[Coral-List] Rebar, & algae & paint; compiled responses

Michele & Karl michka at fellenius.net
Tue Dec 6 01:45:39 EST 2005

Coral Listers,

I read your responses with interest. I am not surprised by your anti-fouling
responses and I am somewhat relieved. I was looking for valid reasons not to
use this stuff. I can only strongly recommend for or against its use and I
wanted to compile your points of view. Be assured that its use will remain
on the experimental level.

The argument here is that toxics would not kill or inhibit coral growth
because the corals are on pieces of rock that are in turn attached to the
mesh. I am of the opinion that proximity, and not just contact, kills. So
would it be correct to say that copper sulphate anti-fouling paint used
either on both the mesh and the rebar, or even just the rebar, would likely
have a toxic or at least an inhibiting effect on the growth of coral?

Again, thanks for any responses.

Karl Fellenius
Reef Solutions Vanuatu

> Your message was forwarded to me.  Dissolved iron serves as a limiting
> nutrient in many tropical marine areas and tends to fuel cyanobacteria
> (blue-green algae) growth when the iron begins to dissolve (corrode). This
> is especially a problem on atolls and low coral islands where
> basalt/volcanic rock is absent in the photo zone and natural dissolved
> sources of iron in seawater are even lower.
> In fact if you have iron shipwrecks in your area, you will probably see
> many of the same types of cyanobacteria proliferating.
> The solution to your problem is simple, use high grade stainless steel
> designed for use in wet marine environments and don't use rebar!   I
> noticed in Okinawa Japan that some firms growing corals use brass pins to
> attach corals. Brass apparently doesn't corrode much either. A third
> alternative is to use plastic pins or stakes such as those used to tie down
> camping tents.
> I hope these comments are useful and understood.  If not get back to me for
> more clarification.
> Good luck!  Jim
> ********************************************************************
> Jim Maragos, Ph.D. Coral Reef Biologist & Field Dive Officer
> Pacific/Remote Islands National Wildlife Refuge Complex
> U.S. Fish and Wildlife Service
> 300 Ala Moana Blvd., Rm 5-231, Box 50167
> Honolulu, HI 96850 USA
>   Another thing maybe to try when cruising the local (and likely limited)
> hardware store could be a heavy-duty/hard-waring oil or boat fiberglass paint,
> or even fiberglass clear-coat. There are two-part epoxy paints as well. Very
> tough and cheaper/easier to get for you.
>   Best and easiest bet: Check the local car-painting/panel-beater operation.
> They'll even do your painting for you on any shape you produce, and likely
> cheaper and easier. Painting mesh is no fun with a brush.
>   I'd strongly suggest you stay away from copper based anti-foulant. Copper is
> BAD. I've made that mistake.... Antifoulants work as they are poisonous.
>   You've certainly stirred up lots of interest. Good luck, have fun and keep
> us posted.
>   Andrew
> There is a paper in the latest online Marine Biology where they looked at
> the toxicity of various heavy metals on coral larvae ... copper was number
> one, zinc much lower.
> As to the iron feeding the growth, I am not convinced of this unless the
> cyanobacteria are releasing free iron by enzymatic actions. I have seen
> rebar and mesh structures used in the Solomon Islands with no cyanobacteria
> evident on them ... so why they be the cause in your area? The problem may
> be a lack of herbivores??
> Aloha!
> J. Charles Delbeek M.Sc.
> Aquarium Biologist III
> Waikiki Aquarium
> 2777 Kalakaua Ave.
> Honolulu, HI, USA 96815
> www.waquarium.org
> First of all, painting antifouling paint on your bars will replace a
> minor problem with a major one. These paints are bad news, toxic to
> humans, and VERY toxic to ALL marine life. This will kill the corals
> you are trying to raise.
> Secondly, Fe has never been shown to be limiting in shallow tropical
> environments. Only tiny amounts are needed, because it is so quickly
> recycled. Those huge open-ocean Fe-experiments were basically
> fauilures. The Fe was taken up quickly by the algae, which then all
> died and sank down 4km. Fe all gone.
> In short, i doubt very much the rebar is the source of the problem.
> Mike Risk
> I would be very careful about using antifouling paints!  there are
> designed to inhibit photosynthesis (of plantonic algae) and therefore
> limit fouling on boats.  they have the same inhibitory effect on
> photosynthesis of the coral's zooxanthellae (algae cells).  So you might
> actually end up damaging the coral.
> I certainly know this to be true of the TBT, and pesiticide based
> antifouling paints (such as Irgarol), although I haven't researched
> copper specifically.
> I have had a look at your website.  It looks like you have a great
> project going over there.  I might be swinging through the Pacific next
> year, if so, I would be keen to meet up.
> All the best with your work,
> Lucy
> Aquatic Photosynthesis Group, University of Technology, Sydney.
>   Followed the below with interest. I have several suggestions. Antifouling
> paint also comes in the form of silicon-based compounds - a lot less harmful
> than tin/copper associated paints.
>   I think you need to look at why you use rebars. Is there a material you can
> use to do the same job?
>   Can you use PVC/porcelain instead? By porcelain i mean use sometinhg like
> the eco-reef module. This would be far more environmentally benign/sustainable
> than the rebar method and look a lot prettier thus attracting eco-tourists to
> your "farms".
>   Just me thoughts
>   Iain Macd

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