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Documentary Transcript
USGS
science for a changing world
Coral Reefs in Honduras: Status after Hurricane Mitch
[narrator]
Coral reefs around the world were severely affected by bleaching by a
large El Ni?o event in 1997 and 1998 and on October 25, 1998, coral reefs along the northern
coast of Honduras faced additional problems. Category 5 Hurricane Mitch had formed into the
fourth strongest Atlantic hurricane on record. It followed a slow, meandering path as waves
formed by the 180 mile per hour winds battered coral reefs and six feet of rain overflowed
rivers and inundated reefs with fresh water and sediment. By the time it had passed, over
11,000 people were dead and 2 million were homeless throughout Honduras, Nicaragua,
El Salvador, and Guatemala.
In response to this devastation, the U.S. Agency for International Development received funding
from Congress to provide assistance to countries devastated by Mitch. Part of this money was
allocated to the U.S. Geological Survey to study the impact of Hurricane Mitch on two coral reefs
directly hit: Cayos Cochinos Biological Reserve, which is located on the continental shelf
approximately 12 miles off the northern coast of Honduras, and Roat?n Marine Reserve,
located 18 miles north of Cayos Cochinos.
Cayos Cochinos is undeveloped but the surrounding waters are frequently turbid due to sediment
from river discharge off the Honduran coast. Roat?n is more developed but is generally free from
outside sediment sources. These differences enabled USGS scientists to study hurricane effects
on two different types of reefs that are in proximity to each other.
[Part 2]
[Bob Halley, USGS]
It became clear as soon as we got there on our first visit that the
Cayos Cochinos area was much more affected by Mitch than Roat?n, even though Roat?n was
closer to the hurricane when it was a very strong hurricane. It was not the winds and waves and
physical damage that affected the reefs; primarily it was the turbid water that came from
nearshore areas so that the inshore reefs in Cayos Cochinos were much more affected by the
turbid waters that came off after the flooding.
[narrator]
In order to measure the effects of the flooding, instruments that measure light,
temperature, and salinity were installed at both reefs at a depth of 17 feet. Generally, river runoff
lowers salinity levels and carries soil and debris that reduces the amount of light that the coral reef
receives. This inhibits photosynthesis, increases nutrient levels that can trigger algal growth, and
stresses the coral. One river in particular, the Aguan River, generated a plume of water large enough
to inundate Cayos Cochinos and Roat?n and to influence other reefs far out in the Caribbean.
[Bob Halley]
The major effect that we saw was on our first trip, which was about a year
after the hurricane, there were abundant coral diseases. In fact, we were sort of taken aback with
the amount of a particular disease - black band disease - that seemed to just be everywhere.
[narrator]
Coral disease was not alone in impacting the reefs. Prior to Hurricane Mitch,
some of the highest water temperatures ever recorded in the Caribbean were impacting the reefs,
causing coral bleaching. To monitor post-Mitch water temperatures, an additional instrument that
measures only temperature was installed at 3 different areas in the Cayos Cochinos Biological
Reserve: Lion?s Head at a depth of 17 feet, Pelican Point at a depth of 66 feet, and a reef near the
project?s field station at a depth of 3 feet.
[Bob Halley]
Coral bleaching occurs usually in the late summer when water temperatures
reach their annual extremes and, if they are high enough, it so stresses the coral that they expel
the algae that live symbiotically in their tissues (it?s what gives the coral their color) and when they
do that the corals turn absolutely white. They can exist that way for maybe 6 or 8 weeks and
recover but if the bleaching persists longer than 2 months there is an amazing amount of fatality
associated with it.
[Part 3]
[narrator]
Hurricanes affect coral reefs in many ways. Pounding waves inflict direct
physical damage. And sediment runoff from flooded rivers causes acute stress in coral reef
organisms. There are also beneficial effects, such as the breaking and distribution of coral
fragments that start new colonies and the cooling of high water temperatures.
[Bob Halley]
As with any large hurricane, Hurricane Mitch had a tremendous amount of
upwelling associated with it where cooler, deeper ocean waters are brought to the surface by the
mixing that the hurricane induces.
Hurricane Mitch actually reduced the water temperature by more than a degree. That may not seem
like much, but often a single increase of a degree or two when the water temperature is already
warm is enough to induce bleaching. So, while Hurricane Mitch did some damage and caused a fair
amount of disease for a few years, it prevented a bleaching episode that evidently killed as much as
50% of the live coral in some other areas of the Caribbean in September of 1998.
Each visit we made subsequently to our first visit we saw less and less coral disease and we thought,
perhaps, the difference in less disease was just seasonal, but by the Fall of 2000, when the water
warmed back up again, there was not an associated increase in disease. The amount of disease
continued to decline so we think it was a real shift in just improvement of the reef over the two
years we were there.
[Part 4]
[narrator]
Very little reef data existed in this area prior to Hurricane Mitch so continued
monitoring is essential in order to understand the long-term impacts that major storms, high water
temperatures, sediment runoff, and low salinity events have on coral reef health.
[Bob Halley]
We have made arrangements with our colleagues on Cayos Cochinos at the
research station to continue to maintain this instrumentation with two goals in mind: 1) we will get a
longer record which will help us differentiate what is a local and what is a more regional signal and
2) in any given year late in the hurricane season they may experience another hurricane and so
we would very much like to see what kinds of data these instruments collect if another significant
hurricane impacted the region.
Produced and Edited by:
Tim Holmes
Narration by:
Terry Edgar
Video Provided by:
Ginger Garrison ? USGS
Bob Halley ? USGS
Don Hickey ? USGS
Thomas Michot ? USGS
Chris Reich ? USGS
Still Imagery Provided by:
Aerofoto Centro Americana
Air Force Open Skies Program of the Defense Threat Reduction Agency
Defense Mapping Agency
Earth Scan Laboratory, Coastal Studies Institute, Louisiana State University
NASA ? Earth Sciences & Image Analysis, Johnson Space Center
National Center for Atmospheric Research (NCAR)
NOAA Geophysical Fluid Dynamics Laboratory (GFDL)
NOAA Magazine
NOAA Office of Satellite Data Processing and Distribution (OSDPD)
NOAA Operational Significant Event Imagery
NOAA National Climatic Data Center
University of Wisconsin ? Madison Cooperative Institute for Meteorological Satellite Studies (CIMSS)
University of Wisconsin ? Madison Space Science and Engineering Center
USGS Center for Integration of Natural Disaster Information (CINDI)
Special Thanks To:
Steven Carson ? NOAA GFDL
Neal Dorst ? NOAA AOML
Ginger Garrison ? USGS
Peter Grimm ? NOAA
Bob Halley ? USGS
Don Hickey ? USGS
Bob Jubach - NOAA
Frank Lepore -NOAA
Mary Matta ? NOAA
Thomas Michot ? USGS
Jeff Phillips ? USGS
Edward Proffitt ? USGS
Chris Reich ? USGS
John Sheldon ? NOAA GFDL
Mark Smith - USGS
John Walkey ? USGS
The Honduras Coral Reef Fund and Cayos Cochinos Reserve:
Adoni Cubas
Carlos Garcia-Saez
Elias Aquilar Gonzales
The Roatan Institute for Marine Sciences:
Julio Galindo
Jennifer Keck
Contact:
Bob Halley
rhalley@usgs.gov
Don Hickey
tdhickey@usgs.gov
Chris Reich
creich@usgs.gov
USGS
Center for Coastal and Regional Marine Studies
600 Fourth Street South
St. Petersburg, FL 33701
727-803-8747
http://mitchnts1.cr.usgs.gov/projects/coral.html
USGS
science for a changing world
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