[Coral-List] relatively new article

Sun Feb 27 23:56:32 UTC 2022

I just became aware of another article on the topic of
mesophotic ecosystems and the deep refuge hypothesis.

https://royalsocietypublishing.org/doi/10.1098/rspb.2018.1987

This is probably not open-access.  Click on first author name to find email
address.

Cheers, Doug

On Sun, Feb 27, 2022 at 11:32 AM Douglas Fenner <
douglasfennertassi at gmail.com> wrote:

>       The article I posted about actually says that there is minimal
> overlap in the coral species in American Samoa between the coral reef above
> 30 m deep and the mesophotic reef.  That means there is a limited
> opportunity for an effective deep refuge for corals here, even if all the
> other things were in place to make it possible, such as larvae from deep
> arriving in shallow to replace dead shallow colonies, deep coral genetics
> that allows those their larvae to survive and grow in shallow water, and
> maybe a few other things.
>       Yes, I was reading that the US east coast had much more rapidly
> rising sea levels than elsewhere.  Notice that all the sea level graphs the
> article Mike points us to are from the US east coast and Gulf coast.  I
> believe that rise has to be because at some depth in that area, water has
> warmed, which I presume would have to be due to the sinking of water that
> was warmer than has been sinking in the past (the sun only heats the
> surface of the water).  Most of the water that sinks to the deep sea is in
> Antarctica and in the north Atlantic, I believe.  Water expands very
> slightly when it warms.  So strange as it may seem, locally slightly warmer
> deep water can cause faster local rises than the global average (a local
> sea surface bulge).  Or maybe currents are pushing the water higher.  Last
> I knew, the average global sea level rise rate was up from 3 mm/yr to about
> 4.5 mm/yr.  Well within the range of growth rates for coral reefs.  Most of
> the world's coral reefs are not on the US east coast, in fact the only ones
> on the US east coast are at the far southern end at the southern tip of
> Florida.  And the US Gulf Coast has precious few reefs.  Most of the
> world's reefs are far from that, in places like the Coral Triangle and the
> Pacific Ocean.
>        Clearly, the rate of sea-level rise is increasing, and it is
> certain to accelerate in the future.  Exactly how fast it will go is a
> difficult thing to predict, much of the ice in a place like the West
> Antarctic may, or may not, start sliding off faster if the Thwaites glacier
> becomes ungrounded where it floats as an ice sheet, or simply having the
> ice sheet break off will let it start sliding off much faster.  It won't
> slide off in a flash, but the rate of sliding off could go up
> significantly, and surely will at some point in the future, but maybe not
> very soon, hard to predict they say.  But the science is surely getting
> better all the time.
>        So over the longer period of time, you're surely right.  Over
> shorter time spans it is much more open.  Over a couple decades, I doubt
> sea level rise is going to outpace the growth of many coral reefs.  And
> when it does, it will simply provide more accommodation space, that is,
> water above it, that coral can grow into.  Even at 4.5 mm a year, with
> staghorns and tables able to grow 100 mm a year and massive corals able to
> grow around 10 mm a year, most corals can grow as fast or faster than
> sea-level rise.  Because corals don't cover the entire surface of the reef,
> the reef can't grow as fast as the corals.  But if the sea level rise would
> just hurry up, corals could grow much more on reef flats and have higher
> coral cover and thus reef flats could grow upward faster than they do now
> (but only where there isn't heavy terrestrial sediment).  Reef flats
> typically have low coral cover, boosting it to high coral cover would speed
> reef growth rate.  If global warming and bleaching didn't kill corals, it
> would benefit most of the world's reefs, reef flats would have higher coral
> cover since the lowest tides of the year wouldn't be killing the coral, and
> with higher coral cover, the reef itself could grow upward faster (and more
> live coral on the reef flat would reduce shoreline erosion).  Sadly, we
> won't see that because global warming-produced bleaching is going to kill
> most of the corals before the water gets deep enough to make much of any
> difference.
>       Sea level rise relative to land in American Samoa is currently going
> faster than the world average as well.  This is because the 2009 earthquake
> south of us near the Tonga Trench released stresses that were helping to
> hold American Samoa about 40 cm higher than it would otherwise be.
> Immediately after the earthquake the islands began to subside, and so far
> they've gone down about 20 cm if I remember, and this should slow down and
> stop at about 40 cm drop, it is predicted.  But if I go out on the reef
> flats, I can't tell the difference.  It sure doesn't look to me like there
> is 20 cm more water on the reef flats here currently.  Sea level rise has
> to go faster than that to get ahead of the corals.
>      Of course, when (it is not "if" it is "when") mass coral bleaching
> kills most of the corals, as it is predicted to start doing in 2-3 decades,
> then the reefs will not be able to grow much faster than crustose coralline
> algae, maybe around 1 mm a year and game over, sea level rise wins and
> corals and humanity loses.  But note, corals lose because of mass coral
> bleaching, and the reef geological structures will still be there.  Even
> coralline algae will lose, global warming is much less likely to kill it
> than corals, but it is more sensitive to acidification than corals.  Seems
> inevitable, sooner or later.
>       And of course, the geological reef structures will still be there
> and barely any deeper than they were before.  Corals can grow well down to
> around 30 m deep, some much deeper.  Sea level rise would have to be 30 m
> before all reefs would be drowned below the level at which if there are
> living corals, they can continue to grow the reef structure.  At 10 mm/yr
> sea level rise, that would take 3000 yrs to reach a total of 30 m sea-level
> rise.  My understanding is that even if we stop emitting all greenhouse
> gases tomorrow. sea-level rise will not only continue, it will continue to
> accelerate for some time to come, and sea-level rise will continue for
> millennia.  Because the world is warmer.  To stop that from happening would
> require removing CO2 from the atmosphere.  Trees and other plants are very
> good at doing that, but humans are very good at causing deforestation and
> not leaving the carbon sequestered in the wood.  Surfaces of rocks exposed
> to air for the first time, typically where erosion is happening rapidly,
> WILL eventually stabilize CO2, I've been led to believe.  But that
> will/would take more than millennia, maybe millions of years (?)
>      So, if humanity were to get its act together and stop emitting CO2
> and allow forests and other plant life to sequester carbon, global warming
> could stop and temperatures could even start to come down and sea-level
> rise slow.  IF (IF!!) coral species haven't been driven to extinction, then
> they could start to repopulate those geological reef structures and rebuild
> coral reef ecosystems.  It's a dream, not impossible, but given what a
> lousy job humanity is doing so far, sure seems like a pipe dream to me.  As
> one line in the musical/movie "South Pacific" put it, "if you no got a
> dream, how you gonna have a dream come true?"
>      But for the foreseeable future, I agree with you.   Cheers, Doug
>
>
>
> On Sat, Feb 26, 2022 at 8:45 AM Risk, Michael <riskmj at mcmaster.ca> wrote:
>
>> Not going to happen, Doug. Sea level rise, now 11mm/yr, is already above
>> the ability of reefs to keep up. Bandaids won't suffice.
>> https://tamino.wordpress.com/2022/02/23/sea-level-denial/
>> <https://tamino.wordpress.com/2022/02/23/sea-level-denial/>
>> Sea Level Denial | Open Mind
>> <https://tamino.wordpress.com/2022/02/23/sea-level-denial/>
>> Back in 2010, the North Carolina's Coastal Resource Commission published
>> the North Carolina Sea Level Rise Assessment Report. Dave Burton of "NC-20"
>> (a trade group for business interests in the coastal counties of NC)
>> ridiculed their results, claiming that the only sensible way to forecast
>> future sea level rise was to fit a straight line…
>> tamino.wordpress.com
>>
>> ------------------------------
>> *From:* Coral-List <coral-list-bounces at coral.aoml.noaa.gov> on behalf of
>> Douglas Fenner via Coral-List <coral-list at coral.aoml.noaa.gov>
>> *Sent:* Saturday, February 26, 2022 2:37 AM
>> *To:* coral list <coral-list at coral.aoml.noaa.gov>
>> *Subject:* [Coral-List] relatively new article
>>
>> deep reef refuge hypothesis
>>
>> https://www.nature.com/articles/s41598-021-03128-8
>>
>> Open-access
>>
>> Cheers, Doug
>>
>> --
>> Douglas Fenner
>> Lynker Technologies, LLC, Contractor
>> NOAA Fisheries Service
>> Pacific Islands Regional Office
>> Honolulu
>> and:
>> Coral Reef Consulting
>> PO Box 997390
>> Pago Pago, American Samoa 96799-6298  USA
>>
>> Over 1 million sq km more land cleared for crops
>>
>> https://www.science.org/content/article/cropland-has-gobbled-over-1-million-square-kilometers-earth-s-surface
>>
>> Peat bogs hold TWICE as much carbon as the world's forests!!!
>>
>> https://www.yahoo.com/news/environmentalists-fight-protect-peat-bogs-233902101.html
>>
>> Slashing emissions by 2050 isn't enough.  We can bring temperatures down
>> now.
>>
>> https://www.washingtonpost.com/outlook/climate-deadlines-super-pollutants-hfcs-methane/2021/04/15/acb8c612-9d7d-11eb-b7a8-014b14aeb9e4_story.html
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>