[Coral-List] New paper in GCB on a standardized short-term thermal assay/platform to detect coral bleaching thresholds

[Daniel Barshis]

Dear Coral-Listers,
      I would like to share with you a new article from a collaboration
between my lab and that of Christian Voolstra that just came out entitled
"Standardized short‐term acute heat stress assays resolve historical
differences in coral thermotolerance across microhabitat reef sites". The
article is available free/open access at the following link (
https://onlinelibrary.wiley.com/doi/10.1111/gcb.15148).
     In this study, we present the CBASS (Coral Bleaching Automated Stress
System) as a platform/approach capable of delivering a standardized, rapid
experimental exposure to assess coral thermal thresholds. We hope that this
technology/approach can be refined and utilized by other research groups in
an effort to develop a consistent experimental diagnostic for
cross-comparison of data across studies. The abstract is pasted below and
feel free to reach out to Christian or I if you have any questions.
Cheers,
dan

Abstract:
Coral bleaching is one of the main drivers of reef degradation. Most corals
bleach and suffer mortality at just 1–2°C above their maximum monthly mean
temperatures, but some species and genotypes resist or recover better than
others. Here, we conducted a series of 18‐hr short‐term acute heat stress
assays side‐by‐side with a 21‐day long‐term heat stress experiment to
assess the ability of both approaches to resolve coral thermotolerance
differences reflective of in situ reef temperature thresholds. Using a
suite of physiological parameters (photosynthetic efficiency, coral
whitening, chlorophyll a , host protein, algal symbiont counts, and algal
type association), we assessed bleaching susceptibility of Stylophora
pistillata colonies from the windward/exposed and leeward/protected sites
of a nearshore coral reef in the central Red Sea, which had previously
shown differential mortality during a natural bleaching event.
Photosynthetic efficiency was most indicative of the expected higher
thermal tolerance in corals from the protected reef site, denoted by an
increased retention of dark‐adapted maximum quantum yields at higher
temperatures. These differences were resolved using both experimental
setups, as corroborated by a positive linear relationship, not observed for
the other parameters. Notably, short‐term acute heat stress assays resolved
per‐colony (genotype) differences that may have been masked by acclimation
effects in the long‐term experiment. Using our newly developed portable
experimental system termed the Coral Bleaching Automated Stress System
(CBASS), we thus highlight the potential of mobile, standardized short‐term
acute heat stress assays to resolve fine‐scale differences in coral
thermotolerance. Accordingly, such a system may be suitable for large‐scale
determination and complement existing approaches to identify resilient
genotypes/reefs for downstream experimental examination and prioritization
of reef sites for conservation/restoration. Development of such a framework
is consistent with the recommendations of the National Academy of Sciences
and the Reef Restoration and Adaptation Program committees for new
intervention and restoration strategies.

-- 

  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