[Coral-List] Thoughts on coral decline and the future.
riskmj at mcmaster.ca
Fri May 12 19:51:22 EDT 2017
Thank you for your response. I have no answers, just a basketfull of
concerns. I wonder if my grandchildren (3, so far) will ever see anything
like the reefs that I have seen.
I would question your assertion that global changes have already outstripped
land-based stresses. Yes, we hear depressing stories of bleaching. Right
now, we do not know what the pace of recovery will be. We know that
nutrients slow that recovery (Wooldridge and Done-great to see Terry still
trucking along). Michael Schleyer, a good friend of mine and a top scientist
working in difficult conditions, recently emailed me (Mike, hope quoting you
is OK-too late now!) “I have had the good fortune of visiting remote reefs
such as the Chagos, Glorieuses and Europa and, while they have all been
whacked by bleaching, their recovery has been remarkable.” I would also
direct you to his excellent new paper, Porter and Schleyer 2017 (DOI
10.1007/s00338-016-1531-z.) This describes another set of reefs on a
downward trajectory off the coast of South Africa-but in this case, the
water temperature went down, not up. Mike tells me he had an awful time
getting this accepted, which given the mindset of many coral reef
biologists, I do not doubt for a second.
Another paper that had a difficult delivery is Tomascik et al. 1996 (Coral
Reefs 15: 169). Briefly: a lava flow entered a bay in the Banda Islands, in
eastern Indonesia, with much hissing and boiling. The locals now call that
Hot Water Bay (Air Panas). Five years later, the lava flow had greater than
60% coral cover, with tabulate corals almost a meter in diameter. Tom and
his co-authors (Rob van Woesick and Tom’s wife, Anmarie Mah) had a heckuva
time with this one, because there was great resistance to the idea that
corals could grow so quickly in such a seriously overfished environment. The
answer, of course, is that the water is dead clean, wonderfully clear-close
to the best diving of my life.
Before anyone tries to tell me of widespread death of Indo Pacific reefs
from global change, I would like to be reassured that they had read Tom
Tomascik’s work, and Evan Edinger’s, and had spent some time diving the
beautiful (not) reefs next to Singapore, Hong Kong, Jakarta… You get the
Re dust: I am sure Gene can respond much better than I can. I think he has
an excellent point, and I don’t for the life of me see why so many
biologists refuse to consider it. You are correct, it “works” for the
Caribbean. Previous Caribbean reefs must have faced input of dust and
survived, but-the Sahara is growing, which means the rate of dust production
is going up. And of course there are truly enormous dust storms that come
off the Arabian Plate over into the Gulf.
In short, no matter who “wins” this race, we won’t like the outcome.
Continuing on this depressing vein: the sea level rise we are seeing now is
almost at the limits of upward reef accumulation (read Dennis Hubbard’s
stuff). This rate is basically the calm before the storm. Greenland has yet
to destabilize, although there is meltwater running underneath the ice. Much
of the land ice in Antarctica continues to shrink, but not as yet
catastrophically. The lesson of the past is that, during meltwater-driven
transgressions, rises in sea level can be rapid and episodic. Remember that
Nature paper my wife wrote (urk, 20 years ago) showing that the Gulf Stream
started to shut down in less than 4 years. (My wife is no longer in science.
She told me "there are a lot of nasty people there, and that may include
We really are entering into the unknown, and you are correct: the recent
Syrian refugee problem will look like a flea bite. We need to do the best we
can: set examples in our personal life, and be politically active. And hope.
On May 12, 2017, at 12:18 PM, thomas at seamarc.com wrote:
Thanks for your effort in summing this up.
I read: "There is a large body of research supporting the contention that
land-based stress dominated until late in the 20^th century, but global
warming is gaining quickly in a race we would rather not watch." The lessons
from coral reefs other than the Caribbean is that global has unfortunately
already overtaken the land based stresses. Just like I suppose that the land
based stresses would have overtaken the effects of the dust at some stage,
making it a lesser concern.
Regarding the dust, maybe Gene can tell us has significant the year 83 in
geological terms. If ever such events have happened in the past, I guess the
reefs would have recovered before 83. Why wouldn't the reef have recovered
by now? If such events are more frequent than before, explaining a
continuous decline, are we not talking about an early sign of climate
change? We also need to mention that this is mostly a Caribbean problem as
the dust transport mentioned represents 70 % of the dust movement over the
You also write: "Human populations will be displaced, perhaps suddenly, by
unpredictable rises in sea level. The time may come when society as a whole
may not have the resources to save coral reefs, because people come first".
I am under the impression that the sea level rise is predicted, and even
measured. The question however is, looking at the current situation, by how
many times do we have to multiply the amount of Syrian refugees for the
situation to become unbearable?
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