Differences in physiological response to increased seawater temperature in nearshore and offshore corals in northern Vietnam

Effects of elevated seawater temperature show high spatial heterogeneity and variation within and among coral species. The objective of this study was to investigate how two coral species, Porites lutea and Galaxea fascicularis, from two high latitude reefs differently exposed to chronic disturbance...

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Bibliographic Details
Published in:	Marine environmental research Vol. 71; no. 3; pp. 225 - 233
Main Authors:	Faxneld, Suzanne, Jörgensen, Tove Lund, Nguyen, Ngai D., Nyström, Magnus, Tedengren, Michael
Format:	Journal Article
Language:	English
Published:	Oxford Elsevier Ltd 01-04-2011 Elsevier Elsevier science
Subjects:	Animal and plant ecology Animal, plant and microbial ecology Animals Anthozoa - metabolism Anthozoa - physiology Biological and medical sciences Chlorophyll - metabolism Cnidaria. Ctenaria Coral Reefs Corals Disturbance Elevated Environmental Monitoring Exposure Fundamental and applied biological sciences. Psychology Galaxea fasciculari Galaxea fascicularis Heat treatment High latitude reefs Hot Temperature Increased water temperature Invertebrates Life Sciences marin ekotoxikologi Marine Marine Ecotoxicology Offshore Offshore engineering Offshore structures Physiological responses Porites lutea Reefs Sea water Sea water ecosystems Seawater - chemistry Species Specificity Stress, Physiological Synecology Vietnam Asia Vietnam ISEW, Vietnam Vietnam Increased water temperature Galaxea fascicularis Disturbance Porites lutea High latitude reefs Physiological responses High latitude Temperature Perturbation Marine environment Coelenterata Offshore Reef Coral Cnidaria Invertebrata Seawater
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Summary:	Effects of elevated seawater temperature show high spatial heterogeneity and variation within and among coral species. The objective of this study was to investigate how two coral species, Porites lutea and Galaxea fascicularis, from two high latitude reefs differently exposed to chronic disturbance, respond to elevated seawater temperatures. Corals were collected from reefs nearshore (i.e. subjected to high sediment load, higher chlorophyll α concentrations, turbidity etc.) and offshore (i.e. less exposed). The corals were exposed in the lab to gradually increasing temperatures (25.5–33.5 °C) for 72 h after which they were allowed to recover to ambient temperature (25.5 °C) for 24 h. Production and respiration were measured after 24, 48, 72 and 96 h. The results show that P. lutea from nearshore reefs suffered an initial decrease in gross primary production/respiration (GP/R) ratio after 24 h, after only a moderate temperature increase (+2 °C, from 25.5 to 27.5 °C), while there was no difference in GP/R ratio between heat-exposed and controls the other days, indicating that the chronic disturbance in the nearshore reef had no effect on their thermotolerance. Furthermore, P. lutea from the offshore reef showed a decrease in GP/R ratio both after 24 h and 72 h (33.5 °C) of exposure. In comparison, G. fascicularis showed a decrease in GP/R ratio after 48 h, 72 h and 96 h of exposure for the nearshore corals. Also, after 72 h these corals had withdrawn their polyps. There were no differences between heat-treated and controls for the offshore G. fascicularis. This implies that the chronically disturbed G. fascicularis had lower thermotolerance when exposed to a temperature increase. This study, hence, shows that the response of corals to elevated seawater temperature varies with species and environmental background history. ► Chronically disturbed Galaxea fascicularis respond negatively to temperature increase. ► Porites lutea not more affected by elevated temperature when chronically stressed. ► Temperature increase affects even coral species from the same area differently
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0141-1136 1879-0291 1879-0291
DOI:	10.1016/j.marenvres.2011.01.007