[Coral-List] Coral on the Great Barrier Reef was 'cooked' during 2016 marine heatwave. REALLY? REALLY? REALLY?

[Scott Wooldridge]

Dear Coral Listers,


I draw your attention to a press release/article describing the findings
from the recent Hughes et al. (2018) Nature paper describing the Great
Barrier Reef (GBR) coral bleaching event in the austral summer of 2015/16.


http://www.abc.net.au/news/2018-04-19/marine-heatwave-so-bad-it-cooked-parts-of-great-barrier-reef/9667518


Now I am all for making the public aware of the dire situation coral reefs
face during the Antropocene. And maybe such reporting of the results is
good enough for the general public. But it is certainly NOT good enough for
scientists, coral reef managers or policy makers.


Indeed, it is my personal opinion that the entire reporting of the 2015/16
coral bleaching event in the previously pristine far northern GBR has been
rather misleading - with a single-minded preoccupation with sensationalism
and media grab bites rather than the pursuit of science that increases our
ability to help save coral reefs into the future.


Lets consider the facts for the 2015/16 coral bleaching event, wherein the
corals supposedly 'cooked' like crabs in a boiling pot of water. Would it
surprise people to know that the corals SEVERELY bleached at surface
heating levels less than 3-4 degree heating weeks. Such low heating levels
usually only warrant a precautionary warning from NOAA (i.e. level 1 on a 4
level scale) Would it also surprise people to know that the same far
northern reefs experienced heating levels in excess of 8-10 degree heat
weeks stress (highest level on NOAA 4-level scale) in the austral summer of
2008/09, yet NO bleaching was recorded despite extensive regional searches
from dedicated cruises?


See here for a comparison of the heating stress in 2008/09 and 2015/16.


https://www.researchgate.net/publication/324644910_Comparison_of_heat_stress_in_the_northern_GBR_for_201516_and_200809



I remember in great detail the 2008/09 situation because I helped plan cruise
trips to search for coral bleaching based on the NOAA heat stress maps. We
fully expected to observe severe bleaching, as evidenced by the media
reporting of the day. But we found nothing (zero bleaching)


Claims that the corals 'cooked' in 2015/16 are quite simply absurd and show
a complete lack of understanding of the eitology of natural coral
bleaching. Rather than a preoccupation with sensationalism and media grab
bites, the key question driving the data analysis of the 2015/16 bleaching
event should be, 'why such high bleaching sensitivity at low thermal
stress?' or reposed differently 'why such low sensitivity to high thermal
stress in 2008/09?' And overarching all this, 'what does this mean for
managing the GBR?', i.e. what can we learn from these 2-events that helps
provide managers with new levers to increase the 'resistance' of corals to
warming sea temperatures.


In my next post, I will offer some personal insight into the above
questions.


These are important times for coral reef research. We need to recommit to
good science. We need to ignore sensationalism at all costs. Corals did not
'cook' on the far northern GBR in 2015/16. In fact they severely bleached
at temperatures which are not normally associated with mass bleaching
events. This is significant and should be clear and evident to all. Indeed,
this fact holds the key to the survival (or not) of coral reefs into the
future.


Scott


https://www.researchgate.net/profile/Scott_Wooldridge