Posts Tagged ‘tides’

UGA Skidaway Institute researchers complete ‘26 Hours on the Marsh’

July 30, 2014

Pitching a tent in the woods and fighting off mosquitos may not sound like logistics of a typical oceanography experiment, but that is how researchers at the University of Georgia Skidaway Institute of Oceanography completed an intensive, round-the-clock sampling regimen this month. The project, dubbed “26 Hours on the Marsh” was designed to investigate how salt marshes function and interact with their surrounding environment—specifically how bacteria consume and process carbon in the marsh.

The team set up a sampling station and an outdoor laboratory on a bluff overlooking the Groves Creek salt marsh on the UGA Skidaway Institute campus. The scientists collected and processed water samples from the salt marsh every two hours, beginning at 11 a.m. on July 16 and running through 1 p.m. July 17. By conducting the tests for a continuous 26 hours, the team can compare the samples collected during the day with those collected at night, as well as through two full tidal cycles.

The UGA Skidaway Institute team processes water samples at their outdoor laboratory. (l-r) Megan Thompson, John DeRosa (UGA Intern), Zachary Tait and Dylan Munn (UGA Intern.)

The UGA Skidaway Institute team processes water samples at their outdoor laboratory. (l-r) Megan Thompson, John DeRosa (UGA Intern), Zachary Tait and Dylan Munn (UGA Intern.)

“We wanted to be able to compare not only what is happening to the carbon throughout the tidal cycle, but also what the microbes are doing at high and low tides and also during the day and night,” said Zachary Tait, a UGA Skidaway Institute research technician. “So we had to have two high tides and two low tides and a day and night for each. That works out to about 26 hours.”

The research team ran more than 30 different tests on each sample. The samples will provide data to several ongoing research projects. A research team from the University of Tennessee also participated in the sampling program. Their primary focus was to identify the bacterial population using DNA and RNA analysis.

This sampling project is one of many the researchers conduct during the year. They use an automatic sampling system for most of the other activities. The automatic system collects a liter of water every two hours, and holds it to be collected and processed at the end of the 26-hour cycle. The team could not use the auto sampler this time for several reasons; the scientists needed to collect much more water in each sample than the auto sampler could handle and the auto sampler tends to produce bubbles in the water, so it is not effective for measuring dissolved gasses.

Megan Thompson supervises Dan Barrett (l) and John DeRosa, both UGA interns, as they process samples in a UGA Skidaway Institute laboratory.

Megan Thompson supervises Dan Barrett (l) and John DeRosa, both UGA interns, as they process samples in a UGA Skidaway Institute laboratory.

“The UT scientists wanted to conduct enzyme analysis as well as RNA and DNA tests on the samples, and for those, the samples must be very fresh,” said Megan Thompson, a UGA Skidaway Institute research technician. “You can’t just go out and pick them up the next day.”

About a dozen scientists and students were involved in the project, including Thompson, Tait, a group of undergraduate students completing summer internships at UGA’s Skidaway Institute and a similar group from UT. They split their time between the tent and outdoor laboratory on a bluff overlooking Groves Creek, and the UGA Skidaway Institute laboratories a mile away.

“It was an interesting experience, and I think it went very well,” said Thompson. “However, when we wrapped it up, we were all ready to just go home and sleep.”

“26 Hours on the Marsh” is supported by two grants from the National Science Foundation, totaling $1.7 million that represent larger, three-year, multi-institutional and multi-disciplinary research projects into salt marsh activity. These projects bring together faculty, students and staff from UGA’s Skidaway Institute, UT and Woods Hole Research Center. UGA Skidaway Institute scientists include principal investigator Jay Brandes; chemical oceanographers Aron Stubbins and Bill Savidge; physical oceanographers Dana Savidge, Catherine Edwards and Jack Blanton; and geologist Clark Alexander. Additional investigators include microbial ecologist Alison Buchan and chemical oceanographer Drew Steen, both from UT; as well as geochemist Robert Spencer from WHRC.

Scientists use underwater robots to excite students about science

March 3, 2014

Can underwater robots catch the imagination of middle and high school students and spark an interest in science, technology, engineering and mathematics? Researchers and educators from the University of Georgia’s Skidaway Institute of Oceanography and Marine Extension (MAREX) think so. They are creating an education program focused on autonomous underwater vehicles (AUVs), also called gliders or underwater robots.

The program, “Choose Your Own Adventure,” will capitalize on Skidaway Institute’s expertise with AUVs and MAREX’s extensive history of marine education. Skidaway Institute scientist and UGA faculty member Catherine Edwards, and MAREX faculty members Mary Sweeney-Reeves and Mare Timmons will direct the one-year project.

Catherine Edwards (center) demonstrates an AUV to Mary Sweeney-Reeves (left) and Mare Timmons.

Catherine Edwards (center) demonstrates an AUV to Mary Sweeney-Reeves (left) and Mare Timmons.

The AUVs are a cutting-edge technology in marine research. The torpedo-shaped vehicles can be equipped with sensors and recorders to collect observations under all conditions. They are launched into the ocean and move through the water by adjusting their buoyancy and pitch. Because they are highly energy-efficient, gliders can remain on a mission for weeks at a time. Every four to six hours over their mission, they surface, report their data by satellite phone and receive instructions as needed.

Skidaway Institute’s AUV, nicknamed “Modena,” has been used in several recent projects, including “Gliderpalooza,” a simultaneous, cooperative launch of 13 AUVs from different institutions in 2013.

“Gliders are education-friendly, but the existing outreach activities are stale,” said Edwards. “Our program will develop the next generation of AUV outreach programs by combining cutting-edge, interdisciplinary research with educational activities and strong STEM components.”

The proposed work will highlight the problem of working with the strong tides that are characteristic of the Georgia coast. A big issue in operating gliders there is developing a guidance and navigation system that will function well in that kind of environment. The fast-moving Gulf Stream, located roughly 100 miles off the Georgia beaches, also introduces navigation problems.

“Although the AUVs have Global Positioning Systems and can be programmed to travel a set course, tidal and Gulf Stream currents can exceed the glider’s forward speed, which can take the instrument off course and keep us from collecting data where we need it,” Edwards said.

However, on the education side, the predictability of tides makes the proposed program highly intuitive and education-friendly.

“Students who grow up and live on the water already have an intuitive sense of tidal currents,” said Timmons. “Students understand why currents change during certain phases of the moon. This coastal intuition will provide a foundation for us to start an innovative, hands-on approach to STEM activities.”

Activities will depend on grade level so middle school students will have different objectives than those in high school. However, all the activities will address the direction and speed the AUV travels to a destination. The AUV direction and speed will depend on the sea state of coastal waters such as strong currents, storms or high winds.

To address the problem of strong tides, Edwards and a team of Georgia Tech graduate students, co-advised by Fumin Zhang, have developed the Glider Environmental Network Information System, called GENIoS, which optimizes a glider’s path based on data from real-time observations and ocean models. Current doctoral students Dongsik Chang and Sungjin Cho are working to upgrade the system to integrate real-time maps of surface currents measured by Skidaway Institute radar systems.

The education plan is to involve two local educators, April Meeks and Ben Wells, who teach in the Savannah-Chatham County Public School System. Since the activities are multidisciplinary, their expertise in building math curriculum will be valuable as the team integrates concepts of marine science, math and engineering into classroom activities.

“After the initial planning phase, we will be taking the program on the road to Chatham County schools,” said Sweeney-Reeves.

Activities will include student role-playing as an AUV maneuvers through a playing field of vector currents on a large game board. Successful arrival at their destination depends on how the individual pilot responds to currents, wind and density changes in route.

“The real fun will begin when obstacles, like underwater volcanoes, a giant squid or other surprises, cause the pilot to reroute the course of the AUV,” said Sweeney-Reeves.

The activities will allow students to develop analytical skills in a program that will be compliant with Next Generation Science Standards for the 21st Century in the common core state curriculum.

The funded study will include two short glider deployments. A summer 2014 deployment will be used for field-testing, software validation and developing real-world scenarios for the outreach program. A fall deployment will serve as an opportunity for classroom participants to communicate with the glider in real time.

“We hope this one-year program will serve as a springboard for future funding and continued joint outreach by Skidaway Institute and Marine Extension,” said Edwards. “We’d love to develop computer games and apps for tablets and mobile phones that let students fly gliders through even more realistic scenarios based on the measurements we collect in real time.”

The program is being funded through a joint grant from Skidaway Institute, UGA Public Service and Outreach, and the UGA President’s Venture Fund. The UGA President’s Venture Fund is intended to assist with significant funding challenges or opportunities. The fund also supports small programs and projects in amounts typically ranging from $500 to $5,000.

For additional information, contact Catherine Edwards at 912-598-2471 or catherine.edwards@skio.uga.edu; Mary Sweeney-Reeves at 912-598-2350 or msweeney@uga.edu; or Maryellen Timmons at 912-598-2353 or mare@uga.edu.

 

Skidaway Institute scientists seek answers to salt marsh questions

January 2, 2013

Salt marshes are a vital part of the coastal ecosystem. They provide a nursery for many kinds of marine animal life. Sitting in the transition zone between the ocean and the land, salt marshes serve as a physical buffer against severe weather. They act as a chemical buffer by capturing, holding and releasing nutrients that are brought in on each tide. As a result, the marshes have a great influence on the type and amount of nutrients that enter the sounds and the ocean. That buffering capacity varies on tidal, daily and seasonal time scales, but how it functions is poorly documented.

A team of Skidaway Institute of Oceanography scientists have begun a project to get a clearer picture of how salt marshes function and interact with their surrounding environment.

The composition of the science team reflects the interdisciplinary nature of the project. Principal investigator Jay Brandes, Aron Stubbins and Bill Savidge are chemical oceanographers, and Catherine Edwards is a physical oceanographer. Geologist Clark Alexander and physical oceanographers Jack Blanton and Dana Savidge are also contributing to the effort. The three-year project is funded by a $699, 971 grant from the National Science Foundation.

The research team at Groves Creek (l-r) Clark Alexander, Jack Blanton, Catherine Edwards, Jay Brandes, Dana Savidge, Bill Savidge, Aron Stubbins

The research team at Groves Creek (l-r) Clark Alexander, Jack Blanton, Catherine Edwards, Jay Brandes, Dana Savidge, Bill Savidge, Aron Stubbins

“Scientists have looked at salt marshes in the past and have gotten some good data,” Brandes said. “However, this will be the first detailed look at the combined functions of one of these marsh systems.”

The project will focus on Groves Creek, a portion of coastal salt marsh along the Wilmington River, adjacent to the Skidaway Institute campus. Groves Creek has been the site of other research projects.  Over the past three years, Blanton, Alexander, Dana Savidge and others have studied the topography and water-flow in the marsh as part of a Department of Energy-funded project.  Because of this, the physical layout of the marsh has been documented to a fine detail.

“We already know a lot about this area, especially how the water moves in and out of the marsh on the tides,” said Brandes. “We have a very good understanding of the topography of the top of the marsh and its tidal creeks, both above and below the surface.”

The scientists also believe the Groves Creek area is fairly representative of salt marshes along the Georgia and South Carolina coasts.

From a chemical standpoint, the research will focus on way the salt marsh uses carbon: is it a consumer or producer of carbon-based organic material and nutrients?

“Marshes take material in from the river on every high tide, and they deliver material back to the river on the falling tide — but it isn’t the same stuff,” Savidge said. “The marsh changes the river chemistry on every tidal cycle.”

There isn’t much consensus on what controls that exchange between river and marsh. “That is one of the big questions,” said Brandes, “Trying to understand whether the marsh is a producer or consumer, and how that changes over time, the seasons, the tides and so on.”

To get a detailed history of marsh-river exchange, the scientists will place sensors in the marsh that will measure various conditions every 15 minutes. Remote sensors cannot measure everything, so the research team will also be collecting samples on a daily basis and returning them to their labs for analysis.  Understanding the big picture will come from adding up all the little incremental changes over time and relating them to the actions of sun, tide and weather on the marsh surface.

Stubbins will focus his efforts on the role of dissolved organic carbon in the marsh. Savidge will work look at how the salt marsh uses dissolved oxygen. Edwards will be modeling how water flows in and out of the system and how that movement interacts with the chemical and biological activity.

When the project is complete in three years, the Skidaway scientists expect to have a much more extensive picture of the role salt marshes play in the larger coastal ecosystem.

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