Tag Archives: science

UGA Skidaway Institute researchers probe complex Atlantic Ocean currents

Dana Savidge

The ocean off the coast of North Carolina has a complex system of ocean currents that make it one of the least understood areas on the U.S. Eastern Seaboard. University of Georgia Skidaway Institute of Oceanography professor Dana Savidge is leading a team of scientists, including UGA Skidaway Institute scientist Catherine Edwards, working to unravel the mysteries of the complex ocean currents near Cape Hatteras.

The four-year project, informally called PEACH: Processes driving Exchange At Cape Hatteras, was launched in early 2016 and is funded by a $5 million grant from the National Science Foundation to better understand the relationship between the waters of the continental shelf and the deep ocean.

“The U.S. continent, like others, has a shallow ocean immediately around it, called the continental shelf. It’s like an apron that extends out from the shoreline and it is fairly shallow, only about 60 meters deep,” Savidge said. “At its outer edge, the bottom drops sharply into the deep ocean, which can be miles deep.”

Exchange at the shelf edge can push cold, nutrient-rich water from the deep ocean onto the shelf, which drives productivity of marine algae and the food web that it supports.

“There’s a reason people love offshore fishing at the edge of the Gulf Stream,” said Edwards. “Areas with regular exchange of shelf and deep waters are often known hot spots for commercial and recreational fishing.”

One reason Cape Hatteras attracted the researchers’ attention is that two opposing deep ocean currents collide there, making the ocean there highly dynamic. The warm Gulf Stream hugs the edge of the continental shelf as it flows north from the tip of Florida. At Cape Hatteras, the Gulf Stream opposes a colder current, the Slope Sea Gyre current, that moves southward along the mid-Atlantic coast. There, the Gulfstream breaks away from the coast toward northern Europe.

There is a convergence of shelf currents at Cape Hatteras as well, as cool shelf waters of the mid-Atlantic continental shelf meet the warm salty shelf waters from the south. Each of these currents, on the shelf and at the shelf edge, has a distinct temperature, salinity, and often a biological signal that reflects the origin of the water it carries. The team will measure these properties and ocean currents to better understand the exchange processes.

During the first year of the study, the researchers prepared and installed a network of sophisticated, high-tech instruments on the shore and in the ocean to monitor and capture the movement of water and changing properties like temperature and salinity. Together with scientists from the University of North Carolina and North Carolina State University, the team has worked with ocean models to better understand the interaction between shelf currents and the deeper currents of the Gulf Stream and the Slope Sea Gyre.

“Circulation on the continental shelf and the deep ocean can be quite separate things, but their effects on one another can be quite complicated,” Savidge said.
In addition to subsurface packages moored on the sea floor, the PEACH team is taking advantage of modern sampling techniques with shore-based radar systems and autonomous underwater vehicles called gliders to collect data remotely.

Savidge working on a radar antenna on the Outer banks.

Savidge’s hardware contribution to the project is a series of low-power, high-frequency radar stations that scan the waters of the continental shelf and measure the speed and direction of surface currents.

“Measuring surface currents remotely with the radars is a real advantage here,” Savidge said. “They cover regions that are too shallow for mobile vehicles like ships to operate, while providing detailed information over areas where circulation can change quite dramatically over short times and distances.”

An array of radar antennae on an Outer Banks beach.

Savidge’s research technician, Gabe Matthias, installed the radar systems on the beach at Salvo and Buxton, and at the airports at Frisco and Ocracoke, North Carolina. Currently, the researchers are working out the bugs in the system and getting the four stations to work together to paint a composite picture of the surface currents. The radars produce a massive amount of data to be processed.

Edwards leads the effort to use gliders that will operate on the shelf for nearly the entire 16-month experiment. Gliders are shaped like torpedoes and equipped with sensors to measure properties like temperature, salinity and dissolved oxygen. They can be programmed to cruise the underwater environment for weeks at a time, surfacing at regular intervals to transmit its collected data via a satellite phone.

Edwards in her lab with a glider.

Edwards’s specialty is improving the way these gliders sample the coastal waters using information from models and real-time data streams, including surface currents from Savidge’s HF radar. Edwards and doctoral students Qiuyang Tao and Mengxue Hou, co-advised by Edwards and Fumin Zhang of Georgia Tech, have developed new systems that optimize the path of the gliders based on near real-time information about current patterns and how they are expected to change, making operations more efficient and allowing better data collection.

“The glider provides data that help explain how temperature, salinity, and density change in space and time underwater, and the HF radar provides high resolution maps of surface currents every 20 minutes,” said Edwards. “The two systems are highly complementary, and their combination provides an unprecedented view of when, where, and why there is exchange between the shelf and deep ocean.”

According to Savidge, the study should produce a greater understanding of the forces at work at Cape Hatteras with implications across a wide range of interests from fisheries management to pollution control. Microscopic marine plants, known as phytoplankton, are a vital part of the marine ecosystem. Phytoplankton are the very base of the marine food web and they produce approximately half the oxygen in the atmosphere. In addition to tracking deep water inputs that support productivity on the shelf, Savidge said, it would is also be important to understand any processes that transport carbon-rich shelf water back to the deep ocean. When phytoplankton and the rest of the food web convert nutrients into their own biomass, water returned to the deep ocean can carry large quantities of organic carbon with it.

The knowledge gathered at Cape Hatteras will be applicable to other oceans around the world.

“Cape Hatteras is the ideal place to look at these processes that you are going to find elsewhere,” Savidge said. “You have a lot of energetic forcing and everything is concentrated in a very small space, with large variations over short distances. The idea is to understand the processes so you can model them effectively. If you can do that, you can anticipate how circulation on the shelf and exchanges with the deep ocean will respond to changes in the Gulf Stream or the wind over time.”

The project will run through March 2020. The other members of the research team are Harvey Seim and John Bane of the University of North Carolina; Ruoying He of North Carolina State University; and Robert Todd, Magdalena Andres and Glen Gawarkiewicz from Woods Hole Oceanographic Institute.

Savidge expressed special appreciation to the National Park Service and the North Carolina Department of Transportation for providing sites for the radar installations, and the University of North Carolina’s Coastal Studies Institute for help in installing them.

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UGA Skidaway Institute scientists study microbial chemical warfare

In the battlefield of the microbial ocean, scientists have known for some time that certain bacteria can exude chemicals that kill single-cell marine plants, known as phytoplankton. However, the identification of these chemical compounds and the reason why bacteria are producing these lethal compounds has been challenging.

Now, University of Georgia Skidaway Institute of Oceanography scientist Elizabeth Harvey is leading a team of researchers that has received a $904,200 grant from the National Science Foundation to fund a three-year study into the mechanisms that drive bacteria-phytoplankton dynamics.

Researcher Elizabeth Harvey examines a part of her phytoplankton collection.

Understanding these dynamics is important, as phytoplankton are essential contributors to all marine life. Phytoplankton form the base of the marine food chain, and, as plants, produce approximately half of the world’s oxygen.

“Bacteria that interact with phytoplankton and cause their mortality could potentially play a large role in influencing the abundance and distribution of phytoplankton in the world ocean,” Harvey said. “We are interested in understanding this process so we can better predict fisheries health and the general health of the ocean.”

A microscopic view of a population of phytoplankton.

This project is a continuation of research conducted by Harvey and co-team leader Kristen Whalen of Haverford College when they were post-doctoral fellows at Woods Hole Oceanographic Institution. They wanted to understand how one particular bacteria species impacted phytoplankton.

“We added the bacteria to the phytoplankton and the phytoplankton died,” Harvey said. “So we became very interested in finding the mechanism that caused that mortality.”

They identified a particular compound, 2-heptyl-4-quinlone or HHQ, that was killing the phytoplankton. HHQ is well known in the medical field where it is associated with a bacterium that can cause lung infections, but it had not been seen before in the ocean. The team will conduct laboratory experiments to determine the environmental factors driving HHQ production in marine bacteria; establish a mechanism of how the chemical kills phytoplankton; and use field-based experiments to understand how HHQ influences the population dynamics of bacteria and phytoplankton.

“This project has the potential to significantly change our understanding of how bacteria and phytoplankton chemically communicate in the ocean.” Harvey said.

The project will also include a strong education component. The researchers will recruit undergraduate students, with an effort to target recruitment of traditionally under-represented groups, to participate in an intense summer learning experience with research, field-based exercises and some classroom work.

“The idea is for the students to return to their home institutions at the end of the summer, but to continue to work with us on this project,” Harvey said. “This will be a unique opportunity to offer students cross disciplinary training in ecology, chemistry, microbiology, physiology and oceanography.”

In addition to Harvey and Whalen, the research team includes David Rowley of the University of Rhode Island.

Skidaway Institute adds to fleet

UGA Skidaway Institute has added its newest and smallest research vessel to its fleet. Researcher Clark Alexander’s team is in the process of configuring a new shallow water survey boat to enhance its capabilities for collecting high-resolution bathymetric data. new-boat-1-w

Hydrographic surveys in shallow environments present challenging logistical situations.  The new Hydrographic Survey Launch will greatly extend the range of tides and conditions available for survey missions. The launch is 10 feet long and will be equipped with a Knudsen Mini-Sounder single-beam sonar, a dual head GNSS GPS system, an inertial motion sensor  and a waterproof touchscreen computer.

UGA Skidaway Institute develops cutting-edge microbial imaging laboratory

A team of researchers from the University of Georgia Skidaway Institute of Oceanography has received a $226,557 grant from the National Science Foundation to acquire state-of-the-art imaging equipment to investigate microorganisms from the tiniest viruses to larger zooplankton. The equipment will be housed in UGA Skidaway Institute’s new Laboratory for Imaging Microbial Ecology, or LIME.

Researcher Elizabeth Harvey leads the research team that also includes UGA Skidaway Institute scientists Julia Diaz, Marc Frischer, James Nelson and James Sanders.

UGA Skidaway Institute researchers Tina Walters, Marc Frischer and Karrie Bulski practice running zooplankton samples on the FlowCam, a new instrument that is part of LIME

UGA Skidaway Institute researchers Tina Walters, Marc Frischer and Karrie Bulski practice running zooplankton samples on the FlowCam, a new instrument that is part of LIME

The equipment will improve Skidaway Institute’s capability to conduct field and laboratory experiments by automating many viewing methods.

“Anyone who uses a microscope will tell you that it is both tedious and time consuming,” Harvey said. “This equipment will allow us to enumerate and analyze microbes and other planktonic organisms much faster, and will allow us to do more large-scale projects than we could in the past.”

Microscopic phytoplankton photogaphed in the LIME.

Microscopic phytoplankton photogaphed in the LIME.

Much of the equipment will also have imaging capability so researchers will be able to do more detailed measurements on the size and shape of the tiny organisms and how that might relate to the health of an ecosystem.

Marine microbes are an essential component of all marine ecosystems and they play central roles in mediating biogeochemical cycling and food web structure.

“They are the things that drive all other processes in the ocean,” Harvey said. “They play a really important role in the way nutrients, oxygen and carbon are cycled through the ocean. We care a lot about those processes because they impact our climate, fisheries and the ocean’s overall health.”

The benefits of LIME will be shared beyond Skidaway Institute’s science team. Harvey envisions it as a regional center for microbial imaging, available to any other researchers who need the capability.

“Anyone is welcome to come here and get trained to use them,” she said. “They just need to contact me and we can make arrangements.”

Some of the equipment is already in place, while other pieces have not been delivered. Harvey anticipates all the equipment being functional by mid-2017.

UGA Skidaway Institute associate professor cited for top research articles

University of Georgia Skidaway Institute of Oceanography associate professor Aron Stubbins is one of just a handful of researchers cited in the journal Limnology and Oceanography for authoring two of the journal’s top scientific papers over the past 60 years.OLYMPUS DIGITAL CAMERA

Limnology and Oceanography is an official publication of the Association for the Sciences of Limnology and Oceanography and is considered a premier scientific journal. In its recently published 60th anniversary issue, the journal collected and republished the 10 most cited research papers for each of the last six decades. Stubbins authored or co-authored two of those papers, one in 2008 and the other in 2010.

“It came as quite a surprise to see two articles show up on the list,” Stubbins said. “I was at a conference and wasn’t really checking my email when one of my colleagues let me know.”

The journal used the number of times a paper was cited in future studies as the yardstick to determine which papers should be included on the list. It is one commonly used method for measuring the impact of a scientist’s work.

“The list isn’t really about popularity,” Stubbins said. “It’s about usefulness. That people have found some of my work useful over the years is rewarding.”

The 2008 paper was titled “Absorption spectral slopes and slope ratios as indicators of molecular weight, source, and photobleaching of chromophoric dissolved organic matter.” The lead author was John Helms. Stubbins was a co-author along with four other scientists. The research team developed a new method for extracting new information from a relatively common and simple test of the color of dissolved organic matter.

Stubbins was the lead author, along with nine co-authors, of the second paper, “Illuminated darkness: Molecular signatures of Congo River dissolved organic matter and its photochemical alteration as revealed by ultrahigh precision mass spectrometry.” The study examined organic carbon carried to the ocean by the Congo River — after the Amazon, the second largest river in the world in terms of carbon and water flow. The research team studied how sunlight degrades organic material, including which compounds are degraded, which are not and what new compounds are created when sunlight shines on river water.

“His inclusion in this seminal volume is quite an honor for Dr. Stubbins,” UGA Skidaway Institute Interim Director Clark Alexander said. “This recognition validates what we have always known, that he is conducting groundbreaking and meaningful research that is recognized around the world.”

All 60 papers can be found at http://aslopubs.onlinelibrary.wiley.com/.

 

UGA Skidaway Institute receives $79,000 gift to support marine research

Savannah residents Michelle and Barry Vine presented a gift of $79,000 to the University of Georgia Skidaway Institute of Oceanography to support the institute’s cutting-edge oceanographic research. In recognition of the gift, UGA Skidaway Institute plans to name an observation laboratory in honor of Michelle Vine’s father, Albert Dewitt Smith Jr. The Vines’ gift is the largest monetary donation ever given to UGA Skidaway Institute.

“We are pleased to support the UGA Skidaway Institute of Oceanography in its continuous effort to conduct research and protect our coastal environment,” said Michelle Vine. “Every day we enjoy the benefits of living on the coast, and as a community, we should never forget how important Skidaway Institute is to us.”

Michelle Vine presents a check to Skidaway Institute interim executive director Clark Alexander in front of the Roebling cattle barn.

Michelle Vine presents a check to Skidaway Institute interim executive director Clark Alexander in front of the Roebling cattle barn.

Vine’s father, Al Smith, was a World War II Marine Corps veteran, and, like his daughter, a UGA graduate.  He worked in industrial relations for General Motors in Doraville, Lockheed in Marietta and Union Camp Corp. in Atlanta and Savannah. For the last 12 years before his death in 1998, he owned Complete Security Systems.

The Albert Dewitt Smith Jr. Observational Laboratory will be located in the soon-to-be-created Center for Hydrology and Marine Processes. Earlier this year, the Georgia General Assembly approved a $3 million appropriation to renovate and repurpose a circa-1947 concrete cattle show barn for laboratory and meeting spaces and as a home for the center. Innovative for its time, the cattle barn was constructed by the Roebling family. The Roeblings established the Modena Plantation in the mid-1930s, and raised black angus cattle and Hampshire hogs before they donated their land to the state in 1967 to create Skidaway Institute.

“We are very grateful to the Vines for their generous gift,” said UGA Skidaway Institute Interim Director Clark Alexander. “This will help support our education and research activities, both here on the coast and around the world.”

“The UGA Skidaway Institute is a division of the University of Georgia, but it also relies heavily on local support,” Vine said. “Please join us by donating online at http://www.skio.uga.edu, and becoming a member of ASI, the Associates of Skidaway Institute.”

Letter from Jim Sanders

Dear Friends,

This is an exciting time for the University of Georgia’s Skidaway Institute of Oceanography and a critical moment in time for our ocean and its resources. Our faculty, staff and students are conducting world-class research, and we are making headway in understanding the processes that define the ocean and coastal ecosystems. Even after many years as the Institute’s director, I remain awestruck by the ingenuity and dedication of Skidaway’s scientists. Below, I highlight some of our recent efforts:

  • The National Science Foundation has just awarded Drs. Dana Savidge, Catherine Edwards and their colleagues funding to study the processes that drive water exchange (and the particles and organisms associated with the water) in the vicinity of Cape Hatteras.
  • Two new scientists have joined the Skidaway faculty: Drs. Elizabeth Harvey and Julia Diaz. Drs. Harvey and Diaz are examining how planktonic organisms interact with one another and how they influence their surroundings.
  • Dr. Aron Stubbins has been examining how changing climate, leading to loss of ice from glaciers and from permafrost, is altering carbon transport and utilization in Arctic ecosystems; while Dr. Cliff Buck and his colleague, Dr. Chris Marsay, are studying the flux of trace metals into and through that same region.
  • Many Skidaway scientists are focusing on processes and consequences of sea level rise, particularly its impacts on barrier islands and marshes, and how changes in salinity associated with increased inflow of ocean water into coastal rivers and creeks influences nutrient and carbon flows in coastal ecosystems.
  • Finally, in the coming year, state funds will help to repurpose the Institute’s iconic cattle show barn from the Roebling era into the Center for Coastal Hydrology and Marine Processes (CHAMP), with a focus on research and education directed toward understanding influences on coastal systems and the wise stewardship of coastal resources.

These examples underscore the importance of our work, and they are just a small part of the quiet, yet meticulous way we pursue our mission to advance understanding of coastal and marine environments.

That mission, in turn, is part of Skidaway’s larger vision — to continue as an international leader in interdisciplinary ocean research, developing and promoting collaborations in science, education, policy and public service. We work with scientists from around the nation and around the globe, and with students and scientists from elsewhere who are drawn to Skidaway to conduct their research. The international science community is well aware of Skidaway Institute’s research and its scientists. Our reputation has been built over nearly 50 years by quiet, yet fundamental, research and education.

Our success and reputation hasn’t happened alone, however; indeed, our efforts have been aided by the support of many. It has been your contributions to the Associates of Skidaway Institute that have allowed me to invest in valuable research and education pilot projects, and to support students, staff and faculty in their efforts. With your help, we have been able to reach out to the community to help with issues facing coastal resources; to support undergraduate and graduate students who wish to study here at the Institute; and to provide promising young faculty members with additional resources to answer urgent research questions. Please consider sending a contribution to support our future efforts — today!

I am very proud to have been a small part of Skidaway’s history, first as a graduate student in the 1970s, and more recently as its director. I am stepping down as executive director of Skidaway at the end of June, and assuming my faculty position. I do so with mixed feelings, because Skidaway Institute of Oceanography and its faculty, staff and students have been so important to me. However, it is time for new leadership, with new ideas, to drive Skidaway Institute of Oceanography to greater heights. That will ensure that we continue to attain our mission and vision; that we remain known for world-class science; and that we succeed in our efforts to create a more knowledgeable citizenry capable of promoting sound utilization of natural coastal and marine resources while capitalizing on coastal economic opportunities. Dodie and I will continue to support the Institute through the Associates, and I hope that you will continue to do so, as well. Your regular contributions are a critical component necessary for our success.

Thank you for everything that you have done to help me over the past 15 years.

Jim

Editor’s Note: The  Associates of Skidaway Institute is a branch of the University of Georgia Foundation, a 501(c)3 non-profit corporation. Most donations are tax-deductible. Donations to ASI are reserved for use by UGA Skidaway Institute. Donations can be made online by credit card. Click this link for additional information, membership levels and a link to a donation page: http://www.skio.uga.edu/?p=aboutus/asi.

Donations can also be made by check to:

Associates of Skidaway Institute

10 Ocean Science Circle

Savannah, GA 31411