Effects of increased heat on fluorescence and dinoflagellate density in the captive coral, Anthelia sp.
- Published
- Accepted
- Subject Areas
- Conservation Biology, Marine Biology, Climate Change Biology
- Keywords
- Coral Bleaching, Global Warming, Dinoflagellates, Fluorescence, Mitotic Index
- Copyright
- © 2019 Santos et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2019. Effects of increased heat on fluorescence and dinoflagellate density in the captive coral, Anthelia sp. PeerJ Preprints 7:e27566v1 https://doi.org/10.7287/peerj.preprints.27566v1
Abstract
The obligate mutualistic relationship between corals and dinoflagellates is a classic example of symbiosis. Coral reefs have been devastated by warm water temperatures at a rapid pace and currently, there is no effective method to predict a mass bleaching event. Fluorescence is a potential indicator of coral health but very few studies have attempted to utilize it as a proxy for dinoflagellate density, which was the scope of the present research. Here, we determined the effects of elevated water temperatures on fluorescence, dinoflagellate density, and mitotic index in the captive coral, Anthelia sp. Over a six-week period, tanks filled with Anthelia sp. underwent gradual increases in water temperature beginning at 28ºC and ending at 34ºC . Coral samples were quantified for fluorescence, dinoflagellate density, and mitotic index by fluorescence microscopy of whole specimens and a maceration method to examine dinoflagellates. As a result of the gradual increase in water temperature, corrected fluorescence decreased over time. In contrast, dinoflagellate density first increased until reaching a thermal limit that was then followed by a decrease. This was driven by an increase in the rate of cell division before the limit and a decrease afterwards. These results suggest that symbionts may be increasing their mitotic rate in response to elevated water temperatures to compensate for the shortage of photosynthate supply for their host. Because fluorescence dropped simultaneously with the increase in dinoflagellate density and mitotic index, coral fluorescence may be utilized as a prognostic tool for coral bleaching in Anthelia sp.
Author Comment
This is a submission to PeerJ for review.