[Coral-List] Mixed Messages; Barbados vs. Cuba's Garden: it's nutrients, but not sewage.
Risk, Michael
riskmj at mcmaster.ca
Mon Aug 12 17:58:56 UTC 2019
Hi Joe.
Huh, coulda sworn you were trying to prove something...people quoting
Yogi Berra generally are. Nonetheless, I am prepared to accept this
thread is thoroughly thrashed.
I am intrigued by the concept that old science may not be good science
(does Darwin know this?). Tom Tomascik's work on Barbados reefs is of
course classic, and anyone working on reefs anywhere (and Barbados
especially) should read it. I am informed (as of yesterday) by people
working in Barbados that the picture is worse than I implied, with
widespread coral damage correlating with nutrient increases. Papers are
in prep-but really, by now we should all know this.
On this theme, I recommend to the -list a recent paper by Liam Lachs et
al, on sewage on coral reefs: Mar Poll Bull 148: 85-96 (no, I didn't
write it: self-promotion's not my thing) in which may be found
"Potential damaging effects of sewage discharge on the coral reef
communities at both islands are highlighted by strong correlations
between Acropora d15N and regional variation in coral reef community
structure, and exclusive occurrence of degraded reefs at regions of
high sewage influence."
Au revoir-Mike
On Aug 10, 2019, at 11:37 AM, Pawlik, Joseph via Coral-List
<[1]coral-list at coral.aoml.noaa.gov> wrote:
Hi Mike,
I would never try to "prove" anything, and would hope that the latest
group of reef scientists would also be reasonably skeptical of any
explanation of ecosystem-level functioning, particularly based on
decades-old data.
Instead, I would ask them to get out there and study the reefs right
now and see how past hypotheses hold up. They should be equally
skeptical of recent hypotheses, my own included.
With that, I am signing-off on this thread.
Joe
**************************************************************
________________________________
From: Risk, Michael <[2]riskmj at mcmaster.ca>
Sent: Saturday, August 10, 2019 7:38 AM
To: Pawlik, Joseph
<[3]pawlikj at uncw.edu>; [4]coral-list at coral.aoml.noaa.gov <[5]coral-list
@coral.aoml.noaa.gov>
Subject: RE: [Coral-List] Mixed Messages; Barbados vs. Cuba's Garden:
it's nutrients, but not sewage.
Joe:
The last time somebody asked me to watch a YouTube video that "proved"
something, it was some guy at Heartland Institute who claimed to
disprove global warming.
This thread began when I characterized Barbados as an "outhouse on a
karst outcrop." Angie Brathwaite took offense, and it's hard to blame
her-those were tough words. Angie's a friend, and a good person. I was
sorry I had offended her, so I apologized. But there was more than a
grain of truth in my comment.
We don't have to depend on tourists' YouTube videos here: science does
not advance via social-media postings. VIMS has carefully tabulated the
available evidence on marine habitats, identified marine "dead zones"
(areas of oxygen depletion due to organic loading), and posted the
results on Google Earth with a scary fish-skeleton icon. Barbados has
the only dead zone from the coast of Venezuela north to the latitude of
Puerto Rico. The accompanying text says "Its waters suffer from
eutrophication due to fecal matter in the water."
Joe, it is good that Tom has set you straight on Barbados-you might
have contacted him before going down, because he really knows those
reefs. The rest of your post seems to be an extended infomercial for
your latest research.
I am interested in your comment that "it's nutrients but not
sewage"-because this seems to fit the all-too-common pattern of reef
biologists being chemically naive. Sewage IS nutrients-plus everything
else we put down the toilet. Once those phosphates and nitrates are
released into the water column, it can be very hard to trace their
source. But we do have tools, and I would be glad to help you out here.
One of the handiest tools is stable isotopes of nitrogen, delta 15-N.
This is a trophic indicator, increasing with each step in the food
chain. It works so well because humans are the main top carnivore
pooping in the ocean. Similarly, coprostanol is a fecal steroid, often
used as a sewage tracer. Analyses for coprostanol are difficult and
expensive, 15-N are easy and cheap, and work at least as well as
tracers of sewage (Bachtiar et al, 1996: Sci Total Env 179: 3-16).
A host of other tracers have been used, such as caffeine, residues of
birth-control pills, etc. There are many tools available that will
allow us to tell sewage nutrients from other sources-for example,
nitrogenous fertilizers are synthesized from atmospheric N, hence their
15N signal is zero-sewage N will be higher. To add to this bag of
tricks, Environment Canada is doing some very cool work using P
isotopes to tease out sources of nutrients in agriculture.
In short, your assertion that the nutrients were not sewage does not
seem supported by adequate data. Like many reef biologists, you invoke
the Diadema dieoff...yet this just-so story is not adequately supported
by the data. When I look at Gardner's figure, I see the decline in
Caribbean reefs decreasing monotonically with no vestige of a Diadema
Dimple. Some data might help, as well as looking at some of the
published descriptions of stress on Cuban reefs (e.g. Risk et al.,
2014, Mar Poll Bull 83: 282-89).
If you, or anyone else reading this, would like help navigating this
array of indicators, just contact me off-list. I am not sanguine,
however: the 15-N technique, for example, was first applied to reefs
almost 30 years ago, and in 1992 (Reef Encounter) I suggested it be a
routine part of any reef monitoring program. Reef biologists still
spend millions of dollars counting critters, when a few tens would go a
long way to providing answers.
Mike
________________________________________
From: Coral-List [[6]coral-list-bounces at coral.aoml.noaa.gov] on behalf
of Pawlik, Joseph via Coral-List [[7]coral-list at coral.aoml.noaa.gov]
Sent: August 8, 2019 7:54 AM
To: [8]coral-list at coral.aoml.noaa.gov
Subject: Re: [Coral-List] Mixed Messages; Barbados vs. Cuba's Garden:
it's nutrients, but not sewage.
Mike,
As a reminder of the "purpose of this post", you referenced SW Barbados
as "..an outhouse built on a karst outcrop" to make a point about
sewage destroying coral reefs.
I provided recent video from the same location you referenced to
indicate that those reefs look pretty good.
As Yogi Berra may have said "You can see a lot by looking!"
With that in mind, I ask coral-listers to compare two videos of reefs,
taken less than a year apart (March 2018, Jan 2019):
Cuba's Garden of the Queen, considered by many as "pristine" as a coral
reef can be in the Caribbean:
[9]https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fyo
utu.be%2FKZWeYIeHTyk&data=01%7C01%7Cpawlikj%40uncw.edu%7C123c3116c7
7b4aa339da08d71d8749d3%7C2213678197534c75af2868a078871ebf%7C1&sdata
=YjSFJ9Skj55ubzrVFANnNWdR3dk%2FmOSskYQjej%2Fg2PY%3D&reserved=0
And the reefs of SW Barbados, directly offshore from an island heavily
populated for hundreds of years and very close to Bridgetown (see Mike
Risk's summary at the bottom of this email):
[10]https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fy
outu.be%2FpFA5pw5FMVE&data=01%7C01%7Cpawlikj%40uncw.edu%7C123c3116c
77b4aa339da08d71d8749d3%7C2213678197534c75af2868a078871ebf%7C1&sdat
a=3XQ7w37H4mRAccMbxAkNu1MsdMpooZGmWA2nDJMGMcU%3D&reserved=0
Which reefs looks "better" to you??
To my eye, coral cover is similar, but there's a lot more seaweed on
Cuba's reefs.
And, Mike, Cliona delitrix has higher cover in Cuba - see large patches
at time points 5:31 and 6:56.
Why the difference in seaweed cover? Because Diadema populations are
higher on reefs off SW Barbados, unlike Cuba (even though Cuba has lots
of big fishes, including large parrots, while Barbados is heavily
overfished). Notice the pink coralline crusts in the Barbados video
that you don't see in the Cuba video - too much seaweed there.
Again, please notice the high biomass of barrel sponges in both
locations, and lots of sponges in general.
While in Barbados, I met a local who started diving there in the 1960s,
and I asked him what the biggest changes he'd seen to the reef - he
said the two most obvious things were the loss of Acropora corals and
the increase in giant barrel sponges.
This is about nutrients, but not about sewage (at least not at broad
geographic scales) -- the nutrients (and DOC) are tightly cycled in the
ecosystem.
In Cuba, all those sponges are making nutrients (from eating algal DOC
and phytoplankton) as they disrupt the boundary layer and churn the
water column, which fertilizes the seaweeds. All those fishes also make
nutrients, and fish herbivory can't keep up with seaweed growth. The
ecosystem was altered when coral and urchin diseases went through in
the 1970s and 1980s, freeing real estate, removing a critical herbivore
(urchins), and allowing seaweeds to take-over quickly, followed by
sponges. This is the vicious circle (see ref below).
In Barbados, the returning urchin populations seem to be controlling
the seaweed, despite sponges already having taken significant real
estate. Interestingly, this is in the absence of strong fish herbivory.
And correlations of boring sponge abundance (cover) with "pollution"
are confounded by coral loss and increases in boring sponge habitat.
The vicious circle and the relationship between sponge cover and
"pollution" are topics covered here:
Pawlik, J.R., McMurray, S.E. 2020. The emerging ecological and
biogeochemical importance of sponges on coral reefs. Annual Review of
Marine Science, 12: 3.1-3.23
You can find a copy at the PDF site below.
Regards,
Joe
**************************************************************
Joseph R. Pawlik
UNCW Center for Marine Science
PDFs: [11]https://nam05.safelinks.protection.outlook.com/?url=http%3A%2
F%2Fpeople.uncw.edu%2Fpawlikj%2Fpubs2.html&data=01%7C01%7Cpawlikj%4
0uncw.edu%7C123c3116c77b4aa339da08d71d8749d3%7C2213678197534c75af2868a0
78871ebf%7C1&sdata=HEZCaQ0q1pnV7TmozPPlws7VJvkPcLqYfvS0Ukg7IHA%3D&a
mp;reserved=0
Video
Channel: [12]https://nam05.safelinks.protection.outlook.com/?url=https%
3A%2F%2Fwww.youtube.com%2Fuser%2Fskndiver011&data=01%7C01%7Cpawlikj
%40uncw.edu%7C123c3116c77b4aa339da08d71d8749d3%7C2213678197534c75af2868
a078871ebf%7C1&sdata=nGmOVHFFXvnbCgJ2DR8si664DruCY3FoODQq9TMHysA%3D
&reserved=0
**************************************************************
-----Original Message-----
From: Risk, Michael <[13]riskmj at mcmaster.ca>
Sent: Wednesday, August 7, 2019 3:16 PM
To: Pawlik, Joseph
<[14]pawlikj at uncw.edu>; [15]coral-list at coral.aoml.noaa.gov
Subject: RE: [Coral-List] Worthing, Barbados
I'm not sure of the purpose of this post-but then, I wasn't sure of the
purpose of the original one.
Boring sponges are a lot harder to locate and identify. It takes time
to get your eye in-I would be glad to give you some pointers off-list,
if you like. You seem to be aware of the importance of C delitrix, so I
assume counts of its abundance are in your census papers.
I wanted to take the opportunity to inform -listers of the amount of
good work that came out of the Bellairs Lab before the McGill Admin
chased a different shiny object. There is a ton of grey literature
stuff (search for Bellairs Lab Publications)-it's all pretty old, but
data never die.
________________________________________
From: Pawlik, Joseph [[16]pawlikj at uncw.edu]
Sent: August 7, 2019 1:12 PM
To: Risk, Michael; [17]coral-list at coral.aoml.noaa.gov
Subject: RE: [Coral-List] Worthing, Barbados
Not sure we're watching the same video, Mike,
I count less than 25 small patches of C. delitrix in the whole video,
with several of those clumped on the same rock.
Again, much lower abundance, in my experience, than many Caribbean
reefs.
**************************************************************
-----Original Message-----
From: Risk, Michael <[18]riskmj at mcmaster.ca>
Sent: Wednesday, August 7, 2019 12:18 PM
To: Pawlik, Joseph
<[19]pawlikj at uncw.edu>; [20]coral-list at coral.aoml.noaa.gov
Subject: RE: [Coral-List] Worthing, Barbados
Yes, thanks for that.
I note your video contains almost as many colonies of the fecal
bioindicator Cliona delitrix, a boring sponge, as of giant barrel
sponges.
Those interested in what science has to say about those reefs are
encouraged to read the seminal work out of McGill, especially Tom
Tomascik's stuff, and the 2002 paper by John Lewis that documents coral
loss.
Coastal Zone also runs regular monitoring.
________________________________________
From: Coral-List [[21]coral-list-bounces at coral.aoml.noaa.gov] on behalf
of Pawlik, Joseph via Coral-List [[22]coral-list at coral.aoml.noaa.gov]
Sent: August 6, 2019 3:54 PM
To: [23]coral-list at coral.aoml.noaa.gov
Subject: Re: [Coral-List] Worthing, Barbados
The SW coast of Barbados has better coral cover and lower seaweed cover
than many reefs elsewhere in the Caribbean. Here's a video tour from
January 2019:
[24]https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fy
outu.be%2FpFA5pw5FMVE&data=01%7C01%7Cpawlikj%40uncw.edu%7C123c3116c
77b4aa339da08d71d8749d3%7C2213678197534c75af2868a078871ebf%7C1&sdat
a=3XQ7w37H4mRAccMbxAkNu1MsdMpooZGmWA2nDJMGMcU%3D&reserved=0
Notice the huge biomass of giant barrel sponges!!!!
**************************************************************
Joseph R. Pawlik
**************************************************************
From: Coral-List <[25]coral-list-bounces at coral.aoml.noaa.gov> on behalf
of Angie via Coral-List <[26]coral-list at coral.aoml.noaa.gov>
Sent: Monday, August 5, 2019 11:27 AM
To: Coral List <[27]coral-list at coral.aoml.noaa.gov>
Subject: Re: [Coral-List] Worthing, Barbados
According to Dr. Risk.Barbados is "...an island which could be
characterized as an outhouse built on a karst outcrop". That's pretty
uncharitable. I'm trying as a Barbadian not to be offended and as a
scientist to stick to facts so I have to add that we have two sewage
treatment plants, one primary servicing the south and slated to be
upgraded to tertiary and the other secondary, servicing the Capital. An
increasing number of householders are choosing septic tanks over the
traditional suck wells and our nearshore water quality (which is
monitored twice monthly) is not the sewer one would expect given that
analogy.
Angelique Brathwaite
_______________________________________________
Coral-List mailing list
-----Original Message-----
From: Coral-List <[28]coral-list-bounces at coral.aoml.noaa.gov> On Behalf
Of Risk, Michael via Coral-List
Sent: Saturday, August 3, 2019 4:05 PM
To: Amelia Wenger <[29]amelia.wenger at gmail.com>; Coral List
<[30]coral-list at coral.aoml.noaa.gov>
Subject: [Coral-List] Worthing, Barbados
Amelia asked me for some information on Worthing, and I realized that
although I have mentioned this several times, there is not a lot
available that can be easily accessed. Because it seems to represent
significant findings for the Caribbean, allow me to present an
outline
here.
15-odd years ago, I begin working on a variety of Barbados projects
with Baird Engineering, a Canadian firm of coastal engineers. My
interaction with them produced what I think are some good pieces of
science (Risk et al. 2009, Tracking the record of sewage off Jeddah,
Saudi Arabia: MEPS 397: 219-226; Risk et al. 2010, Trace elements in
bivalve shells: Aq. Biol. 10: 85-97).
Some time in 2004, I ran some surveys on the south coast of
Barbados.
At Worthing (between Oistins in the east and Bridgetown to the west)
there is a large, dynamic beach called, in an excess of originality,
Sandy Beach. There are large offshore bars at the site, covered with
dead Acropora palmata debris.
Late in the previous century and early in this one, the beach on the
west accreted seaward until it met the offshore bar, cutting off the
channel that had separated the beach from the bar and creating a
small
lagoon with restricted circulation. My surveys in that lagoon in
early
2004 showed evidence of recent environmental deterioration:
recently-dead coral colonies, Diadema so freshly dead that the spines
were still attached, etc. Surveys indicated that the water quality
had
decreased recently, due to lack of flushing.
Hurricane Ivan hit in Sep 2004, and blew the west end of the lagoon
open. The benthic habitat there was newly-exposed to relatively fresh
seawater. I say "relatively", because that water would have travelled
at least 5km along the south coast of Barbados, an island which could
be characterized as an outhouse built on a karst outcrop.
Nonetheless,
an improvement on the previous situation. This seemed an opportunity
to
study the response of the biota to an improvement in WQ.
We installed racks of settling plates in the lagoon, and commenced
benthic surveys: this work was mostly done by personnel of the
Coastal
Zone Management Unit and UWI. Gorgonians from the offshore bar
recorded
a drop in delta-15N from 6.5 per mille to below 4, coinciding with
the
increased flushing following Ivan. Surveys on a small rubble reef in
the middle of the lagoon between Mar 2005 and Sept 2005 showed a
5-fold
increase in numbers of Diadema (and an increase in urchins in
general),
a modest increase in fish species and an explosion of coral recruits.
Coral-associated molluscs such as Tritons and juvenile Strombus began
to appear. Coral spat were found on our settling plates, mostly
sediment-resistant species such as Siderastrea. Spat were identified
by
Judith Mendes and Paul Sammarco.
We viewed this as a convincing demonstration of the value of improving
water quality. I published an Abstract (in 30th Congress of the
International Association of Theoretical and Applied Limnology.
Montreal, Canada, 2007) so that there would be something citable while
I worked up the paper.
Senior management at Baird changed, and I resigned from the Barbados
project.
(Those wishing details may contact me personally.) It is doubtful I
will ever have the opportunity to write this up for a full journal
paper. We have to dance with who brung us here.
The Worthing example is encouraging, but limited in scope. There will
never be a flourishing reef at Worthing, because of the high
sedimentation loading.
As well...the beach is starting to accrete again, there is discharge
from the Graeme Hall Swamp...this little experiment may already have
ended. The conclusions remain.
Mike
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