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Role of bacteria in decomposition of faecal pellets egested by the epiphyte-grazing gastropod Gibbula umbilicaris

Role of bacteria in decomposition of faecal pellets egested by the epiphyte-grazing gastropod... 227 92 92 3 3 P. Peduzzi G. J. Herndl Institute for Zoology University of Vienna Althanstraße 14 A-1090 Vienna Austria Abstract The significance of the microheterotrophic utilization of faecal pellets derived from Gibbula umbilicaris — one of the most important gastropod species in the Posidonia oceanica ecosystem around the Isle of Ischia (Italy) — was investigated by means of microcosm-experiments. Initial total organic carbon (TOC) content of faecal pellets was 32 μgC (mg faeces dry wt) -1 and declined continuously over a 2-month incubation period. The low values of TOC coincided with SEM observations of pellets which were found to consist mainly of diatom frustules and other slowly utilizable material. In a long-term experiment freshly egested faecal pellets were rapidly colonized by bacteria, which reached densities of up to 14x10 5 cells (mg faeces dry wt) -1 within 12 h. Thereafter bacterial numbers declined and fluctuated in a very narrow range between 2 and 3.5x10 5 cells (mg faeces dry wt) -1 during the two months of the investigation period. In short-term experiments (over 5 d) similar trends were observed. Peak densities of attached bacteria were followed by a decline of this population. Concurrently the number of free-living bacteria increased. This observation was confirmed by O 2 consumption measurements of freshly egested faecal pellets over 24 h, where the highest O 2 consumption rates were obtained after 12 h, followed by a rapid decline, thus supporting the view that detachment of bacteria may occur. Moreover, the respiration data indicate that about 4% of faecal TOC are remineralized within the first day. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Marine Biology Springer Journals

Role of bacteria in decomposition of faecal pellets egested by the epiphyte-grazing gastropod Gibbula umbilicaris

Marine Biology , Volume 92 (3) – Aug 1, 1986

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References (40)

Publisher
Springer Journals
Copyright
Copyright © 1986 by Springer-Verlag
Subject
Life Sciences; Biomedicine general; Oceanography; Ecology; Microbiology; Zoology
ISSN
0025-3162
eISSN
1432-1793
DOI
10.1007/BF00392682
Publisher site
See Article on Publisher Site

Abstract

227 92 92 3 3 P. Peduzzi G. J. Herndl Institute for Zoology University of Vienna Althanstraße 14 A-1090 Vienna Austria Abstract The significance of the microheterotrophic utilization of faecal pellets derived from Gibbula umbilicaris — one of the most important gastropod species in the Posidonia oceanica ecosystem around the Isle of Ischia (Italy) — was investigated by means of microcosm-experiments. Initial total organic carbon (TOC) content of faecal pellets was 32 μgC (mg faeces dry wt) -1 and declined continuously over a 2-month incubation period. The low values of TOC coincided with SEM observations of pellets which were found to consist mainly of diatom frustules and other slowly utilizable material. In a long-term experiment freshly egested faecal pellets were rapidly colonized by bacteria, which reached densities of up to 14x10 5 cells (mg faeces dry wt) -1 within 12 h. Thereafter bacterial numbers declined and fluctuated in a very narrow range between 2 and 3.5x10 5 cells (mg faeces dry wt) -1 during the two months of the investigation period. In short-term experiments (over 5 d) similar trends were observed. Peak densities of attached bacteria were followed by a decline of this population. Concurrently the number of free-living bacteria increased. This observation was confirmed by O 2 consumption measurements of freshly egested faecal pellets over 24 h, where the highest O 2 consumption rates were obtained after 12 h, followed by a rapid decline, thus supporting the view that detachment of bacteria may occur. Moreover, the respiration data indicate that about 4% of faecal TOC are remineralized within the first day.

Journal

Marine BiologySpringer Journals

Published: Aug 1, 1986

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