[Coral-List] Bioturbulence Proven as a Factor in Ocean Mixing and it's Implications

Tue May 31 00:20:18 UTC 2022

Pretty much every supposition you make is testable, or at least the
magnitude of its effects can be estimated. You might want to talk to
someone who actually knows something about boundary layers -- like Kurt
Polzin at WHOI -- and see if he might be interested in making some of those
calculations.I personally am not ready to go from the very weak and very
geographically limited conclusions in the original paper you cited to your
hypothesis that lack of fish tails will cause a global collapse of coral
reefs.

- Mel

On Mon, May 30, 2022 at 5:09 PM Austin Bowden-Kerby <abowdenkerby at gmail.com>
wrote:

> Mel, A few more thoughts on bioturbation.
>
> I think that this paper is potentially HUGE in that it shows that
> bioturbation can essentially erase the boundary layers in an ocean, which
> is an important aspect of the wider picture of mixing,
> because boundary layers are known to prevent the broader process of mixing.
> Upwelling for example is suppressed across a strong boundary layer. So I
> wonder what the killing off of vast schools of fish or whales that dwell
> near the thermocline might cause to nutrient fluxes in the wider ocean?
>
> Even a good laminar flow over a coral reef forms a boundary layer around
> corals, which I think that only the fish routinely break.  As far as the
> corals are concerned, I believe that the micro scale (from a few mm to tens
> of centimeters), is where much of the action is, but in the ocean boundary
> layers are hugely important, just saying.  The planet is alive, but
> declining rapidly.  In time they will have this all figured out, if we
> don't collapse the whole system first!  Could bioturbation be similar to
> "death by a million cuts", but rather "life by a million tails"?
>
> Austin
>
> On Tue, May 31, 2022 at 2:50 AM Melbourne Briscoe <mel at briscoe.com> wrote:
>
>> Yes, I've spent hours watching the little fish tails stir things up, in
>> specific locations at specific times. This should not be confused with
>> "ocean mixing," to which the little fish tails are an insignificant
>> contribution in general, just as the original paper Austin cited says.
>> The fish "bioturbulence" (it is not actually turbulence you are
>> describing but rather stirring" probably does have an effect on the corals,
>> but it is an enormous, unjustified, and mathematically impossible stretch
>> to say that this is significant to ocean mixing in general.
>>
>> - Mel
>>
>> On Mon, May 30, 2022 at 10:11 AM Andrew Ross <ross.andrew at mac.com> wrote:
>>
>>> Hi Mel,
>>> It’s pretty common & by no means a deductive stretch. I myself have seen
>>> what Austin is describing - a larger fish hovering over a coral &
>>> displacing parrotfish-poop by “little fish tails” (& other fins). It’s a
>>> question of scale & repetition: fish-fin/movement currents function over a
>>> scale of inches and without calm morning nor seasonal breaks, which is what
>>> the coral needs, particularly in those without a well-developed mucus
>>> cleaning system such as *Acropora*. To this, I’ve also seen mucky dead
>>> spots in the middle of flatter corals in places where there aren’t these
>>> larger fish (overfished), all of this being a regular topic around the
>>> conference bar… so its not just me/us seeing it.
>>>
>>> I might tease about *getting out of the office & out into the sea,* but
>>> I’m watching same right now in my office's cichlid-tank…
>>>
>>> Best regards,
>>>
>>> Andrew M. Ross, Ph.D.
>>> Seascape Caribbean
>>> +1-876-363-8850
>>>
>>>
>>> On May 29, 2022, at 1:32 AM, Austin Bowden-Kerby via Coral-List <
>>> coral-list at coral.aoml.noaa.gov> wrote:
>>>
>>> Hi Mel and all,
>>>
>>> I was just using simple logical deduction: since the study proves that
>>> fish
>>> cause significant ocean mixing, if those same fish are then overfished to
>>> extinction or reduced by half, it only follows that the fish-induced
>>> mixing
>>> caused by that species will stop completely, or be reduced by half
>>> accordingly.  If these fish cause bioturbulence, then imagine how much
>>> better tuna, mackerel, sardines, whales, etc. might be, but especially
>>> those species that cross boundary layers.
>>>
>>> Thanks for sharing the 1860 quote from La Mer "the combined motion of the
>>> little fish tails"...  of course!  Brilliant!
>>> Sadly, the day of descriptive science and assumptions based on logic and
>>> keen observation are presently out of fashion, but I think that they need
>>> to come back, because hypothesis testing and other forms of science that
>>> are in vogue are limited, as they often exclude close visual observations
>>> and detailed descriptions, which is of course due to the fact that few
>>> scientists live on the reef and go out daily or weekly year after year.
>>> Science seems to be moving far too slowly for a system in grave danger of
>>> collapsing.
>>>
>>> Being "on the spectrum", much of what I know is based on reading other
>>> works as well as my own close observation of the systems in both the
>>> Pacific and Caribbean over decades.  Much of what I operate on has never
>>> been published, due to my personal circumstances and limitations, and not
>>> being attached to any academic research institution, having to fight the
>>> wolf at the door on an ongoing basis year after year.  I have developed a
>>> long list of observations and preliminary conclusions that you won't find
>>> in any journal, but as they are based on simple logic, and based on
>>> multiple observations, I am teaching these speculations and observations
>>> to
>>> indigenous marine graduates and others in our course "Coral restoration
>>> for
>>> climate change adaptation", making it clear that they are my own
>>> assumptions and might in time be proven or disguarded.  We welcome
>>> researchers and graduate students to attend one of these workshops, and
>>> to
>>> come to our field sites as interns or researchers, and to work with us,
>>> as
>>> we need verification of many observations and working hypotheses, and
>>> time
>>> is far too short to not share "intellectual property" more openly before
>>> it
>>> is published. Saving the coral reefs should certainly be enough of a
>>> reward- and just imagine how much unpublished knowledge goes to the grave
>>> every year?!
>>>
>>> One example of what I am talking about, and directly related to the topic
>>> of this email thread, is that I have long assumed that fish are vital to
>>> branching corals for oxygenation, nutrient uptake, waste removal, and
>>> sediment removal, not only because it is completely logical, but because
>>> we
>>> see evidence that it is happening.  It is clear from observations of
>>> tabulate Acropora corals versus digitate or staghorn Acropora, that
>>> Chromis
>>> and Dascyllus, both planktivorous fish, make a difference to survival in
>>> challenging lower flow habitats in the IndoPacific:  We observe that
>>> tabulate corals do NOT provide habitat for planktivorous fishes, and so
>>> they generally do poorly in these silty and low-flow situations, while
>>> the digitate and staghorn growth forms do just fine in such low flow
>>> conditions, especially if they are able to attract Chromis and Dascyllus.
>>> On a less definite and more speculative aside, I hypothesize that the
>>> corals might be competing for these little fish, which has in turn
>>> resulted
>>> in diverse and  flamboyant coloration and possibly even fluorescence of
>>> various coral colonies within a species, done in an attempt to attract
>>> the
>>> little fishes!?  Not only do the corals benefit from the presence of the
>>> fish, but the fish in turn require a clearly defined home site, hovering
>>> over the colonies as they feed on zooplankton, and having the absolute
>>> requirement to not stray far from their home colony.  A strong visual
>>> signal coming from the home colony would help them stay close to the
>>> safety
>>> of its branches.
>>>
>>> The sad thing is that sharing like this is not often done- everyone holds
>>> back on important findings and hypotheses that might help others and thus
>>> collectively help save coral reefs. What seems to be missing from science
>>> is an easy place to publish unverified speculations and observations like
>>> these, and without complications, so that the information can be accessed
>>> and used by researchers and graduate students who then go on to verify or
>>> disprove the ideas as they develop research topics of relevance to the
>>> present crisis.  Idea-people and those with years of field observations
>>> at
>>> the end of career would then have a greater impact.  These speculation or
>>> observations can then be referenced and the first to post them would get
>>> at
>>> least some of the credit!  This might be a way to encourage a vast and
>>> more
>>> open sharing of information? A rush to post new observations, ideas, and
>>> findings.
>>>
>>> In the present era, as the very survival of humanity is in question due
>>> to
>>> strains being made on the earth, just about every institution needs to be
>>> reinvented or transformed if we are going to avoid collapse of the
>>> planet,
>>> and academia is not exempt from this reinvention.
>>>
>>> Thanks and regards,
>>>
>>> Austin
>>>
>>> Austin Bowden-Kerby, PhD
>>> Corals for Conservation
>>> P.O. Box 4649 Samabula, Fiji Islands
>>> https://www.corals4conservation.org
>>>
>>> https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
>>> <
>>> https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
>>> >
>>>
>>>
>>> On Sun, May 29, 2022 at 11:22 AM Melbourne Briscoe <mel at briscoe.com>
>>> wrote:
>>>
>>> " The article, which proves bioturbulence for the first time is
>>> likely relevant to overfishing of the oceans in general."
>>> I don't understand how you conclude anything about overfishing from the
>>> article you link, which does not mention overfishing. Can you explain?
>>>
>>> I used to have an 1860's French textbook on "La Mer" that not only had
>>> drawings of the Kraken dragging down a schooner, but described the things
>>> that mixed the ocean, i.e. the sun, the moon, the rotation of the earth,
>>> and "the combined motion of all the little fish tails." Walter Munk's
>>> joking a century later was not a new idea.
>>>
>>> - Mel
>>>
>>> On Fri, May 27, 2022 at 5:06 PM Austin Bowden-Kerby via Coral-List <
>>> coral-list at coral.aoml.noaa.gov> wrote:
>>>
>>>
>>>
>>> https://eos.org/articles/tiny-creatures-may-play-a-difficult-to-detect-role-in-ocean-mixing?utm_source=EosBuzz&mkt_tok=OTg3LUlHVC01NzIAAAGEo_OQQIW0rqNZgyI-5z4UkTpsHp10Uek4dHjh4bgXqzxC0SqtKmfPEA6BYterhbNRI5v4ND60Wn_3l4twA-r0yDS-9ZstGMrMhYqIHcA
>>>
>>> The article, which proves bioturbulence for the first time is likely
>>> relevant to overfishing of the oceans in general.  Also I am wondering
>>> about corals and hiw highly branched species can get properly oxygenated
>>> and fed in calm waters, and as branching corals in general do poorly when
>>> fish numbers are too low.  I believe that the fish are the circulatory
>>> system of the corals, dissipating wastes and bringing in oxygenated
>>> waters
>>> to the corals at microscale, as well as "dusting off" settling silt and
>>> even sand from corals.  Has anyone studied the topic of bioturbulence in
>>> corals?
>>>
>>> Regards,
>>>
>>> Austin
>>>
>>>
>>> Austin Bowden-Kerby, PhD
>>> Corals for Conservation
>>> P.O. Box 4649 Samabula, Fiji Islands
>>>
>>>
>>> https://www.corals4conservation.org
>>>
>>>
>>> https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
>>> <
>>>
>>> https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
>>>
>>>
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