastal systems. At a time when nutrification of coastal waters is becoming a pressing issue worldwide and the contribution of the inorganic output of aquaculture to regional nutrient loading is becoming more widely recognized, integrating seaweeds, which act as biological nutrient scrubbers, into fish or shellfish aquaculture is a promising, balanced-ecosystem approach. Integrating seaweeds into aquaculture systems provides bioremediation capability, mutual benefits to the co-cultured organisms, and economic diversification of the industry by producing another value-added marine crop. We discuss these concepts and illustrate the benefits of integrated multi-trophic aquaculture (IMTA) using projects that we are conducting in New England, USA, in which the culture of the red alga Porphyra (nori) is integrated with salmonid culture, and in the Maritime Provinces, Canada, in which open-water aquaculture of Chondrus crispus (Irish moss) is conducted in proximity to mussel and oyster aquaculture operations. The aquaculture industry recognizes its need to practice responsible aquaculture by moving in new directions, such as IMTA. This will require wise investment in research and development.

A PDF Power Point on "Big Island Abalone- yesterday, today, and tomorrow".