Excretion and body composition of the ctenophore Mneniopsis leidyi (A. Agassiz): comparisons and consequences
Kremer, P. (1976). Excretion and body composition of the ctenophore Mneniopsis leidyi (A. Agassiz): comparisons and consequences, in: Persoone, G. et al. (Ed.) Proceedings of the 10th European Symposium on Marine Biology, Ostend, Belgium, Sept. 17-23, 1975: 2. Population dynamics of marine organisms in relation with nutrient cycling in shallow waters. pp. 351-362 In: Persoone, G.; Jaspers, E. (Ed.) (1976). Proceedings of the 10th European Symposium on Marine Biology, Ostend, Belgium, Sept. 17-23, 1975: 2. Population dynamics of marine organisms in relation with nutrient cycling in shallow waters. European Marine Biology Symposia, 10(2). IZWO/Universa Press: Wetteren. ISBN 90-6281-002-0. 712 pp., more In: European Marine Biology Symposia., more |
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| Abstract | Analyses of the body composition of Mnemiopsis leidyi demonstrated that the dry weight comprised less than 4 % of the wet weight, and contained about 80 % ash and 1.7 % carbon. The elemental carbon: nitrogen: phosphorus ratio (by atoms) of the tissue was 122: 31: 1. In the excretion products, the corresponding ratio was 36.5:7.4:1 for the dissolved inorganic- and 46.7:11:1 for total dissolved compounds. Inorganic nitrogen, exclusively ammonia, made up about 54 % of the release of total dissolved nitrogen. Similarly, the release of carbon dioxide was only slightly more than the release of dissolved organic carbon. By contrast, reactive phosphorus comprised about 80 % of the total dissolved phosphorus. These ratios remained fairly constant for all temperatures (10.3-24.5 °C) and various sizes of organisms tested. The enrichment of excreted phosphorus relative to the body composition was probably the consequence of the ingestion of zooplankton with a lower body N:P ratio. The calculated impact of the peak summer biomass of Mnemiopsis on nutrient turnover in the water column, was greatest for ammonia, representing 0.25-25 % turnover/day. During the late summer, the ctenophores are one of the major nutrient recyclers in Narragansett Bay, and through their voracious feeding (zooplankton) and excretion, they may significantly stimulate primary production. |
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