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Effects of reduced dissolved oxygen concentrations on physiology and fluorescence of hermatypic corals and benthic algae
- Source :
- PeerJ, Vol 2, p e235 (2014), PeerJ, vol 2, iss 1, PeerJ
- Publication Year :
- 2014
- Publisher :
- PeerJ Inc., 2014.
-
Abstract
- While shifts from coral to seaweed dominance have become increasingly common on coral reefs and factors triggering these shifts successively identified, the primary mechanisms involved in coral-algae interactions remain unclear. Amongst various potential mechanisms, algal exudates can mediate increases in microbial activity, leading to localized hypoxic conditions which may cause coral mortality in the direct vicinity. Most of the processes likely causing such algal exudate induced coral mortality have been quantified (e.g., labile organic matter release, increased microbial metabolism, decreased dissolved oxygen availability), yet little is known about how reduced dissolved oxygen concentrations affect competitive dynamics between seaweeds and corals. The goals of this study were to investigate the effects of different levels of oxygen including hypoxic conditions on a common hermatypic coral Acropora yongei and the common green alga Bryopsis pennata. Specifically, we examined how photosynthetic oxygen production, dark and daylight adapted quantum yield, intensity and anatomical distribution of the coral innate fluorescence, and visual estimates of health varied with differing background oxygen conditions. Our results showed that the algae were significantly more tolerant to extremely low oxygen concentrations (2-4 mg L(-1)) than corals. Furthermore corals could tolerate reduced oxygen concentrations, but only until a given threshold determined by a combination of exposure time and concentration. Exceeding this threshold led to rapid loss of coral tissue and mortality. This study concludes that hypoxia may indeed play a significant role, or in some cases may even be the main cause, for coral tissue loss during coral-algae interaction processes.
- Subjects :
- Coral
chemistry.chemical_element
lcsh:Medicine
Marine Biology
Hermatypic coral
Photosynthesis
Oxygen
Medical and Health Sciences
General Biochemistry, Genetics and Molecular Biology
Fluorescence
Algae
natural sciences
14. Life underwater
Hypoxia
Coral-algae competition
geography
geography.geographical_feature_category
Ecology
biology
General Neuroscience
fungi
lcsh:R
Oxygen evolution
technology, industry, and agriculture
Hypoxia (environmental)
General Medicine
Coral reef
Biological Sciences
biochemical phenomena, metabolism, and nutrition
biology.organism_classification
Photobiology
chemistry
General Agricultural and Biological Sciences
geographic locations
Subjects
Details
- Language :
- English
- ISSN :
- 21678359
- Volume :
- 2
- Database :
- OpenAIRE
- Journal :
- PeerJ
- Accession number :
- edsair.doi.dedup.....50a0f69fe1f6e71f6076e4770bedc704