[Coral-List] FW: Does oil stick to coral mucus

Fri Aug 18 12:03:35 EDT 2006

To All:

In 1989 Gene wrote a great article for the magazine "Sea Frontiers"
entitled "What is really killing the corals?" (35:72-81) 

There are some great photos of the experiment he describes below. This
article is defintely a must read.

Cheers,

Bill

-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Gene Shinn
Sent: Friday, August 18, 2006 10:59 AM
To: "To:"@coral.aoml.noaa.gov
Subject: [Coral-List] Does oil stick to coral mucus

Chris Hind wrote: Does anyone happen to know how well exposed coral at
low tide can repel oil with its mucus? I will attempt an answer that may
be more than you wanted to know.
      First, I know you are aware that this is an emotion-loaded subject
conjuring up visions of oil coated seabirds and dead fish. 
Many will take issue with my response to this question but I think some
of this ancient history is in order. In the 1970s I wrote the section on
spills and corals reefs in the API oil spill handbook. It basically said
do not do anything. My chapter was based on some simple experiments and
observations conducted on the effects of crude oil in the summer of
1972. I did the experiment because I was being sent to Australia to be a
witness representing the industry at the Great Barrier Reef hearings
that took place in the wake of the crown of thorns episode. I felt a
little uneasy because no one knew what oil did to corals in those days.
The 2 year + series of hearings focused on the potential effects of oil
drilling on or near coral reefs. This two years before I left the
industry in 1974. to do coral reef geological research in Florida, and
elsewhere. I continue to monitor the literature on oil spills. To my
dismay little has been learned or attempted to be learned regarding the
effects of untreated crude oil on corals. There has been some research
on oil toxicity using the more toxic refined products, such as diesel
oil. The needed studies on toxicity of various crude oilsm however, has
to my knowledge never been conducted and I remain confident that no
government agency will ever fund the controlled experimental work that
is needed. Oil companies will not conduct the work because they pretty
much know the results already and also that their results would not have
credibility. In addition, young biologists will not become involved with
the subject due mainly to peer pressure and problems with tenure. It
would be a career-ending move for a young biologist. With all that said
here is some information that may provide some guidance. I can
confidently state that crude oil does not stick to coral mucus even if
you can get the floating oil on the coral in the first place.
      Before going to Australia to present my previously published data
on Acropora growth rates I obtained 5-gallons of Louisiana crude and
headed for the Florida Keys on holiday. I already knew that the Great
barrier reef corals are exposed to the air at low tide for up to 1.5
hours. That is when corals can come in direct contact with floating oil.
In my simple experiments Acropora cervicornis was attached to rods
driven into the bottom off Key Largo. Clear 5-gallon-sized plastic bags
were placed over the corals and tied to the rod below the coral
colonies. One bag contained about one gallon of crude oil and half of
the coral colony protruded into the oil that floated at the top of the
bag. In another bag the coral was only in contact with the water below
the oil that floated at the top of the attached bag. Another was a
control with no oil. Yet another experiment involved small Montastrea sp
heads placed under 2 Lucite plastic domes. One was in direct contact
with the oil under the dome and another was a control. Both experiments
lasted 1.5 hrs to simulate the exposure time on the Australian barrier
reef. A. 
cervicornis immediately retracted its polyps in the bags containing
crude. When I removed the bags it was obvious that the oil would not
adhere to the coral. That was the first surprise. The second was that,
14 days later I returned to the site and found the corals alive. They
appeared healthy, the polyps were extended but I had no way of knowing
their true condition. Montastrea also did not appear to be harmed.
Photos of the experiment were published in a Sea Frontiers article in
1989. With this information in hand I went to the Barrier Reef Hearings
feeling a little more relieved and confident. At the hearing I read
testimony about an Australian who had had done a related experiment.
Using a back-pack sprayer this person had repeatedly sprayed a 10 by 10
m area of the reef at low tide. His results were similar to mine. I
believe these simple, mainly anecdotal, experiments answer the basic
question of whether or not oil sticks to coral mucus.
     Later after leaving the industry I did a similar experiment with a
student off Miami. We totally immersed A. cervicornis in crude for an
hour in the laboratory and then transplanted the colonies out to the
reef. They remained alive for several weeks until the student decided
this was not the result she was seeking.
     Over the years it has been interesting to note that when there is a
crude oil spill on or near a coral reef the media predicts disaster yet
none have reported death of corals or reef fish. I think because the
media never presents the facts the public, including many coral reef
researchers, have become very polarized. What we do know for sure is
that the damaging effects occur when the oil reaches shore, often due
mainly to the clean-up methods.
     The most devastating spill, (reported in Science) was the one near
Goleta Point in Panama in the early 1980s mentioned by John Cubit. This
was a case of onshore tanks spilling into the ocean and passing over the
Goleta Point coral reef adjacent to the Smithsonian Institution field
station. That oil was treated with dispersants, according to my
information, and yes, corals began to die on the adjacent reef, (I don't
recall that  there were intertidal corals on this reef when I visited
the reef in 1974). Many respected scientists were witness to this event
and Minerals Management Service funded the subsequent study published in
Science. In retrospect what we know now, but did not know then, was that
this was also the beginning of the Caribbean-wide coral demise that
continues today. The years
1983-1984 (also el Nino years) were the most devastating for Acropora
corals throughout the Caribbean including those on reefs around sparsely
populated islands.
     If one conducted the same simple exposure experiments I did in
1972 under todays conditions it is very likely the even the controls
would die. Something changed radically beginning in the late 1970s and
began peaking in the early 1980s. Bleaching appeared in the late 1980s.
Ongoing coral diseases whose source has not been scientifically
determine has been well documented and continues even around Caribbean
islands isolated from the usual pollutants. Corals, even in isolated
places like Dry Tortugas have declined and lack their former resilience.
E. A. Shinn

-- 

No Rocks, No Water, No Ecosystem (EAS)
------------------------------------ -----------------------------------
E. A. Shinn, Courtesy Professor
University of South Florida
Marine Science Center (room 204)
140 Seventh Avenue South
St. Petersburg, FL 33701
<eshinn at marine.usf.edu>
Tel 727 553-1158----------------------------------
-----------------------------------
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