[Coral-List] Nutrients / coral bleaching / coral mortality / coral disease

[Rebecca Vega Thurber]

Hi everyone. Exciting and informative discussion.

Since Scott brought it up, I'd also like to comment on some additional work
we have done with Deron Burkepile's lab where we have examined the
interactive effects nutrients with temperature in the field.

>From that same experiment that Scott mentioned, where we continuously
enriched replicated plots in the Florida Keys for 3 years, we also showed
that chronic nutrient enrichment significantly increased coral *mortality*, not
just disease and bleaching as the *Global Change Biology *paper showed.
However, we also found that a majority of that mortality in the nutrient
enriched areas was concentrated in the warmest times of year. This finding
was presented in our open access 2016 *Nature Communications* paper,
aptly entitled, "Overfishing and nutrient pollution interact with
temperature to disrupt coral reefs down to microbial scales."
https://www.nature.com/articles/ncomms11833  Interestingly this work also
shows that nutrients likely act to reduce coral health by a variety of
mechanisms.

Further, an important consideration of this past work was that, generally,
thermal stress was low during the years we conducted that long term
experiment (2009-2012). However we've continued doing these kinds of
experiments and found different results when thermal stress was high.

We recently published a paper in *Frontiers of Marine Science* showing,
that during the 2014 bleaching event in the Florida Keys, nutrients alone
did *not *increase the prevalence and severity of disease or bleaching
above back ground levels because temperature had such a large effect alone.
Disease and bleaching dramatically rose in all cases. However, nutrients
did, to some degree, prolonged bleaching in some coral species. Further,
elevated nutrients had a distinct effect on coral microbiomes that was
independent of temperature. So basically the story about nutrients and
temperature is more complicated than we originally thought.  Here is the
link to that paper if you are interested.
"Corals and their microbomes are differentially affected by exposure to
elevated nutrients and a natural thermal anomaly."
https://www.frontiersin.org/articles/10.3389/fmars.2018.00101/full

 -Becky


-- 
Dr. Rebecca Vega Thurber
Associate Professor of Microbiology
Oregon State University
454 Nash Hall
Corvallis OR  97331-3804, U.S.A
541-737-1851 (office) 541-737-0496 (FAX)
rvegathurber at gmail.com;Rebecca.Vega-Thurber at oregonstate.edu
<Rebecca.Vega.Thurber at oregonstate.edu>