English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

In Situ Oxygen Dynamics in Coral-Algal Interactions

MPS-Authors
/persons/resource/persons210838

Wangpraseurt,  D.
Permanent Research Group Microsensor, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210847

Weber,  Miriam
Permanent Research Group Microsensor, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210728

Røy,  H.
HGF MPG Joint Research Group for Deep Sea Ecology & Technology, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210683

Polerecky,  L.
Permanent Research Group Microsensor, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210257

de Beer,  D.
Permanent Research Group Microsensor, Max Planck Institute for Marine Microbiology, Max Planck Society;

External Resource
No external resources are shared
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)

Weber12.PDF
(Publisher version), 2MB

Supplementary Material (public)
There is no public supplementary material available
Citation

Wangpraseurt, D., Weber, M., Røy, H., Polerecky, L., de Beer, D., Suharsono, S., et al. (2012). In Situ Oxygen Dynamics in Coral-Algal Interactions. PLoS One, 7(2): e31192.


Cite as: https://hdl.handle.net/21.11116/0000-0001-C883-9
Abstract
Background

Coral reefs degrade globally at an alarming rate, with benthic algae often replacing corals. However, the extent to which benthic algae contribute to coral mortality, and the potential mechanisms involved, remain disputed. Recent laboratory studies suggested that algae kill corals by inducing hypoxia on the coral surface, through stimulated microbial respiration.
Methods/Findings

We examined the main premise of this hypothesis by measuring in situ oxygen microenvironments at the contact interface between the massive coral Porites spp. and turf algae, and between Porites spp. and crustose coralline algae (CCA). Oxygen levels at the interface were similar to healthy coral tissue and ranged between 300–400 µM during the day. At night, the interface was hypoxic (∼70 µM) in coral-turf interactions and close to anoxic (∼2 µM) in coral-CCA interactions, but these values were not significantly different from healthy tissue. The diffusive boundary layer (DBL) was about three times thicker at the interface than above healthy tissue, due to a depression in the local topography. A numerical model, developed to analyze the oxygen profiles above the irregular interface, revealed strongly reduced net photosynthesis and dark respiration rates at the coral-algal interface compared to unaffected tissue during the day and at night, respectively.
Conclusions/Significance

Our results showed that hypoxia was not a consistent feature in the microenvironment of the coral-algal interface under in situ conditions. Therefore, hypoxia alone is unlikely to be the cause of coral mortality. Due to the modified topography, the interaction zone is distinguished by a thicker diffusive boundary layer, which limits the local metabolic activity and likely promotes accumulation of potentially harmful metabolic products (e.g., allelochemicals and protons). Our study highlights the importance of mass transfer phenomena and the need for direct in situ measurements of microenvironmental conditions in studies on coral stress.