[Coral-List] new paper comparing short-term stress assays to longer-term experiments in Red Sea

[Daniel Barshis]

Hi Folks,
    A new paper of ours comparing the consistency in response between a
short-term, 18hr stress assay and a longer term (7-11 day) experiment in
Gulf of Aqaba corals might be of interest. We also introduce the Fv/Fm
effective dose 50 as a quantitative, experimentally-derived thermal
threshold calculation. Open access at Limnology and Oceanography and
abstract below.
https://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lno.11715

Remarkably high and consistent tolerance of a Red Sea coral to acute and
chronic thermal stress exposures

Abstract
Global warming is resulting in unprecedented levels of coral mortality due
to mass bleaching events and, more recently, marine heatwaves, where rapid
increases in seawater temperature cause mortality within days. Here, we
compare the response of a ubiquitous scleractinian coral, *Stylophora
pistillata*, from the northern Red Sea to acute (7 h) and chronic (7–11 d)
thermal stress events that include temperature treatments of 27°C (i.e.,
the local maximum monthly mean), 29.5°C, 32°C, and 34.5°C, and assess
recovery of the corals following exposure. Overall, *S. pistillata *exhibited
remarkably similar responses to acute and chronic thermal stress,
responding primarily to the temperature treatment rather than duration or
heating rate. Additionally, corals displayed an exceptionally high thermal
tolerance, maintaining their physiological performance and suffering little
to no loss of algal symbionts or chlorophyll a up to 32°C, before the host
suffered from rapid tissue necrosis and mortality at 34.5°C. While there
was some variability in physiological response metrics, photosynthetic
efficiency measurements (i.e., maximum quantum yield Fv/Fm) accurately
reflected the overall physiological response patterns, with these
measurements used to produce the Fv/Fm effective dose (ED50) metric as a
proxy for the thermal tolerance of corals. This approach produced similar
ED50 values for the acute and chronic experiments (34.47°C vs. 33.81°C),
highlighting the potential for acute thermal assays with measurements of
Fv/Fm as a systematic and standardized approach to quantitatively compare
the upper thermal limits of reef‐building corals using a portable
experimental system.

Cheers,
dan

-- 

  Daniel Barshis, Ph.D.
  Associate Professor
  Department of Biological Sciences
  Old Dominion University
  Mills Godwin Building 302J
  Norfolk, VA 23529
  Office: 757-683-3614
  Lab: 757-683-5755
  Web: www.odu.edu/~dbarshis

Schedule an online meeting with me
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