Do meiofauna consume primary production?: about many questions and how to answer them
Moens, T.; Vincx, M. (1996). Do meiofauna consume primary production?: about many questions and how to answer them, in: Baeyens, J. et al. (Ed.) Integrated Marine System Analysis. European Network for Integrated Marine System Analysis. FWO Vlaanderen: minutes of the first network meeting (Brugge, 29.02.96-02.03.96). pp. 188-202
In: Baeyens, J. et al. (Ed.) (1996). Integrated Marine System Analysis. European Network for Integrated Marine System Analysis. FWO Vlaanderen: minutes of the first network meeting (Brugge, 29.02.96-02.03.96). Vrije Universiteit Brussel. Laboratorium voor Analytische Chemie: Brussel. 217 pp., meer
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Documenttype: Congresbijdrage
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| Abstract |
In view of their densities, benthic meiofauna are potentially important consumers of primary production. Feeding on diatoms and other microalgae has been documented in a variety of benthic meiotaxa, including many species of the numerically dominant nematodes and harpacticoids. Still, a detailed account of the exact diet of most species, and of the quantitative importance of primary producers in it, is lacking. For nematodes, the presumed nutritive importance of diatoms mostly derives from rather hypothetical links between buccal morphology and food. On the basis of such links, the proportion of nematodes supposedly feeding on the diatoms may amount to as much as 85%, suggesting meiofauna to importantly graze on microalgae. In estuarine and shallow coastal environments, the importance of photoautotrophs for meiofauna is further supported by correlations of meiofauna abundance patterns to phytopigment concentrations. However, as observations on the feeding behaviour of nematodes increasingly show the bias involved in stringently linking morphological characters to food, any quantification of grazing based merely on this kind of information remains putative. As many meiofauna are opportunistic feeders, which may change feeding behaviour in relation to available food, no simple relations between meiofauna and primary production can be drawn. Published estimates of meiofauna grazing on benthic bacteria and microalgae on average approximate 0,01 h-1 (Montagna, 1995). Put differently: meiofauna consume about 1% of bacterial and microalgal standing stock per hour, which suggests a tight coupling of benthic meiofauna to benthic microbiota (Montagna, 1995). There are, however, serious flaws in the presently used techniques to measure meiofaunal microbivory, and questions pertaining to relevant experimental incubation times, sample preservation procedure, periodicity in meiofauna feeding activity etc. have so far received too little attention. While from the foregoing, it is obvious that important questions about quantitative aspects of the links between primary production and meiofauna remain unanswered, it becomes increasingly clear that, apart from direct grazing, other interactions, e.g. involving exopolysaccharide secretions, may exist between microalgae, bacteria and meiofauna. |
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