[Coral-List] Identifying bleaching resistant reef locations: is it possible?

[Scott Wooldridge]

Hi All,


I have read with great interest the recent discussions on bleaching
refuges. In contribution to this discussion, I have attached x2
provisionally accepted articles that expand on these issues. Specifically,
I provide important new insight into why some reef locations exhibit lower
(or higher) resistance to thermal bleaching. Such information is crucial,
since for as great as the NOAA SST products are, they are unable to
delineate these important/informative sites in their predictions.


I have developed a new bleaching prediction tool ‘BleachRisk’, which
utilises the NOAA DHW products, but also includes additional drivers of
reef-scale bleaching sensitivity (viz. thermal history, water quality and
solar radiation).  For the GBR, BleachRisk predicts with >85% accuracy
compared with the ~60% of the DHW product alone. Indeed, for the current
2016 coral bleaching event on the GBR it predicts at >95%.


Perhaps of greatest importance, however, I have also utilised the
BleachRisk modelling framework to identify routinely monitored coral health
attributes, such as the tissue energy reserves and skeletal growth
characteristics (viz. density and extension rates) that correlate with
bleaching resistant reef locations.  The x2 manuscripts explain how
bleaching resistant reefs can be readily identified by characteristic coral
health signatures that exist outside of thermal stress conditions, thereby
providing a rational means by which every reef site on the GBR (and
elsewhere) could be ‘field-ranked’ in terms of coral health and thermal
bleaching sensitivity *a priori*. Such information is of considerable value
to local policy-makers and reef managers as it could be used to: (i) guide
the process of prioritizing enhanced protection of bleaching-resistant reef
areas, and (ii) monitoring the benefit of catchment-specific water quality
improvement strategies that seek to increase reef-scale coral health and
bleaching resistance.


Please note, it is not my intention to be at all critical of the NOAA heat
stress products in this research – indeed I think they are excellent
products. It is just (as we all know) that bleaching sensitivity to thermal
stress varies across reefs and regions, and that in the end it is
understanding the reasons for why it varies that is the most crucial issue
for coral reef management. I hope people find these contributions useful to
that task.

Here is the links to the manuscripts:


https://www.researchgate.net/publication/299534164_Excess_seawater_nutrients_enlarged_algal_symbiont_densities_and_bleaching_sensitive_reef_locations_1_Identifying_thresholds_of_concern_for_the_Great_Barrier_Reef_Australia?ev=prf_pub



https://www.researchgate.net/publication/299939163_Excess_seawater_nutrients_enlarged_algal_symbiont_densities_and_bleaching_sensitive_reef_locations_2_A_regional-scale_predictive_model_for_the_Great_Barrier_Reef_Australia




Scott Wooldridge


Catchment to Reef Management Solutions Ltd, Newcastle, Australia 2280