78 research outputs found

    Harmful Algal Blooms. A scientific summary for policy makers

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    What is a Harmful Algal Bloom (HAB)? Photosynthetic algae support healthy aquatic ecosystems by forming the base of the food web, fixing carbon and producing oxygen. Under certain circumstances, some species can form high-biomass and/or toxic proliferations of cells (or “blooms”), thereby causing harm to aquatic ecosystems, including plants and animals, and to humans via direct exposure to water-borne toxins or by toxic seafood consumption. Ecosystem damage by high-biomass blooms may include, for instance, disruption of food webs, fish-killing by gill damage, or contribution to low oxygen “dead-zones” after bloom degradation. Some species also produce potent natural chemicals (toxins) that can persist in the water or enter the food web, leading to illness or death of aquatic animals and/or human seafood consumers

    Estimating population birth rates of zooplankton when rates of egg deposition and hatching are periodic

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    I present a general method of computing finite birth and death rates of natural zooplankton populations from changes in the age distribution of eggs and changes in population size. The method is applicable to cases in which eggs hatch periodically owing to variable rates of oviposition. When morphological criteria are used to determine the age distribution of eggs at the beginning and end of a sampling interval, egg mortality can be incorporated in estimates of population birth rate. I raised laboratory populations of Asplanchna priodonta , a common planktonic rotifer, in semicontinuous culture to evaluate my method of computing finite birth rate. The Asplanchna population became synchronized to a daily addition of food but grew by the same amount each day once steady state was achieved. The steady-state rate of growth, which can be computed from the volume-specific dilution rate of the culture, was consistent with the finite birth rate predicted from the population's egg ratio and egg age distribution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47764/1/442_2004_Article_BF00410359.pd

    Sythesis of L-amino acids from hydroxy analogs with substrate-bound cofactor regeneration

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    Leuchtenberger W. Sythesis of L-amino acids from hydroxy analogs with substrate-bound cofactor regeneration. In: Magnien E, ed. Biomolecular Engineering in the European Community. EUR. Vol 10658. Dordrecht: Nijhoff; 1986: 227-240

    Culture System Invitro for Field Bean (vicia-faba L)

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