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Lookup NU author(s): Dr Benjamin Wigham
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Using a Remotely Operated Vehicle (ROV) to deploy an in situ cage experiment incorporating fluorescent Luminophore particle tracers, the gut throughput time of the deposit feeding holothurian, Stichopus tremulus (Gunnerus) was determined as 23.73 h (S.D +/- 2.3). For a range of individuals examined at different depths (350-500 m) and locations, throughput times varied between 19 and 26 It irrespective of animal size or gut tract length. In situ video observations of feeding behaviour showed that this species uses fine oral papillae in a 'sweeping' motion to target particles on the seafloor. Following detection of a food source fine-branched digitate tentacles collect a large range of sediment fragments from the seabed. The main types of particles ingested include silica fragments (<20>500 mum), pelagic foraminifera, benthic foraminifera, fine phytodetrital remains and occasional larger rock fragments ( similar to 1 cm). Ingested sediment consisted mainly of very fine silica fragments ( similar to 50 mum) accounting for over 50% of the total gut contents. Frame-by-frame video analysis revealed that the particle handling time (i.e. the time taken for a tentacle insertion and the subsequent collection of food) was found to be similar to 54 s. Only 10 of the 20 feeding tentacles were simultaneously employed during feeding. Use of tentacles appeared to be in sequence, alternating between the reserve and active tentacles. Estimating the rate of movement over the seabed and the total effective capture area of each tentacle, the impact of this animal on the turnover and quality of surface sediment at this deepwater site is potentially substantial. The in situ experiments provided a significant improvement over previous methods used to investigate deep-sea deposit feeders and represent a useful concept for further in situ deep-sea research using an industrial ROV. (C) 2003 Elsevier B.V. All rights reserved.
Author(s): Hudson RR, Wigham BD, Tyler PA
Publication type: Article
Publication status: Published
Journal: Journal of Experimental Marine Biology and Ecology
ISSN (print): 0022-0981
Publisher: Elsevier BV
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