Cargando…

The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.

Global climate change not only leads to elevated seawater temperatures but also to episodic anomalously high or low temperatures lasting for several hours to days. Scleractinian corals are detrimentally affected by thermal fluctuations, which often lead to an uncoupling of their mutualism with Symbi...

Descripción completa

Detalles Bibliográficos
Autores principales: Goulet, Tamar L., Shirur, Kartick P., Ramsby, Blake D., Iglesias-Prieto, Roberto
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5289496/
https://www.ncbi.nlm.nih.gov/pubmed/28152002
http://dx.doi.org/10.1371/journal.pone.0171032
_version_ 1782504505093390336
author Goulet, Tamar L.
Shirur, Kartick P.
Ramsby, Blake D.
Iglesias-Prieto, Roberto
author_facet Goulet, Tamar L.
Shirur, Kartick P.
Ramsby, Blake D.
Iglesias-Prieto, Roberto
author_sort Goulet, Tamar L.
collection PubMed
description Global climate change not only leads to elevated seawater temperatures but also to episodic anomalously high or low temperatures lasting for several hours to days. Scleractinian corals are detrimentally affected by thermal fluctuations, which often lead to an uncoupling of their mutualism with Symbiodinium spp. (coral bleaching) and potentially coral death. Consequently, on many Caribbean reefs scleractinian coral cover has plummeted. Conversely, gorgonian corals persist, with their abundance even increasing. How gorgonians react to thermal anomalies has been investigated utilizing limited parameters of either the gorgonian, Symbiodinium or the combined symbiosis (holobiont). We employed a holistic approach to examine the effect of an experimental five-day elevated temperature episode on parameters of the host, symbiont, and the holobiont in Eunicea tourneforti, E. flexuosa and Pseudoplexaura porosa. These gorgonian corals reacted and coped with 32°C seawater temperatures. Neither Symbiodinium genotypes nor densities differed between the ambient 29.5°C and 32°C. Chlorophyll a and c(2) per Symbiodinium cell, however, were lower at 32°C leading to a reduction in chlorophyll content in the branches and an associated reduction in estimated absorbance and increase in the chlorophyll a specific absorption coefficient. The adjustments in the photochemical parameters led to changes in photochemical efficiencies, although these too showed that the gorgonians were coping. For example, the maximum excitation pressure, Q(m), was significantly lower at 32°C than at 29.5°C. In addition, although per dry weight the amount of protein and lipids were lower at 32°C, the overall energy content in the tissues did not differ between the temperatures. Antioxidant activity either remained the same or increased following exposure to 32°C further reiterating a response that dealt with the stressor. Taken together, the capability of Caribbean gorgonian corals to modify symbiont, host and consequently holobiont parameters may partially explain their persistence on reefs faced with climate change.
format Online
Article
Text
id pubmed-5289496
institution National Center for Biotechnology Information
language English
publishDate 2017
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-52894962017-02-17 The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp. Goulet, Tamar L. Shirur, Kartick P. Ramsby, Blake D. Iglesias-Prieto, Roberto PLoS One Research Article Global climate change not only leads to elevated seawater temperatures but also to episodic anomalously high or low temperatures lasting for several hours to days. Scleractinian corals are detrimentally affected by thermal fluctuations, which often lead to an uncoupling of their mutualism with Symbiodinium spp. (coral bleaching) and potentially coral death. Consequently, on many Caribbean reefs scleractinian coral cover has plummeted. Conversely, gorgonian corals persist, with their abundance even increasing. How gorgonians react to thermal anomalies has been investigated utilizing limited parameters of either the gorgonian, Symbiodinium or the combined symbiosis (holobiont). We employed a holistic approach to examine the effect of an experimental five-day elevated temperature episode on parameters of the host, symbiont, and the holobiont in Eunicea tourneforti, E. flexuosa and Pseudoplexaura porosa. These gorgonian corals reacted and coped with 32°C seawater temperatures. Neither Symbiodinium genotypes nor densities differed between the ambient 29.5°C and 32°C. Chlorophyll a and c(2) per Symbiodinium cell, however, were lower at 32°C leading to a reduction in chlorophyll content in the branches and an associated reduction in estimated absorbance and increase in the chlorophyll a specific absorption coefficient. The adjustments in the photochemical parameters led to changes in photochemical efficiencies, although these too showed that the gorgonians were coping. For example, the maximum excitation pressure, Q(m), was significantly lower at 32°C than at 29.5°C. In addition, although per dry weight the amount of protein and lipids were lower at 32°C, the overall energy content in the tissues did not differ between the temperatures. Antioxidant activity either remained the same or increased following exposure to 32°C further reiterating a response that dealt with the stressor. Taken together, the capability of Caribbean gorgonian corals to modify symbiont, host and consequently holobiont parameters may partially explain their persistence on reefs faced with climate change. Public Library of Science 2017-02-02 /pmc/articles/PMC5289496/ /pubmed/28152002 http://dx.doi.org/10.1371/journal.pone.0171032 Text en © 2017 Goulet et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Goulet, Tamar L.
Shirur, Kartick P.
Ramsby, Blake D.
Iglesias-Prieto, Roberto
The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.
title The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.
title_full The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.
title_fullStr The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.
title_full_unstemmed The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.
title_short The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.
title_sort effects of elevated seawater temperatures on caribbean gorgonian corals and their algal symbionts, symbiodinium spp.
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5289496/
https://www.ncbi.nlm.nih.gov/pubmed/28152002
http://dx.doi.org/10.1371/journal.pone.0171032
work_keys_str_mv AT goulettamarl theeffectsofelevatedseawatertemperaturesoncaribbeangorgoniancoralsandtheiralgalsymbiontssymbiodiniumspp
AT shirurkartickp theeffectsofelevatedseawatertemperaturesoncaribbeangorgoniancoralsandtheiralgalsymbiontssymbiodiniumspp
AT ramsbyblaked theeffectsofelevatedseawatertemperaturesoncaribbeangorgoniancoralsandtheiralgalsymbiontssymbiodiniumspp
AT iglesiasprietoroberto theeffectsofelevatedseawatertemperaturesoncaribbeangorgoniancoralsandtheiralgalsymbiontssymbiodiniumspp
AT goulettamarl effectsofelevatedseawatertemperaturesoncaribbeangorgoniancoralsandtheiralgalsymbiontssymbiodiniumspp
AT shirurkartickp effectsofelevatedseawatertemperaturesoncaribbeangorgoniancoralsandtheiralgalsymbiontssymbiodiniumspp
AT ramsbyblaked effectsofelevatedseawatertemperaturesoncaribbeangorgoniancoralsandtheiralgalsymbiontssymbiodiniumspp
AT iglesiasprietoroberto effectsofelevatedseawatertemperaturesoncaribbeangorgoniancoralsandtheiralgalsymbiontssymbiodiniumspp