QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online October 30, 2009
Journal of Experimental Biology 212, 3643-3650 (2009)
Published by The Company of Biologists 2009
doi: 10.1242/jeb.027953

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Hadas, E. Articles by Ilan, M. PubMed PubMed Citation Articles by Hadas, E. Articles by Ilan, M. Social Bookmarking                         What's this?

Particulate organic matter as a food source for a coral reef sponge

E. Hadas^1,2, M. Shpigel³ and M. Ilan^1,*

¹ Department of Zoology, Tel Aviv University, Tel Aviv, 69978, Israel
² Interuniversity Institute of Marine Sciences in Eilat, P.O. Box 469, Eilat, 88103, Israel
³ Israel Oceanographic and Limnological Research, National Center for Mariculture, Eilat, 88112, Israel

^* Author for correspondence (Milan{at}post.tau.ac.il)

Accepted 12 August 2009

The ability of sponges to feed in diverse (including oligotrophic) ecosystems significantly contributes to their ubiquitous aquatic distribution. It was hypothesized that sponges that harbour small amounts of symbiotic bacteria in their mass feed mainly on particulate organic matter (POM). We examined the nearly symbiont-free (by microscopic observation) filter-feeding Red Sea sponge Negombata magnifica in order to: (a) study removal efficiency of naturally occurring organic particles, (b) measure the total amount of absorbed particulate organic carbon (POC) and nitrogen (PON), and (c) estimate organic carbon and nitrogen flux in this sponge. Total amount of organic carbon and nitrogen in the Gulf of Aqaba was found to be 48.46±5.69 µg l^–1 and 6.45±0.7 µg l^–1, respectively. While detritus contributed 54% of POC, most PON (84%) came from planktonic microorganisms, mainly prokaryotes. Particle removal efficiency ranged from 99% (the cyanobacterium Synechococcus sp.) to 37% (for eukaryotic cells >8 µm). On average, N. magnifica ingested 480 µg C day^–1 g^–1 (wet mass, WM) sponge and 76.6 µg N day^–1 g^–1 sponge. Ingested POC balanced 85% of the sponge's energetic demand but more is needed for biomass production because it cannot digest all of the carbon. 54.4±16.1 µg N day^–1 g^–1 (WM) nitrogen was excreted as total ammonia nitrogen (TAN); however, nitrogen allowance should be higher because more nitrogen is deposited for sponge biomass during growth. It is hypothesized that the discrepancy in the nutritional requirements should be covered by the sponge absorbing carbon and nitrogen from sources that are not dealt with in the present research, such as dissolved organic carbon and nitrogen. This study highlights the significance of detritus as a carbon source, and prokaryotes as a PON source in sponge feeding.

Key words: Porifera, coral reef, filtration, flow cytometry

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?