Trophic biology of Stylophora pistillata larvae: evidence from stable isotope analysis

Abstract

The successful recruitment of planktonic larvae to coral reefs is essential for the continued existence of these highly diverse ecosystems. Feeding strategies may affect recruitment success and potentially determine species distribution by controlling the dispersal range of the larvae. Our aim here was to ascertain the feeding strategies of planula larvae of the coral Stylophora pistillata by using stable isotopes. Planula larvae, fragments of parental colonies, and 3 potential food types were analyzed for carbon and nitrogen stable isotope compositions and C/N ratios. We found that planulae were depleted in 13 C when compared to parental tissues, whereas their C/N ratios were 2-fold higher. Following lipid extraction, there were no significant differences in δ 13 C values and C/N ratios between lipid-free planulae and parental colonies. This indicates that the differences in δ 13 C originate in the lipid content of the planulae and not from any isotopic fractionation that may occur during embryological development. Controlled feeding experiments were conducted using phytoplankton, zooplankton, and bacteria. Despite the presence of an oral opening, the planulae did not show any feeding behavior, and the stable isotope data corroborated the observations of no feeding. Moreover, following 2 wk of starvation in the dark, planulae started to utilize their lipid and protein reservoirs. These results stress the importance of the photosynthates translocated from the algal symbionts to these planulae as an energy source.

Carbon and nitrogen utilization in two species of Red Sea corals along a depth gradient: Insights from stable isotope analysis of total organic material and lipids

“…À21&, Lorian, 1991). The observed trends in the bulk samples of these coral species from the Gulf of Aqaba generally agree with earlier findings for Caribbean corals (Land et al, 1975;Muscatine et al, 1989) and coral larvae in the Gulf of Aqaba (Alamaru et al, 2009). However, the depletion trend in the Gulf of Aqaba was noticed only between 15 and 60 m. At the upper most 15 m there is no significant change in the isotopic composition of carbon in the bulk tissue and zooxanthellae ( Fig.…”

Effects of temperature and pCO 2 on lipid use and biological parameters of planulae of Pocillopora damicornis

“…Additionally, OA could increase energetic demands by eliciting cellular stress response, oxidative defense, and ion-balance pathways in the host tissue. Without sufficient metabolite input from Symbiodinium under future ocean conditions, coral larvae consume their lipid and protein stores at faster rates (Alamaru et al, 2009;Ben-David-Zaslow and Benayahu, 2000;Harii et al, 2010). In particular, wax ester consumption increases when endosymbiont metabolites are not available (Harii et al, 2010).…”

“…Most coral planulae are rich in maternally derived lipids (e.g. Ward, 1992), whose energy stores largely determine the length of their larval duration and competency period (Alamaru et al, 2009;Arai et al, 1993;Harii et al, 2002Harii et al, , 2007Richmond, 1987;Wellington and Fitt, 2003).…”

A test of alternate models for increased tissue nitrogen isotope ratios during fasting in hibernating arctic ground squirrels

“…N values in tissues during fasting or nutritional stress (Hobson et al, 1993;Scrimgeour et al, 1995;Fuller et al, 2005;Boag et al, 2006;Alamaru et al, 2009). However, a growing number of studies have either failed to observe an increase (Castillo and Hatch, 2007;Kempster et al, 2007;McCue and Pollock, 2008;McFarlane Tranquilla et al, 2010;Mayor et al, 2011) or only detected it in specific tissues (Doucett et al, 1999;Gloutney et al, 1999;Cherel et al, 2005;Guelinckx et al, 2007).…”