[Coral-List] Artificial reef - cement or metallic /w electrical stimulation?

[McManus, John W]

There is a literature on the subject of using electrical current to enhance coral growth and survival. One such paper, which cites several previous ones,  is:

Sabater and Yap 2004 Long-term effects of induced mineral accretion on growth, survival and corallite properties of Porites cylindrica Dana. Journal of Experimental Marine Biology and Ecology 272:131– 146


Here are some quotes which highlight some key results:


"P. cylindrica transplants had a survival rate of 86% after 6 months of exposure to mineral accretion, which was higher than that of the untreated corals (70%)."

"Through time, the cathode becomes saturated by the accreted minerals resulting in a decreasing interaction between the two electrodes until the accretion stops. Thus, the effect of mineral accretion on growth dissipates through time. This explains why significant increases in longitudinal growth were found only for the first two bi-monthly intervals during the mineral accretion phase after which growth rates were no longer significantly
different over time. The mineral accretion treatment did not have a significant effect on growth at the end of the 12-month experiment. Growth enhancement, therefore, occurred only when the electric field was present which caused an increase in the dissolved mineral ions around the coral transplants utilized for skeleton formation and mineral accretion for
substrate formation."

Note that these were not exactly the same structures used by Goreau.


Cheers!


John



________________________________
From: coral-list-bounces at coral.aoml.noaa.gov <coral-list-bounces at coral.aoml..noaa.gov> on behalf of Bill Allison <allison.billiam at gmail.com>
Sent: Monday, July 10, 2017 5:51:17 AM
To: Philippe Sanchez; coral-list coral-list
Subject: Re: [Coral-List] Artificial reef - cement or metallic /w electrical stimulation?

Hi Philippe,
Thanks for the response.
I have heard it asserted that aragonite can be formed by fine-tuning the
current. I'm very interested in reading the research paper demonstrating
this and how it can be effected in real life. Please provide a citation.
Thanks



On Mon, Jul 10, 2017 at 1:54 AM, Philippe Sanchez <pipobs at gmail.com> wrote:

> Hi Bill,
>
> More and more I think reef balls wouldn't be the best approach. I have
> read that the reefs can be powered by using renewable energy (tide action,
> wind or solar). Since there is plenty of sun, maybe solar panels would be a
> good idea.
>
> Others have told me that the cations/anions formed can be controlled
> depending on the positioning of the cathode.
>
> "Incidentally, whether you get brucite or aragonite depends on the
> specifics of the current supplied"
>
> Thanks for you input!
>
> Philippe
>
>
> On 9 July 2017 at 15:20, Bill Allison <allison.billiam at gmail.com> wrote:
>
>> Hi Philippe,
>> You might want to consider:
>>
>> 1. Production of both concrete (reef balls) and steel (electro reef) have
>> large carbon footprints.
>>
>> Transport of materials and transport and emplacement of the structures
>> also produce carbon dioxide and heat.
>>
>> I have not seen a cost-benefit incorporating these considerations.
>>
>>
>>
>> 2. Re. electric current approach.
>>
>> A negative current will draw cations and a positive current will draw
>> anions.
>>
>> Presumably the Ca2+ and Mg2+ are of interest but there are other cations
>> out there.
>> The area becomes supersaturated with cations and whatever is in the
>> vicinity will be precipitated.
>> The amorphous mass formed is mostly brucite and unlikely to crystalize.
>>
>> Good luck,
>> Bill
>>
>>
>> On Thu, Jul 6, 2017 at 7:24 AM, Philippe Sanchez <pipobs at gmail.com>
>> wrote:
>>
>>> Hi all,
>>>
>>> I've been looking at some artificial reef projects, specifically in the
>>> UAE. Reef balls seem to be quite popular. A friend recently told me about
>>> increasing growth and survival rate by applying a small electrical
>>> current
>>> (I'd never heard of this before). I read the paper (Goreau, T.J. 2014)
>>> and
>>> it seems very promising. I wondered why this wasn't more well known??
>>> Perhaps it's too expensive for people to set up?
>>>
>>> Does anyone here have any experience working with such a project or can
>>> give some insight on the pros and cons of this innovative method?
>>>
>>> Thanks!
>>> _______________________________________________
>>> Coral-List mailing list
>>> Coral-List at coral.aoml.noaa.gov
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>>>
>>
>>
>>
>> --
>> "... the earth is, always has been, and always will be more beautiful
>> than it is useful."
>> - Ophuls, 1977
>> "My name is Ozymandias, King of Kings;
>> Look on my Works, ye Mighty, and despair!"
>> - Shelly
>>
>
>


--
"... the earth is, always has been, and always will be more beautiful than
it is useful."
- Ophuls, 1977
"My name is Ozymandias, King of Kings;
Look on my Works, ye Mighty, and despair!"
- Shelly
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