Your browser doesn't support javascript.
loading
Benefit of pulsation in soft corals.
Kremien, Maya; Shavit, Uri; Mass, Tali; Genin, Amatzia.
Afiliação
  • Kremien M; Heinz Steinitz Marine Biology Laboratory, Interuniversity Institute for Marine Sciences, Eilat 88103, Israel. maya.kremien@mail.huji.ac.il
Proc Natl Acad Sci U S A ; 110(22): 8978-83, 2013 May 28.
Article em En | MEDLINE | ID: mdl-23610420
Soft corals of the family Xeniidae exhibit a unique, rhythmic pulsation of their tentacles (Movie S1), first noted by Lamarck nearly 200 y ago. However, the adaptive benefit of this perpetual, energetically costly motion is poorly understood. Using in situ underwater particle image velocimetry, we found that the pulsation motions thrust water upward and enhance mixing across the coral-water boundary layer. The induced upward motion effectively prevents refiltration of water by neighboring polyps, while the intensification of mixing, together with the upward flow, greatly enhances the coral's photosynthesis. A series of controlled laboratory experiments with the common xeniid coral Heteroxenia fuscescens showed that the net photosynthesis rate during pulsation was up to an order of magnitude higher than during the coral's resting, nonpulsating state. This enhancement diminished when the concentration of oxygen in the ambient water was artificially raised, indicating that the enhancement of photosynthesis was due to a greater efflux of oxygen from the coral tissues. By lowering the internal oxygen concentration, pulsation alleviates the problem of reduced affinity of ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO) to CO2 under conditions of high oxygen concentrations. The photosynthesis-respiration ratio of the pulsating H. fuscescens was markedly higher than the ratios reported for nonpulsating soft and stony corals. Although pulsation is commonly used for locomotion and filtration in marine mobile animals, its occurrence in sessile (bottom-attached) species is limited to members of the ancient phylum Cnidaria, where it is used to accelerate water and enhance physiological processes.
Assuntos
Palavras-chave

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Fotossíntese / Antozoários / Extremidades / Movimento Limite: Animals Idioma: En Revista: Proc Natl Acad Sci U S A Ano de publicação: 2013 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Fotossíntese / Antozoários / Extremidades / Movimento Limite: Animals Idioma: En Revista: Proc Natl Acad Sci U S A Ano de publicação: 2013 Tipo de documento: Article