[Coral-List] Photographic method to analyze bleached coral fragments

Daniel Wangpraseurt wangpraseurt at googlemail.com
Tue Feb 12 15:48:39 UTC 2019

Dear Sofia,

If the images are calibrated against a reflectance standard, then it is
possible to approximate the whiteness of the coral fragment. This is very
easy to do in Matlab or imageJ. However, how such relative whiteness
relates to symbiont cell density and chlorophyll a content is a more tricky
subject and will be affected by the optical properties of the corals
(including host pigments, light scattering etc.). There are simple and
widely used approaches such the color reference card by Siebeck et al.
Also see Winters et al., 2009 (https://doi.org/10.1016/j.jembe.2009.09.004)
for a more in-depth discussion of the topic.

Hope this helps.


Dr. Daniel Wangpraseurt
Marie Curie Fellow
University of Cambridge & Scripps Institution of Oceanography

3430 Hubbs Hall,
Scripps Institution of Oceanography,
University of California San Diego,
8750 Biological Grade,
La Jolla, CA 92037

phone: +1-619-381-8978
researchgate <https://www.researchgate.net/profile/Daniel_Wangpraseurt>

On Tue, Feb 12, 2019 at 2:37 PM Sofía Lorda Dumont via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Hello everyone,
> I hope you are well. I would like to ask you if you know of any method to
> analyze photos of coral fragments. These fragments were placed in tanks and
> were exposed to different temperatures to see how their color changed over
> time. Is there a particular software you recommend? Also, do you know of
> any recent references that could include this information? Or something
> relevant to thermotolerance and coral mortality?
> Many thanks.
> Best,
> Sofia
> *Ana Sofía Lorda*
> *MSc student in Biodiversity, Conservation, and Management*
> *School of Geography and the Environment (SoGE)*
> *University of Oxford *
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