Towards a predictive model supporting coral reef management of Bonaire's coral reef. Progress report 2012
Meesters, H.W.G. ; Brinkman, A.G. ; Duyl, F.C. van; Gerla, D.J. ; Groot, A.V. de; Meer, J. van der; Ruardij, P. ; Vries, P. de - \ 2013
Den Burg : IMARES (Report / IMARES Wageningen UR C070/13) - 10
coral reefs - models - environmental management - aquatic environment - bonaire - koraalriffen - modellen - milieubeheer - aquatisch milieu - bonaire
Coral cavity sponges depend on reef-derived food resources: stable isotope and fatty acid constraints
Duyl, F.C. van; Moodley, L. ; Nieuwland, G. ; Ijzerloo, L. van; Soest, R.W.M. ; Houtekamer, M. ; Meesters, H.W.G. ; Middelburg, J.J. - \ 2011
Marine Biology 158 (2011)7. - ISSN 0025-3162 - p. 1653 - 1666.
organic-matter release - situ o-2 availability - nitrogen-fixation - bacterioplankton growth - symbiotic zooxanthellae - netherlands-antilles - halisarca-caerulea - primary producers - mucus production - carbon-isotope
The diet of cavity sponges on the narrow fringing reefs of Cura double dagger ao, Caribbean was studied. The origin and resources of the bulk food of these sponges, i.e., dissolved organic matter (DOM), were identified using stable carbon and nitrogen isotopes and fatty acid biomarkers. We found that phytoplankton and its derived DOM from the adjacent open sea and from reef overlying water is not the main source of food for most of the sponges examined nor is bacterioplankton. Interestingly, dual stable isotope signatures (delta(13)C(org), delta(15)N(org)) and fatty acid biomarkers appoint coral mucus and organic matter derived from crustose coralline algae (CCA) as probable food sources for encrusting sponges. Mucus-derived DOM may contribute up to 66% to the diet of examined sponges based on results of dual isotope mixing model analysis. The contribution of CCA (as purported representative for benthic algae) was smaller with values up to 31%. Together, mucus- and CCA-derived substrates contributed for 48-73% to the diet of sponges. The presence of the exogenous fatty acid 20:4 omega 6 in sponges, which is abundant in coral mucus of Madracis mirabilis and in CCA, highlights these reef-derived resources as sources of nutrition for DOM feeding cavity sponges. The relatively high concentrations of exogenous 20:4 omega 6 in all sponges examined supports our hypothesis that the bulk of the food of the cavity sponge community is reef-derived. Our results imply that cavity sponges play an important role in conserving food and energy produced within the reef.
Cell kinetics of the marine sponge Halisarca caerulea reveal rapid cell turnover and shedding
Goeij, J.M. de; Kluijver, A. de; Duyl, F.C. van; Vacelet, J. ; Wijffels, R.H. ; Goeij, A.F.P.M. de; Cleutjens, J.P.M. ; Schutte, B. - \ 2009
Journal of Experimental Biology 212 (2009)23. - ISSN 0022-0949 - p. 3892 - 3900.
organic-carbon doc - telomerase activity - suspension feeders - hydra-attenuata - cycle kinetics - iv collagen - porifera - demospongiae - removal - death
This study reveals the peculiar in vivo cell kinetics and cell turnover of the marine sponge Halisarca caerulea under steady-state conditions. The tropical coral reef sponge shows an extremely high proliferation activity, a short cell cycle duration and massive cell shedding. Cell turnover is predominantly confined to a single cell population, i.e. the choanocytes, and in this process apoptosis only plays a minor role. To our knowledge, such fast cell kinetics under steady-state conditions, with high turnover by shedding in the absence of apoptosis, has not been observed previously in any other multicellular organism. The duration of the cell cycle in vivo resembles that of unicellular organisms in culture. Morphological and histochemical studies demonstrate compartmentalization of choanocytes in the sponge tissue, which corresponds well with its remarkable cellular kinetics. Coral reef cavity sponges, like H. caerulea, inhabit low nutrient tropical waters, forcing these organisms to filter large volumes of water and to capture the few nutrients efficiently. Under these oligotrophic conditions, a high cell turnover may be considered as a very useful strategy, preventing permanent damage to the sponge by environmental stress. Halisarca caerulea maintains its body mass and keeps its food uptake system up to date by constantly renewing its filter system. We conclude that studies on cell kinetics and functional morphology provide new and essential information on the growth characteristics and the regulation of sponge growth in vivo as well as in vitro and the role of choanocytes in tissue homeostasis