[Coral-List] bleaching on the Great Barrier Reef

Dennis Hubbard dennis.hubbard at oberlin.edu
Thu Apr 2 14:07:44 UTC 2020


Thanks for keeping us updated on all of ths. A question to anyone who works
on the genetic side of  things.... is there any evidence that a strain of
zoox exists that is more thermally tolerant and could eventually start to
"adjust" to a warmer world and resolve these problems on our own. I enjoy
learning from everyone's posts and hope they will keep coming  - but, the
likelihood is that it's not going to get any cooler any time soon. This may
be the grand experiment we've always wished for and are, unfortunately,
getting. On a longer scale, remember that this is not the first time this
has happened. In the Cretaceous, it warmed so much that corals were
displaced in the core tropics by rudists, super-molluscs that would make
*Tridacna* look like limpets. The corals simply moved latitudinally, I
believe more along the northern tropical boundary than the southern one
(this may have been controlled by shelf availability and the relative
importance of land vs water in the two hemispheres.

The good news is that this ended at the K-T boundary when things cooled
abruptly. The bad news is that the driver was a huge bolide crashing
somewhere in the Yucatan and vaporizing a large quantity of water. The
combined vapor and ash cooled things quickly and many species (even genera)
just disappeared. The take-home message may be that *Homo stupidus* is the
equivalent of that bolide, just on the scale of pulling the bandade off
very slowly.

Sorry for the long response, but there isn't much else to do here with the
Covid shutdown. To end on a real morose note, maybe Covid is the next
bolide, If so, the natural system will probably reset a lot quicker than at
the KT boundary. We still have an intact atmosphere and reductions  in
atmospheric emissions are already occurring at a scale that our
instrumentation is able to detect it. If nothing else, it shows that enough
individual reductions in a "normal lifestyle" can make a difference.

To finish with a bridge between geologic and human time scales, the most
drastic climate change that we know of is the PETM - the Paleocene Eocene
Thermal Maximum. At that time, the climate of northern California moved
north into southern Alaska at a rate on the scale of several generations -
that's geologically instantaneous. We know this because of careful studies
of preserved leaves. The big question has been what causes the MAJOR jump
in temperature over such a short timeframe. The most likely answer is the
melting of methane clathrates. These are huge deposits of methane - and in
the case of the PETM the thought is that these were submarine (what Conrad
Neuman referred to a "sea farts"). The main source of these now is in
sub-glacial tundra that are being exposed as glaciers melt. So, at some
point, when these melt quickly enough we won't be arguing over local versus
global options. We need to change NOW. As much as I would miss the personal
contact of the ICRS meeting, this may be a message that we can't ignore.
For those that will argue "I told you so", I've been listening. However, we
might start thinking about how much our "incredibly important" research
trips are really as important as we think. The problem is where do we
balance the carbon emitted by a particular research project and the lost
knowledge that might be the answer to the new "coral reef problem". Today's
pop quiz - does anyone out there know where this term originally comes
from?. Submit your answers to the liat serve - we all have a lot of time on
our hands if we are practicing social distancing like we should.





timing - Rudists

On Wed, Apr 1, 2020 at 9:14 AM Douglas Fenner via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Another popular article:
> Climate crisis may have pushed world's tropical coral reefs to tipping
> point of 'near-annual' beaching
> https://www.theguardian.com/environment/2020/apr/01/climate-crisis-may-have-pushed-worlds-tropical-coral-reefs-to-tipping-point-of-near-annual-bleaching?CMP=share_btn_fb&fbclid=IwAR3O6ZrnzG9FPTyNUPJrusQc-qtXSu5-R7XqEfEX-WHpaVqy4yU-r3-I9Do
> Open-access
> Cheers, Doug
> --
> Douglas Fenner
> Lynker Technologies, LLC, Contractor
> NOAA Fisheries Service
> Pacific Islands Regional Office
> Honolulu
> and:
> Consultant
> PO Box 7390
> Pago Pago, American Samoa 96799  USA
> "Already, more people die  <http://www.nws.noaa.gov/om/hazstats.shtml>from
> heat-related causes in the U.S. than from all other extreme weather
> events."
> https://www.npr.org/2018/07/09/624643780/phoenix-tries-to-reverse-its-silent-storm-of-heat-deaths
> Even 50-year old climate models correctly predicted global warmng
> https://www.sciencemag.org/news/2019/12/even-50-year-old-climate-models-correctly-predicted-global-warming?utm_campaign=news_weekly_2019-12-06&et_rid=17045989&et_cid=3113276
> "Global warming is manifestly the foremost current threat to coral reefs,
> and must be addressed by the global community if reefs as we know them will
> have any chance to persist."  Williams et al, 2019, Frontiers in Marine
> Science
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Dennis Hubbard
Chair, Dept of Geology-Oberlin College Oberlin OH 44074
(440) 775-8346

* "When you get on the wrong train.... every stop is the wrong stop"*
 Benjamin Stein: "*Ludes, A Ballad of the Drug and the Dream*"

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