Black Water killing Coral

[Precht, Bill]

Dear Coral List:

This is the most recent news flash on the ongoing "black water" event in
south Florida.  From this its hard to see where the science starts and the
hype ends and visa versa.

None the less, the event whether natural or man induced (or enhanced) is
disturbing.

William F. Precht, P.G.
Ecological Sciences Program Manager
PBS&J
2001 NW 107th Avenue
Miami, FL  33172
305-592-7275
fax:305-594-9574
1-800-597-7275
bprecht at pbsj.com

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Divers find evidence of black water's devastation

Monday, April 1, 2002   Naples Daily News
http://www.naplesnews.com/02/04/naples/d485365a.htm

By CATHY ZOLLO, crzollo at naplesnews.com

Dead and dying sponges crumbled in Ken Nedimyer's hand as he made his way
along the bottom of the Northwest Channel off Key West last week.

Nearby, brain corals had recently died or were dying as well, the tiny
animals that build the corals decaying in their chambers. Not everything was
affected, but other corals normally golden brown had an odd white crust on
them, Nedimyer noted last week and in dives over recent days since black
water from the Southwest Florida coast bathed the keys.

"I've seen these corals under every imaginable circumstance, from 55 degree
water to 90 degree water, from calm, clear sea conditions to rough cloudy
conditions, and I've never seen them look quite like this," Nedimyer said.

He's been diving the keys since the 1970s, collecting sea life for his
business and growing heartsick over the declining state of the coral reefs
while doing it. He's seen the effects of an explosion in coral diseases and
the impact of human activity all around the reefs. Entire sections have been
nearly stripped of live corals and taken over by algae.

What he's seen since the black water moved through the keys depresses him
even more and has him wondering how long he'll be in business. He may not be
alone.

The Keys supports a $1.3 billion tourism industry that attracts about 3
million visitors each year, who come to snorkel, dive, fish and relax.
Annual commercial landings of fish are valued at roughly $50 million.

Though commercial fishermen reported scant catches of Spanish mackerel and
kingfish this season, landing numbers won't be available for six months,
fisheries officials said Friday.

First spotted by fishermen in January, the black water looked from satellite
pictures to have trailed in along the west coast of Florida late last year
and intensified when it reached western Florida Bay off the Shark River just
below Marco Island and Naples. It now sits atop the lower half of the island
chain as it dissipates.

By the time it reached the 126-mile chain of islands, the black water had
become diluted to about a 10th its intensity, according to fishermen who
first reported the water in January.

Divers out to assess its impact last week said it hadn't yet hit reefs south
of the chain that are most popular with tourists but appeared to be heading
there.

Nedimyer said in visits to dive sites up and down the Keys this week, he saw
similar recent effects where the water had moved through. Sea urchins seem
unharmed by the phenomenon but starfish, including the common serpent star,
were gone in the areas he dived. In a normal dive it's easy to find 50 or
more, but in four dives last week, he found one and it was dead.

Half or more of some sponge species - animals that filter quarts of water
per hour as they feed - were dead after the black water moved through.

"I also saw dead vase sponges, 'stinker' sponges, red and yellow ball
sponges, and red tree sponges," Nedimyer said in a report of a March 22 dive
trip.

Erich Mueller, head of Mote Marine Laboratory's Tropical Research Center in
Summerland Key, was also out on the water last week and noted that some
water was beautiful blue compared to the churned up olive green of the
dissipating black water. Mueller couldn't get a good fix on what was
happening in the channel because of the current and what it might have
already swept away, but he said close monitoring is in order.

"Everything isn't dead down there," he said. "But that's not to say things
aren't affected. ... (Researchers) need to get out more."

Others, including backwater guides and fishermen, reported the water making
its way in and around the Keys as of Friday, killing bottom life but seeming
not to affect fish, birds and mammals.

While Keys residents were on the water assessing the black water damage,
state scientists and those from the University of South Florida generally
downplayed the significance of the algae bloom that likely caused it at a
meeting in St. Petersburg on Thursday.

Researchers who are still looking into the phenomenon noted that water
samples appear normal in most respects, and there have been no fish kills
associated with the water. They say it might be a natural phenomenon, much
like a 100-year flood.

Something that sounds similar to the black water was reported in a 1902
science journal that cited an 1878 ship's log detailing "cypress colored"
water in the same area that killed large numbers of fish, plant life and
corals.

But even if it is a once-in-a-lifetime natural event, Keys residents wonder
at the seemingly nonchalant response from state officials and others.

"I don't understand the state trying to ignore it," said Craig Quirolo,
founder and director of Marine Projects for Reef Relief, an environmental
watchdog group. "People are very concerned. We are getting a lot of calls in
our office from backwater guides who are seeing the downside of this."

Quirolo, who dove Friday for a look, described the water as putrid-looking
and murky, but the destruction in some areas is plain and even more apparent
on video footage.

"Even if these things happen on a natural basis, we're accelerating
everything with the nutrient loading we're doing," Quirolo said.

He was talking about agricultural and sewage runoff from mainland Florida
rivers that makes its way to the Keys via gulf currents and local pollution
from Keys septic tanks.

If scientists link all the data together, the Keys have seen more than 90
percent mortality of coral near the Keys since 1975, said coral expert Phil
Dustan, professor of biology at the College of Charleston in South Carolina
and science adviser for the Cousteau Society.

"The state doesn't want to discuss that," Dustan said.

Scientists at Thursday's meeting said discolored water is typical for the
area, though fishermen and pilots on the water for decades said they'd never
seen anything like it.

State officials also said there was no cause for alarm for boaters, divers
and fishermen, and that bottom communities can rebound in as little as three
years. Researchers are now spot-checking the bottom of the western bay from
Naples to Key West to see if the water did anything to aquatic life there.

The largest part of western Florida Bay, where the water was darkest and
remained for the longest time, is home to sea grass beds, soft corals, sea
whips, sponges and other bottom life that provide shelter for other aquatic
life.

State scientists and others are now scrambling to collect more water samples
and find samples that may have been inadvertently collected during sampling
expeditions out on other business when the black water was in the bay.

Though state officials say they knew about the phenomenon as early as
January, a concerted effort to determine its cause and effects wasn't
launched until late March and headed by the Florida Marine Research
Institute.

Dustan said some bottom-dwelling species will come back fairly quickly under
the right conditions but not all.

"Brain corals might grow a centimeter a year," he said. So a 24-inch brain
coral is about 60 years old. "A lot of corals grow slower than that."

Dustan has been studying Keys reefs for decades and echoed Quirolo, saying
the black water is a symptom of a much larger problem involving nutrients
and other pollutants being dumped in the oceans.

"There may be times when these blooms occur, and they may be a natural
event," he said. "But if you look at the emerging marine diseases on the
planet today and you start to look at the diseases in birds and mammals and
coral and all the various brown tides we've seen to date, there's only one
conclusion you can draw. The oceans are in a lot trouble and we're causing
it."

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