Visualization of oxygen distribution patterns caused by coral and algae

PeerJ. 2013 Jul 16:1:e106. doi: 10.7717/peerj.106. Print 2013.


Planar optodes were used to visualize oxygen distribution patterns associated with a coral reef associated green algae (Chaetomorpha sp.) and a hermatypic coral (Favia sp.) separately, as standalone organisms, and placed in close proximity mimicking coral-algal interactions. Oxygen patterns were assessed in light and dark conditions and under varying flow regimes. The images show discrete high oxygen concentration regions above the organisms during lighted periods and low oxygen in the dark. Size and orientation of these areas were dependent on flow regime. For corals and algae in close proximity the 2D optodes show areas of extremely low oxygen concentration at the interaction interfaces under both dark (18.4 ± 7.7 µmol O2 L(- 1)) and daylight (97.9 ± 27.5 µmol O2 L(- 1)) conditions. These images present the first two-dimensional visualization of oxygen gradients generated by benthic reef algae and corals under varying flow conditions and provide a 2D depiction of previously observed hypoxic zones at coral algae interfaces. This approach allows for visualization of locally confined, distinctive alterations of oxygen concentrations facilitated by benthic organisms and provides compelling evidence for hypoxic conditions at coral-algae interaction zones.

Keywords: Algae; Coral; Dissolved oxygen; Interaction; Planar optode; Two dimensional visualization.

Grants and funding

Funding for this study was provided by the National Science Foundation to Principal Investigators JES (NSF Grant No. OCE-0927448) and FR (NSF Grant No. OCE-0927448 OCE-0927415 and DEB-1046413). Additional funding was provided by CAPES-FIPSE and Rede Abrolhos (SISBIOTA/CAPES, CNPq, FAPES), Brazil. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.