[Coral-List] Reply to Charles Birkeland

Gene Shinn eshinn at marine.usf.edu
Mon Aug 21 14:44:32 EDT 2006

Dear Chuck, Thanks for responding to my observations about "crude" 
oil and corals. I recall from my 1974 visit to Goleta Point where you 
had conducted the study that there were also test panels coated with 
various refined oils. Were they were part of the study you were 
conducting? The treated panels were placed on the reef just off the 
laboratory and they had a Braille-like system on them to allow 
recognition because during the monsoon season the water on that reef 
looks like coffee with cream. Fortunately, I visited during the dry 
season but was still amazed that corals, especially Acropora could 
survive there. As I remember, visibility during the dry season (when 
we were there) was no more than 30 ft yet the full complement of 
Atlantic corals was present. Ian MacIntyre and Peter Glynn were just 
finishing up the core drilling that demonstrated how the reef, and 
reef flat, had been constructed by A. palmata over the past few 
thousand years.
      I have always been impressed with the knowledge that this 
classic study demonstrated that A. palmata had grown to the surface 
and had accreted seaward and produced a broad reef several meters 
thick in spite of such poor water quality. Yes, Acropora was much 
more hardy before the 1980s.
      As I pointed out in my note to the coral list, crude oil is less 
toxic than refined oils such as bunker C (which will sink) and diesel 
oil that floats and is more water-soluble is even more toxic. 
Considering water conditions at Goleta Point and the greater toxicity 
of the oils tested, it is amazing that that your corals survived even 
though their growth rate was reduced. (They were still living after 
61 days! How long did they live?)
      Also, as I stated, I do not know the ultimate fate of the coral 
I treated and would not be surprised if their growth rate had been 
reduced. I emphasize again that crude oil, the kind most often 
spilled during transoceanic shipment, (or from an offshore blowout) 
floats and is less toxic than refined products, such as the 6 billion 
gallons transported by ships into Tampa Bay each year. To my 
knowledge coral bioassays have yet to be conducted using crude oil 
and I wager that such studies will not be attempted. Gene

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