Four Reefs after Hurricane Georges

[J. Charles Delbeek]

This brings up an interesting possibility. It is generally accepted that
the Caribbean and FL areas have been in a lull when it comes to hurricanes
over the last 20-30 years. According to hurricane forecasters, we are now
entering a cycle of renewed hurricane activity in the region for the next
twenty years or so. 

Could it be that the increased presence of macroalgae in reef areas in the
region could be the by-product of reduced "cleansing"  of reef tracts by
hurricanes?

In closed aquarium systems it is not uncommon to experience increased
algal growth in areas where sediments/detritus accumulates. Aquarists
often mimic "mini-hurricanes" by agitating the water either by hand or via
powerheads set on timers, to dislodge this accumulated sediment and remove
it from the system via mechanical filters. 

Food for thought ...

J. Charles Delbeek M.Sc.
Waikiki Aquarium
University of Hawaii

"The fact that my physiology differs from yours pleases me to no end." 
Mr. Spock


On Wed, 7 Oct 1998, George S. Garrett wrote:

> Coral-list folks:
> 
> Hurricane Georges passed through the Florida Keys in the early afternoon and evening of Friday 25 September.  Damage to the human environment of Keys was significant, but it could have been much worse.  Damage to the natural environment of the Keys seems to be much less significant.  Concern was immediately raised as to the potential impacts of Georges on the Florida reef tract.
> 
> Local photographer Larry Benvenuti (see some of his photos on the AOML Web site) and I briefly surveyed four reef areas in the Middle Keys area near Marathon on 2 October 1998; Coffins Patch (FKNMS SPA), Coffins Patch Light, Sombrero Deep Reef, and Sombrero Reef (FKNMS SPA).  Without going into detail our conclusion is resoundingly that the hurricane did a lot to clean up these reef areas.  We saw little evidence at any of these sites that there had been significant damage to hard and soft corals or other sessile invertebrates.  We saw little evidence of either overturned coral heads or of broken coral branches.  On the other hand, much of the macro-algal overgrowth, silt, and detritus that has been in evidence over the past Summer and in past years seems to have been scoured away.  As the substrate for our reef is in fact an ancient reef, those "rock" surfaces are in many cases bare.  This was particularly true at Coffins Patch Light and at Sombrero Deep Reef.  Coffins Patch and Sombrero Reef show considerable coral bleaching, particularly to brain corals, fire corals, some shallow encrusting corals, and lesser to Star corals unrelated to the hurricane, but all except the brain corals seem to be recovering at these locations.  Brain corals remain essentially completely bleached, particularly at Sombrero Reef.  Time will only tell there.
> 
> Evidence of extreme wave conditions resulting from the storm exist at Coffins Patch Light.  The light there, consisting of several approximately 16-18" steel I-beams configured into a "tee pee" or "dolphin," was flattened and now lies bent over on the bottom.  Similar wave conditions can be presumed at the other locations as well (except the deep reef (40-60')).  Thus, we feel the reef faired pretty well even with the strenuous physical forces of the hurricane.  Other anecdotal reports (speaking to some local dive operators) indicate that there may have been more significant physical damage at other locations in the Marathon (Middle Keys) area.  This should be investigated further.
> 
> Larry took several rolls of wide angle photos at each location (print and slide).
> 
> George Garrett
> Director of Marine Resources
> Monroe County, Florida
>