[Coral-List] Mixed Messages; Barbados vs. Cuba's Garden: it's nutrients, but not sewage.

Thu Aug 8 11:54:00 UTC 2019

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:
https://youtu.be/KZWeYIeHTyk
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):
https://youtu.be/pFA5pw5FMVE

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: http://people.uncw.edu/pawlikj/pubs2.html
Video Channel: https://www.youtube.com/user/skndiver011
**************************************************************

-----Original Message-----
From: Risk, Michael <riskmj at mcmaster.ca> 
Sent: Wednesday, August 7, 2019 3:16 PM
To: Pawlik, Joseph <pawlikj at uncw.edu>; 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 [pawlikj at uncw.edu]
Sent: August 7, 2019 1:12 PM
To: Risk, Michael; 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 <riskmj at mcmaster.ca>
Sent: Wednesday, August 7, 2019 12:18 PM
To: Pawlik, Joseph <pawlikj at uncw.edu>; 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 [coral-list-bounces at coral.aoml.noaa.gov] on behalf of Pawlik, Joseph via Coral-List [coral-list at coral.aoml.noaa.gov]
Sent: August 6, 2019 3:54 PM
To: 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:

https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fyoutu.be%2FpFA5pw5FMVE&data=01%7C01%7Cpawlikj%40uncw.edu%7Cf5da1101d96b48579d5908d71b6bb32c%7C2213678197534c75af2868a078871ebf%7C1&sdata=oGCJ8SRevp74wdFxQT4vCV0fVmgVtc%2Flx8JBTLR1mWY%3D&reserved=0

Notice the huge biomass of giant barrel sponges!!!!

**************************************************************

Joseph R. Pawlik

**************************************************************

From: Coral-List <coral-list-bounces at coral.aoml.noaa.gov> on behalf of Angie via Coral-List <coral-list at coral.aoml.noaa.gov>
Sent: Monday, August 5, 2019 11:27 AM
To: Coral List <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

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-----Original Message-----
From: Coral-List <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 <amelia.wenger at gmail.com>; Coral List <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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