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Thank you all for giving me a chance to tell you a bit today about what we're doing at
St. Lucie Reef. This has been a project that was spurred on by Jeff Beal arriving at Harbor
Branch. He actually occupies an office over on the other side of Old Dixie Highway even
though he works for FWC. When he got here, he knew that I was working on coral health
in various different areas and said, "You have to see this site." And I told him,
"You mean there's corals there?" And he said, "Yeh." And I said,
"Well, they're not supposed to be." He said, "I know, but they are."
So, that spurred us on to start looking at this area, and it's just outside of St. Lucie
Inlet, just south of it a little bit. So this is a really interesting area. It's much farther
north than the thermal tolerances of most corals along the eastern seaboard of the U.S.
in fact, for about 24 species of corals, they are found to this inlet and not any farther.
There's a few species that are found north of this inlet, about three or four. Most of
those are things like Oculina and Cladocora - small bushy encrusting corals, so this is
kind of a threshold for many of the corals that are in the South Florida region.
There has been a number of people that have worked on this project. Thank you to all for
your help, you're a great team. And the Park Service in particular. This is part of a State
Park, the St. Lucie Inlet State Park, was really instrumental in helping us to think
about how to make the data that we were collecting useful in terms of regulatory management moving
forward, and Charles Jabaly at the park has really been instrumental with that.
So, we're right now experiencing release. And they make release decisions in a very
simple model here. Right now, we're experiencing a release of about 250 cubic feet per second,
so if you look at this chart here on the right hand side you'll notice that the maximum allowable
releases can be upwards of 3,000 to 7,000 cubic feet per second at any given time, so
this is a very moderate release that we're experiencing right now. It can be huge flushes
at certain times, and so you see these pulses of turbidity-laden fresh water extending out
of the Inlet and extending out and over the reef. Now, in most inlets in Florida as the
water comes out of an inlet, it turns south and flushes along whatever is present, so
it's coming right out and across the sites that we've established at St. Lucie Reef and
so the major question is when we go out there and the water looks like this. I'm there believe
it or not, because of these heavy discharges how is it impacting coral health in this region?
And we've selected two species, the Diploria clivosa, a common brain coral, and Montastrea
cavernosa, the Greater Star coral. These are the most dominant corals on this reef, and
this is not a reef that's built up by lots of accumulation of corals over time. Instead,
it's a relic-ed reef that has a veneer of corals that are encrusting across the top
of it, so most of them look like huge saucers that are attached to the bottom in this high
wave environment. We're looking at three main things to quantify
health of these corals: their gene expression, what genes they're turning on in response
to the stimuli that are present; the bacterial communities that are on their surface mucus,
so the same way we have bacteria that contribute to our health status, they have became that
contribute to their health status; and then the zooxanthellae are the small algae that
live within corals, and allow them to do photosynthesis and survive in areas where they may otherwise
not survive by feeding alone. In 2010, working with Jeff, we established
three sites that called North, Central, and South. We added the Ledge site in 2011, because
we saw some interesting things going on there in terms of fisheries use at that ledge site.
That's where you see big, goliath groupers come in during cold snaps. That's where you
see huge schools of tarpon over the top of the reef, and so we wanted to tie some of
the work we were doing to data that was being collected by other parts of FWC.
In 2011 we installed the little pendant HOBOs like Annie just showed you that can collect
temperature and light data. They work wonderfully. In 2012 we installed some salinity probes
that I'll talk about in just a moment. Essentially we've been targeting at least
two sampling events a year, correlating roughly with wet season and dry season. But when we
can add more than that, we do. Ideally, we'd be doing it quarterly, but this is a fairly
rough place to work. The only boats we have access to are up to about 22-feet, so when
it gets rougher than about three-foot seas, we can't get out there, and it's more common
than you would expect for this site. At each of these sites, we have five colonies
of each of those corals. With the exception of the North Site, there are no Montastrea
cavernosa at that North Site. Only the brain coral Diploria.
So, these onset salinity meters, they're called U24's. Initially they were marketed as a really
cost-effective tool to monitor salinity in ocean environments and in raceways and everything
else. Up until this point most salinity meters that could be deployed for a given amount
of time were in the five thousand dollar range. This one came along at $600. We snapped up
ten of them and said, let's give this a shot. We quickly found out there were some problems.
Number one, you can't calibrate them. You take end point measurements in situ of the
salinity and use that to fit your curve. If there's any drift or variance in between those
two endpoints, you don't capture it very well. Also, they were supposed to last three years
sampling once every minute. We set them to sample every fifteen minutes. They lasted
five months and nine of out ten of them died. We've had serious biofouling issues and most
sensors, like YSI sensors for example, YSI is a company that makes sensors, make anti-biofouling
kits that you can install on your sensors. If you install those kits on these sensors
it impedes their ability to be accurate, so you're stuck with a sensor that is likely
going to fail on your pretty soon. It gets biofouled very easily and doesn't generate
all that accurate data when it does get biofouled. So, I tasked my technician Moe, with looking
at a number of different measures of how well these were performing. We installed them next
to the LOBOs out here in the canal to see how they compared to a much higher end instrument,
and what you see is that the LOBOs - the one in yellow, most of them track fairly well
within their specified three percent tolerance range, but one of them failed completely,
couldn't even get it deployed. Three of the nine that were deployed didn't work very well
at all. So, my take-home message for this is "No-No
to HOBOs." We've also looked at bacterial community profiles.
Each of these individual dots represents the entire bacterial community that's on a given
coral, so dots that are very close to one another have similar bacterial communities.
Dots that are very far away from one another have very dissimilar bacterial communities.
What we found is that over time there's a lot of change, but there's no differences
among the sites that we were looking at. What's also interesting is that the bacteria
that we're seeing at St. Lucie Reef are very different from the bacteria that live on corals
in other parts of the Caribbean, so it's a unique location.
When we look at the gene expression profiles, it seems that site, rather than time, seems
to make more difference. We've seen things like elevated metabolism, tissue repair and
etcetera during the summertime when it's hot, but at the South Site, the site farthest away
from the Inlet, not the ones that are near the inlet, which is not what we expected and
this is from 2010. We're now processing the 2011 and 2012 data.
We've also been looking at the zooxanthellae. Take home message here: There's not a lot
of difference over time, or among site, but the two species have very different amounts
of zooxanthellae within their tissues, and one of my grad students, Courtney Klepac is
going to be looking at whether or not these zooxanthellae are actually shifting, because
we know different zooxanthellae have different physiological capabilities so we'll see which
ones are present and if they change over time. The reason this work is really important is
that it's setting a baseline for all these projects that are related to the Comprehensive
Everglades Restoration Plan. Here's a number of projects that are going
on in this region, and it's not by accident that this map that they developed doesn't
even show St. Lucie Inlet. Their entire scope of work is focused on the inlet and inward.
They have no work going on whatsoever outside of the inlet. So by doing this project, we're
hoping to fill a gap to understand how changes to this watershed are going to impact corals
that are just offshore. A few numbers to leave you with. We've done
some presentations at various different places. We have two publications, one that is ready
to be submitted; one that's almost ready to be submitted. We've supported a number of
students. We've been able to leverage a lot of various support, and right now we're working
on a Florida Sea Grant Proposal to expand this to not just to correlative work where
we look at how the water outflow affects the corals in the field, but to actually test
the effects of the estuarine discharge water on corals using mesocosms, so that's our next
step. Thank you.
[applause] [music]