[Coral-List] Cold Florida water

[Lauren Batte]

Melissa, Below is a recent press release related to your question.
Lauren
___________________________________________

Scientists Identify Important Source of
Nutrients to Florida's Coral Reefs

FOR IMMEDIATE RELEASE
July 24, 2003

CONTACT INFORMATION
Dr. James Leichter
Scripps Institution of Oceanography
(858) 822-5330 jleichter at ucsd.edu

Dr. Steven Miller
NOAA's National Undersea Research Center
University of North Carolina at Wilmington
(305) 451-0233 millers at uncw.edu

UNCW professor teams with Scripps and UC-Berkeley scientists to identify

important source of nutrients to Florida's coral reefs

Key Largo, Florida -- Coral reef scientists were surprised to learn that
the
deep ocean is the source of 20-40 times more nitrogen and phosphorus on
the outer coral reef than nutrient pollution from sewage and storm water

runoff.

A new study published this month documents a large and not previously
quantified source of nutrients to the coral reefs of the Florida Keys -
the deep
ocean. Lead author Dr. James Leichter, Scripps Institution of
Oceanography,
said, "We studied upwelling of cool, subsurface water at multiple sites
along
the Florida Keys reef tract. Our results show that this natural source
of
nutrients can deliver as much as 20-40 times more nitrogen and
phosphorus
to the outer reef tract than estimates of nutrient pollution from sewage
and
storm water runoff."

While these numbers are remarkable it's important to provide context.
Coauthor
Dr. Steven Miller, University of North Carolina at Wilmington, added,
"I'm sure some people will try to use these numbers to claim that
changing
sewage disposal practices in the Keys is unnecessary, but they would be
wrong. What our results show is that a major nutrient pump exists
offshore.
However, nothing in our study contradicts the fact that we also have a
nearshore pollution problem."

The study was published this month in the journal Limnology and
Oceanography and was a collaboration among scientists from
ScrippsInstitution of Oceanography, the University of California at
Berkeley, and the
University of North Carolina at Wilmington (UNCW). Much of the work
conducted during this study utilized saturation diving and the NOAA
Aquarius
underwater laboratory in Key Largo.

"What I like about this study is that it provides a balanced approach to
a
complicated issue. They acknowledge that while upwelling is a
significant
source of nutrients to the offshore reefs, they don't dismiss the need
to
better understand the dynamics of nearshore nutrient pollution making
its
way offshore," said Dr. Brian Keller, science coordinator for the
Florida Keys
National Marine Sanctuary.

The large amounts of nitrogen and phosphorus are brought to the reef by
an
oceanographic process called upwelling, in this case a specific, high
frequency form of upwelling caused by internal tidal bores. Leichter
explained, "It's a little like waves sloshing back and forth in a
bathtub, but in
the ocean at much grander scales and in ways that sometimes cause surges

of deep water to move into much shallower areas. When this happens in
the
Keys, nutrients brought to the reef can increase 10 to 100 times over
background levels."

The upwelled water is rich in nutrients due to natural processes. When
plankton and other organisms produced or living in surface waters die,
they
often sink to the bottom. Leichter further explained, "As these
materials sink,
they start to break down, they get eaten and excreted, and the end
result is
the slow and continuous addition of nitrogen and phosphorus to waters
with
increasing depth."

Interestingly, the upwelled water makes it to the reef a lot more often
than
people realize, sometimes several times a day. "The presence of this
water
on the reef for extended periods of time has the potential to
significantly
affect the biology of corals, sponges, and algae," added Leichter.
"This study illustrates the importance of assessing water quality over
different time scales," said Dr. Joe Boyer of Florida International
University.
Boyer manages the largest and longest running water quality monitoring
program in south Florida. "Our sanctuary-wide, quarterly monitoring
efforts
occasionally pick up these events, but are not designed to quantify this
type
of detail," he added.

Another important result of the study documents that a special form of
nitrogen in the upwelled water is also present in samples of algae
collected
from the reef. This part of the work, led by Hannah Stewart, University
of
California - Berkeley, suggests that the algae are directly using
nitrogen from
the upwelled water. "This is particularly interesting because some
scientists
believe that this special form of nitrogen is a sewage signal - a
smoking gun
- for pollution, while our work clearly suggests otherwise for the
offshore
reefs," added Miller.

These results are the culmination of work first started in the early
1990s,
initially with single deployments of oceanographic equipment that
detected
the surprising frequency and intensity of the upwelling events, and
later with
equipment deployments throughout the Keys to document the regional
significance of these events. "While our study focused on a large
natural
source of nutrients for the Florida Keys reef tract, things like coral
disease,
global warming, and overfishing are also important. The impacts of
humans
in this system are clearly dramatic and complex. That's why it's
important to
accurately assess variability in this system that is a normal part of
the system," added Leichter.

The paper by James Leichter, Hannah Stewart, and Steven Miller, is
titled
"Episodic nutrient transport to Florida coral reefs" (Limnology and
Oceanography Vol 48:1394-1407) and is available free at
http://aslo.org/lo/
toc/vol_48/issue_4/1394.pdf.

This research was funded by NOAA's National Undersea Research Center at
the University of North Carolina at Wilmington (UNCW). The Aquarius
underwater laboratory is owned by NOAA and is managed by UNCW
(www.uncw.edu/aquarius). Director UNCW National Undersea Research Center

For more information, contact:
Steven Miller
millers at uncw.edu

7/25/03 1:25 PM Environmental News Network - ENN Direct

Melissa Keyes wrote:

>   Hello Listers,
>
>   Many florida divers I know have been comenting for
> several weeks that there's a ferocious thermocline, at
> 50 feet and deeper, and the deeper water has been as
> cold as 55*f.
>
>   The beginning of lobster season for some was very
> successful, as the bugs are just kind of sitting
> around.  In some places normally active fish have been
> laying on their sides on the bottom.
>
>   Has there been any noticeable effect on corals in
> that area?
>
>   Is there a theory as to what's causing this?  Is it
> related to the very warm anomally in the North-eastern
> Atlantic several months ago?
>
>   One friend said it's because "Hell is finally
> freezing over."
>
>   Please forgive my *'measures.
>
>   Cheers,
>
>   Melissa Keyes, s/v Vinga
>
>
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