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Net primary production (NPP) is influenced by disturbance-driven fluctuations in foliar standing crop (FSC) and resource-driven fluctuations in rates of recruitment and growth, yet most studies of NPP have focused primarily on factors influencing growth. We quantified NPP, FSC, recruitment, and growth rate for the giant kelp, Macrocystis pyrifera, at three kelp forests in southern California, USA, over a 54-month period and determined the relative roles of FSC, recruitment, and growth rate in contributing to variation in annual NPP. Net primary production averaged between 0.42 and 2.38 kg dry massm2 yr1 at the three sites. The initial FSC present at the beginning of the growth year and the recruitment of new plants during the year explained 63% and 21% of the interannual variation observed in NPP, respectively. The previous year’s NPP and disturbance from waves collectively accounted for 80% of the interannual variation in initial FSC. No correlation was found between annual growth rate (i.e., the amount of new kelp mass produced per unit of existing kelp mass) and annual NPP (i.e., the amount of new kelp mass produced per unit area of ocean bottom), largely because annual growth rate was consistent compared to initial FSC and recruitment, which fluctuated greatly among years and sites. Although growth rate was a poor predictor of variation in annual NPP, it was principally responsible for the high mean values observed for NPP by Macrocystis. These high mean values reflected rapid growth (average of ;2% per day) of a relatively small standing crop (maximum annual mean¼444 g dry mass/m2 ) that replaced itself approximately seven times per year. Disturbance-driven variability in FSC may be generally important in explaining variation in NPP, yet it is rarely examined because cycles of disturbance and recovery occur over timescales of decades or more in many systems. Considerable insight into how variation in FSC drives variation in NPP may be gained by studying systems such as giant kelp forests that are characterized by frequent disturbance and rapid rates of growth and recruitment.

Final Report of Biomarine London Summit 24-25 Oct. 2012

Talks Include:

- Debate Marine Bio-Resources: A Bright Future

- Think Tank Algae and Aquafeed

- Think Tank Marine Biotech for Health

- Think Tank Nutraceuticals

- Think Tank Aquaculture

- Think Tank Microalgae & Nutrition

- Think Tank Marine Biotechs for Environment

- Aquaculture Debate

The shortage of fossil fuels is actually a major economic issue in the context of increasing energy demand. Renewableenergies are thus gaining in importance. For instance, microalgae-based fuels are viewed as an alternative. Microalgae aremicroscopic unicellular plants, which typically grow in marine and freshwater environments. They are fast growing, havehigh photosynthetic efciency, and have relatively small land requirement and water consumption in comparison with con-ventional land crops biofuels. Nonetheless, selling biofuels is still limited by high cost. Here, we review biofuel productionfrom microalgae, including cultivation, harvesting, drying, extraction and conversion of microalgal lipids. Cost issues maybe solved by upstream and downstream measures: (1) upstream measures, in which highly productive strains are obtainedby strain selection, genetic engineering and metabolic engineering, and (2) downstream measures, in which high biofuelsyields are obtained by enhancing the cellular lipid content and by advanced conversion of microalgal biomass to biofuels.Maximum biomass and high biofuels production can be achieved by two-stage culture strategies, which is a win–win approachbecause it solves the conficts between cell growth and biomass accumulation.

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.