Natural feeding of the temperate asymbiotic octocoral-gorgonian Leptogorgia sarmentosa (Cnidaria: Octocorallia)

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 254:141-150 (2003) - doi:10.3354/meps254141 Natural feeding of the temperate asymbiotic octocoral-gorgonian Leptogorgia sarmentosa (Cnidaria: Octocorallia) Marta Ribes1,4,*, Rafel Coma2, Sergi Rossi3 1Hawaii Institute of Marine Biology, PO Box 1346, Kaneohe, Hawaii 96744, USA 2Centre d¹Estudis Avançats de Blanes (CSIC), Accés Cala Sant Francesc 14, PO BOX 118, 17300 Blanes, Girona, Spain 3Institut de Ciències del Mar (CSIC), Passeig Marítim 37-49, 08003 Barcelona, Spain 4Present address: Institut de Ciències del Mar (CSIC), Passeig Marítim 37-49, 08003 Barcelona, Spain *Email: mribes@icm.csic.es ABSTRACT: Octocorals are common components of sublittoral benthic communities in temperate, tropical and polar areas. However, their natural diets and feeding rates are poorly known. In this study, we examined natural feeding and respiration of the ubiquitous temperate species Leptogorgia sarmentosa (Cnidaria: Octocorallia) in the NW Mediterranean. We measured in situ grazing rate on dissolved organic carbon (DOC), detrital particulate organic carbon (POC) and live particulate carbon <100 µm (i.e. pico- and nanoplankton, dinoflagellates, diatoms and ciliates) using continuous flow incubation chambers. L. sarmentosa captured nanoeukaryotes, dinoflagellates, diatoms, ciliates, as well as detrital POC, but no significant capture of DOC, nor of prey items smaller than nanoeukaryotes (mean 3.6 µm), was observed. Feeding rate on detrital POC and live carbon <100 µm was 402 ± 35 and 67 ± 6 µg C g ash-free dry mass (AFDM)-1 h-1, respectively. Detrital POC and zooplankton‹previously studied‹were the 2 main food sources, while live carbon <100 µm accounted for less than 10% of the total ingested carbon. Respiration rate was 0.55 ± 0.24 mg O2 g AFDM-1 h-1 (mean ± SE), which is equivalent to a requirement of 155 ± 67 µg C g AFDM-1 h-1. On the basis of estimated feeding and respiration rates, the respiratory demand can largely be met. The spectrum of food sources and the contribution of different food sources to the diet is consistent with previous feeding studies and suggests 2 general patterns in the diet of octocorals. First, octocorals feed on a wide spectrum of food sources ranging from ca. 4 µm (nanoeukaryotes) to seston particles measuring several hundred microns. Second, despite the wide spectrum of food sources, microplankton and detrital POC constitute the bulk of the heterotrophic diet of octocorals. The contribution of detrital POC to the diet of octocorals suggests that there may be important seasonal variations in energy intake, which may affect the seasonal dynamics of temperate octocorals due to the marked seasonal variation in the availability of this particulate carbon source in temperate ecosystems like the Mediterranean. KEY WORDS: Octocorals · Natural feeding · Respiration · Gorgonians · Benthic communities · Mediterranean Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 254. Online publication date: June 04, 2003 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2003 Inter-Research.