Behind the scenes, and field work keeps RECON going strong
Shortly after 9:30 last Tuesday morning, Sanibel-Captiva Conservation Foundation Research Assistants A.J. Martignette and Jeff Siwicke departed from Tarpon Bay to check on two RECON sites.
About once a month during the summer, the research assistants conduct maintenance at their numerous RECON, (River, Estuary and Coastal Observing Network), sites to make sure the equipment is running smoothly. During the winter months it can be stretched a little longer because the fouling is not as bad due to it being weather dependent.
At least two sites are checked in one outing.
The first stop was at Redfish Pass, to deploy RECON sensor equipment, which recently came back from the manufacturer for its yearly service. Before it was deployed, Siwicke had redone the cage, treating it to protect it from corrosion, at the SCCF Marine Lab.
“The aluminum does not do well in the saltwater environment. You can’t use the same kind of anti-fouling measure paint on aluminum,” he said.
Martignette said there are two kinds of paint – copper base, and non-copper base. He said the problem is that copper is metal, and aluminum is a metal.
“When you have two dissimilar metals in contact in saltwater, one is going to corrode away. The copper paint can actually eat away at the aluminum metal,” he said, which basically destroys the cages.
Siwicke said he now takes all of the cages down to bare metal before applying an epoxy paint, which isolates it from the water. Then a copper-based paint goes on top.
“We figured out over the years that more time spent, the more care we take with the anti-fouling preparation, the longer we can leave them out there and get better data for longer periods,” he said.
When they were out in the field, before Martignette jumped into the water, they made sure the computer communicated with the sensor. Once everything was set to be deployed, he equipped himself with the correct tools to attach the cage under the water to the piling.
In addition, they checked the meteorological sensors for their weather station at Redfish Pass. The station includes an anemometer to measure the wind, a tipping bucket rain gauge, barometric pressure, temperature and humidity.
The weather station was made possible through a West Coast Inland Navigation District grant.
“These were the first, and may still be the only, weather stations that are located directly on the water in our area,” Martignette said. “These are giving true on water readings. We wanted the weather station for two reasons. One, we needed to know what the weather is because it helps explain water quality. If you have a big rain storm and the salinity drops, that’s probably why because freshwater is coming in. The other benefit is everyone can understand weather. Because it’s out there, it draws people to the website and we hope a few of those people look around at other parts of the website and get interested in water quality.”
The second stop of the day was at the Gulf of Mexico site, near Lani Kai on Fort Myers Beach.
When the duo pulled the cage out of the water, which had been out for about two months, a stone crab was found inside and released before they started troubleshooting why the sensor was not recording correctly.
Martignette said he knew they had a shutter issue at the site because of the data showing a low flat line.
“It was basically measuring the back of the barnacle and not the water,” he said. “Overall we have had pretty good luck with these shutters keeping fouling off, but if you have a barnacle starting in that one right spot it will block it. Once it can no longer turn, it’s no good.”
Martignette said although the cables had copper foil wrapped around them, it sometimes does not last in the saltwater, which revealed the growth of barnacles, leaving the shutter to one of the sensors open.
“We hope to get a year before we have to bring them back in and paint them. It depends on what site and it depends on if we painted it right before the summer and the fouling is bad verses if we painted it during the winter,” he said.
Siwicke began scrapping off the barnacles from the glass as carefully as he could using wooden toothpicks because they do not scratch the glass. Alcohol was also sprayed onto the glass to help clean the surface.
“The tricky part is there is a plastic, like glass window under there that you don’t want to gouge,” Martignette said. “The good thing is the refractivity of water in the plastic are very similar, so when it’s in water, small scratches kind of disappear.”
After the barnacles were removed, Martignette used his laptop computer to communicate with the sensor to make sure the shutter was able to open and close. Through some troubleshooting, it was determined that the sensor was sending data, but it was not responding to commands to close the shutter.
“We will have to swap that out before the next month’s service, otherwise it will be covered in barnacles again,” he said.
All of the barnacles on the cage are left alone because they had found when removed they take the paint with them. If the barnacles are in the way, they strategically remove them.
Before the cage was put back in the water, Siwicke cleaned another portion of the equipment, which includes an intake that sucks water in before shooting it through a tube. He used lab grade detergent and a mild bleach mixture.
“It happens monthly to keep the guts clean,” he said.
Martignette said when the water is sucked in it pulls it over a temperature sensor before going through a conductivity cell and applying an electrical current.
“Based on how much electricity makes it from one end to the other, it can calculate the salinity of the water,” he said through an equation. “There’s a dissolved oxygen sensor, which measures how much dissolved oxygen is in the water. There is a pressure sensor on the outside that measures the pressure, so we know how deep it is.”
Turbidity, how stirred up the water is, as well as how much reflection there is, is also measured. Chlorophyll, or how much plankton is in the water, is another measurement. Colored, dissolved organic matter is also measured, Martignette said, which is basically the brownness of the water.
“For almost every case it’s terrestrial produced. It’s when rain falls on dirt and leaves and picks up that color. Generally high CDOM water is fresh water because it’s run off the land,” he said.
The men do the majority of their work at the SCCF lab to get the cage, and sensors ready to be deployed in the field.
“When we bring a unit in, I clean it up, make sure all of the sensors are cleaned up, so we can send it back to the manufacturer where they get calibrated and serviced. They are sent back to us and then I start from scratch and tape all of the instruments, prime them with anti-fouling paint. Then I put it all back together,” Siwicke said. “The cables don’t go in for service, but they get stripped down and get re-tapped.”
The equipment is sent back to the manufacturer roughly every 12 to 16 months to get serviced.
There are currently seven sites for RECON – Redfish Pass; McIntrye Creek; Tarpon Bay; Gulf of Mexico; Shell Point; Fort Myers and Beautiful Island. SCCF has nine sets of instruments, enabling one to be worked on and prepped for deployment, while the other is being serviced by the manufacturer.
Beautiful Island is currently offline, due to SCCF waiting to receive the equipment back from the manufacturer. Martignette said that location, because of the summer, is all freshwater, making it the best location to be offline right now.
A phosphate, wet chemistry sensor, which is different from all of the current dry chemistry sensors, is hoped to be deployed by the end of the year. Martignette said the sensor has liquids that they need to change, which will make them more dependent on changing out the reagent on a precis schedule.
With the new sensor, the duo are in the process of figuring out how to attach it vertically. All of the other sensors are mounted horizontally.
“We have to make this stuff up as we go. We have to invent it,” Siwicke said of fabricating a way to put it on the outside of the cage.
Before it is deployed, they hope to work with Harbor Branch Oceanographic Institute, which has experience working with the sensor.
A wave buoy will also be deployed again in early 2018, near Blind Pass.
For more information, and real time weather, visit recon.sccf.org