Trophic ecology of the zoanthidPalythoa caribaeorum(Cnidaria: Anthozoa) on tropical reefs

Abstract

This study examined the trophic ecology of the zoanthid Palythoa caribaeorum in tropical reefs and evaluated its role in the energy flow in that ecosystem. Colonies of this species were sampled in the infralittoral zone of reefs in north-eastern Brazil in 2008. We calculated the richness, total abundance, relative abundance and frequency of occurrence of prey items. The biovolumes and weighted biovolumes of prey were calculated to characterize the most important food items in terms of their biomasses. To evaluate the selectivity, zoanthid and plankton samples were collected in 2010. Pennate diatoms were the most abundant and most frequent prey and, together with invertebrate eggs, constituted the most important food items in terms of their biomasses. There were no significant differences in abundance or richness among the different beaches studied, nor between the different seasons. The mean size of prey items within the polyps was significantly smaller than of the general plankton, indicating that P. caribaeorum selected for (or limited) certain prey sizes. This species predominantly fed on diatoms, and did not take advantage of many other prey items abundant in the plankton. Our results indicate that P. caribaeorum is suspensivorous and feeds principally on small phytoplankton. As this species is prey for benthic organisms such as polychaetes and nektonic organisms, our results indicate the importance of this zoanthid in tropical reef ecosystems as a primary consumer that serves as an energy transfer link between the planktonic environment and the nektonic and benthic spheres.

The Transcriptome of the ZoanthidProtopalythoa variabilis(Cnidaria, Anthozoa) Predicts a Basal Repertoire of Toxin-like and Venom-Auxiliary Polypeptides

“…Consequently, P. variabilis may rely on neurotoxic, hemorrhagic, and membranolytic toxins as molecular weapons to fend off predators. Moreover, the trophic ecology of P. variabilis demonstrated a suspensivorous feeding behavior (personal communication) that is similar to that of Palythoa caribaeorum along the Pernambuco Coast (Northeast Brazil) ( de Santana et al 2015 ). In contrast, the marine annelids of the genus Glycera that were once believed to be detritivorous were recently repositioned as an effective predator after the transcriptomic description of the complex cocktail of toxin precursors that are present in the Glycera venom gland ( von Reumont et al 2014 ).…”

The effect of climate change on the distribution of a tropical zoanthid (Palythoa caribaeorum) and its ecological implications

“…P. caribaeorum is a mixotrophic organism, hosting symbiotic dinoflagellates ( Symbiodinium ) inside its tissues ( Sebens, 1977 ; Suchanek & Green, 1981 ) and feeding on planktonic organisms, which contributes to the energy flux from plankton to benthic environments ( Sorokin, 1991 ; Santana et al, 2015 ). Few studies have highlighted the importance of P. caribaeorum in association with other invertebrates ( Pérez, Vila-Nova & Santos, 2005 ), reef dynamics ( Silva et al, 2015 ), or the enrichment of the bottom fish community ( Mendonça-Neto et al, 2008 ).…”

Diversity of Feeding in Anthozoa (Cnidaria): A Systematic Review

“…Another topic rarely addressed that deserves more research attention is the trophic position of different species of anthozoans. According to the studies ( [13]; [36]; [37]) the vast majority are primary or secondary consumers, but other species appear to at least be occasional higher-level predators [38].…”