Tag Archives: research

Scientific serendipity: Researchers make surprising finding on ocean’s ‘thin layers’

Sometimes scientists start out researching one subject, but along the way, they come across something else even more interesting. This is what happened to University of Georgia Skidaway Institute of Oceanography researcher Adam Greer in the summer of 2016 when Greer was a post-doctoral associate at the University of Southern Mississippi. That fortuitous event resulted in a paper recently published in the journal Limnology and Oceanography with Greer as the lead author.

Adam Greer 1 650pGreer and his fellow researchers were on a cruise in the northern Gulf of Mexico to study the effects of river input on biological processes. They came across a natural phenomenon called a thin layer. These are oceanographic features found all over the world where biomass collects into a narrow portion of the water column–less than five meters thick vertically–and can extend for several kilometers horizontally. They tend to occur in stratified shelf systems.

“Surprisingly, there are few published studies on thin layers in the northern Gulf of Mexico, which is heavily influenced by rivers and highly stratified during the summer,” Greer said. “Thin layers are important because they are trophic hot spots, where life tends to congregate, and predators and prey interact.”

However, Greer said, thin layers are very difficult to analyze because they occur within a restricted portion of the water column, and most conventional ocean sampling equipment will not detect their influence on different organisms.

Greer and his colleagues were better equipped than most to study the thin layer. Rather than laying out a grid and taking a series of water samples, they were equipped with an In Situ Ichthyoplankton Imaging System (ISIIS). This imaging system was towed behind their research vessel and undulated through the water column, producing a live feed of plankton images and oceanographic data. By studying the video, they were able to map the distributions of many different types of organisms in great detail. The thin layer was composed of large chains of phytoplankton called diatoms and gelatinous zooplankton called doliolids.

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A crewman launches the ISIIS.

“Although we expected many different organisms to aggregate within the layer, this was not the case,” Greer said. “The only organisms that were concentrated within the layer were gelatinous organisms called doliolids. Other organisms that we expected to see, such as copepods, chaetognaths and shrimp, tended to congregate near the surface just south of the thin layer.”

The researchers determined that the area south of the thin layer was influenced by a surface convergence – two water masses colliding and pushing water downward at a slow rate. They believe that many organisms with active swimming ability, such as shrimps and copepods, could stay within the surface convergence, while more passive swimmers, such as doliolids would follow the trajectory of the thin layer and diatoms.

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An image from the In Situ Ichthyoplankton Imaging System passing through the thin layer. The long, slender filaments are chains of diatoms. The larger, oval plankton are doliolids

Greer and his colleagues discovered several other characteristics of the thin layer they had not anticipated. There was a higher concentration of live phytoplankton than expected. As a result, the thin layer also had a high concentration of dissolved oxygen due to the photosynthetic activity. The zooplankton were also aggregated into distinct microhabitats with different oceanographic properties — such as temperature, salinity and light. The microhabitats also contained different types and abundances of food.

“For a lot of these organisms, if you took the average abundance of food it wouldn’t be enough to survive,” Greer said. “So whatever mechanisms there are to create higher abundances of food, they are potentially really important for a number of different organisms.”

The other members of the research team were Adam Boyette, Valerie Cruz, Kemal Cambazoglu, Luciano Chiaverano and Jerry Wiggert, all from the University of Southern Mississippi; Brian Dzwonkowski and Steven Dykstra, from the University of South Alabama; and Christian Briseño‐Avena and Bob Cowen, from Oregon State University.
The paper can be viewed HERE.

Marine scientists map fish habitats

by Alan Flurry

Beyond the barrier islands of coastal Georgia, the continental shelf extends gradually eastward for almost 80 miles to the Gulf Stream. This broad, sandy shelf largely does not provide the firm foundation needed for the development of reef communities to support recreational and commercial fish species including grouper, snapper, black sea bass and amberjack.

“Natural and artificial reef habitats are important to Georgia fisheries because they provide hard, permanent structure on the Georgia shelf, which is dominantly a vast underwater desert of shifting sands,” said Clark Alexander, professor and director of the University of Georgia Skidaway Institute of Oceanography. “The Georgia Department of Natural Resources has invested significantly over the past several years in developing the capacity to map these areas to enhance the management of these reef communities.“

To increase the availability of high-quality hard bottom areas off Georgia, the DNR began an artificial reef-building program in 1971 to deploy materials at various locations across the continental shelf, from 2 to 30 miles offshore. Reef materials include concrete slabs and culverts from road, bridge and building demolition, subway cars, ships, barges, and U.S. Army tanks. Because some of these reefs are far offshore and DNR resources are limited, the status of some of that material has not been examined for decades.

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A bathymetric survey of Ossabaw Sound.

For the past five years, Alexander has been leading an effort to improve understanding of marine, coastal and estuarine habitats and functions using high-resolution sonar to map state water bottoms, with funding from the DNR Coastal Incentive Grant program. Alexander’s team has amassed critical depth and habitat information for five of Georgia’s sounds (Wassaw, Ossabaw, St. Catherine’s, Doboy and Sapelo), revealing deeply scoured areas where underwater cliffs have formed to create hard substrate where complex ecosystems and biological communities have developed.

“These inshore, hardbottom habitats should enhance biodiversity in the areas near these structures and enhance ecosystems supporting both commercial and recreational species across the continental shelf,” Alexander said.

Alexander is currently leading a new, three-year project mapping important fish habitats in state waters — the newly discovered estuarine habitats, and artificial reef structures within 10 nautical miles of shore – those areas most accessible to recreational anglers, boaters and divers. In addition, his research group is mapping previously unmapped portions of the sounds and tidal rivers deeper than 15 meters to discover the extent of these newly identified estuarine hardbottom habitats.

Skidaway Institute researchers will work with DNR to update the online “Boater’s Guide to Artificial Reefs” with accurate locations and imagery of deployed materials for these reefs. These new, more accurate artificial reef surveys will also document recent changes in the locations and integrity of placed materials and verify the low-tide water depths over all features in the artificial reefs to enhance navigational safety.

New high-tech microscope to bolster UGA Skidaway Institute’s microplastics research

A new, high-tech microscope is giving scientists at the University of Georgia Skidaway Institute of Oceanography a tool to study the tiniest particles and organisms in our environment in a whole new light. The Horiba Jobin Yvon XplorRA Plus Confocal Raman microscope uses lasers, rather than conventional light or a stream of electrons, to examine objects measuring smaller than a millionth of a meter or .04 thousandths of an inch.

“The way a Raman microscope works is fundamentally different from how conventional microscopes, such as those found in the classroom, operate,” UGA Skidaway Institute scientist Jay Brandes said. “With this instrument, a high energy laser beam is directed at the sample, and the instrument measures the light scattered back from it.”
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UGA Skidaway Institute researcher Jay Brandes with the Raman microscope.

What distinguishes it even more from traditional microscopes is a phenomenon called the Raman effect. This was discovered in the 1930s by Indian physicist Chandrasekhara Venkata Raman. With the Raman microscope, some of the scattered light comes from interactions with the molecules in the sample, and these interactions leave a spectral “fingerprint” that can be isolated from the laser light and measured. Those “fingerprints” can tell scientists what the material is made of, whether it is natural organics like bacteria or detritus, inorganic minerals or plastics.

“Because it uses a high tech, automated microscope to perform these measurements, maps of sample composition and even three-dimensional maps are possible,” Brandes said.

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The Raman microscope uses a laser to illuminate and analyze an object.

One immediate use for this instrument will be to study microplastic pollution in Georgia’s coastal environment. Brandes and a group of educators, students and volunteers, have been researching the microplastic pollution issue in coastal Georgia for several years. He says that locating and identifying microplastics in the environment or in an organism is difficult because of their tiny size.

“It’s not like it is a water bottle where you can look it and say ‘That’s plastic,’” Brandes said. “We see all kinds of microscopic particles, and, because they are so small and not always distinctively colored or shaped, it is difficult to distinguish microplastics from other substances.

“With this microscope, we will be able to look at a fiber and tell whether it is made of polyester, nylon, kevlar or whatever.”

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A microfiber as seen by the Raman microscope.

Brandes and his team have been looking at the microplastics problem from several angles. They have taken hundreds of water samples along the Georgia coast, filtered the samples and analyzed the captured particles and fibers. The researchers also examine marine organisms, like fish and oysters, to see what organisms are consuming the microplastics and to what extent.

The instrument will allow sub-micron analysis of complex samples from a wide variety of other projects. It will be available to UGA Skidaway Institute scientists as well as other scientists from throughout the Southeast. In addition to benefitting researchers, the Raman microscope will enhance educational programs conducted at Skidaway Institute and the through the UGA Department of Marine Sciences. Once a set of standard methods and protocols have been established, it will also be available to support scientific research from institutions and organizations from around the Southeast.

The instrument was purchased with a $207,000 grant from the National Science Foundation.

UGA Skidaway Institute scientists to study aerosol dust’s impact on life and chemistry in the ocean

A team of University of Georgia Skidaway Institute of Oceanography scientists has received a 4-year, $1 million grant from the National Science Foundation to study how dust in the atmosphere is deposited in the ocean and how that affects chemical and biological process there.

The research team of Clifton Buck, Daniel Ohnemus and Christopher Marsay will focus their efforts on a patch of the Pacific Ocean near Hawaii.

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Daniel Ohnemus (l) and Clifton Buck

“Our overall goal is to look at the aerosol loading and concentrations in the atmosphere, the rate that dust is deposited into the ocean and what happens to it once it is in the water column,” Buck said.

The chemistry of the ocean can be changed by the introduction and removal of elements, including trace elements which are present at low concentrations. In some cases, these elements are known to be vital to biological processes and ocean food webs. Near the shore, rivers are a large source for material from land to the ocean. Beyond the reach of rivers, and for most of the oceans, material blown from land through the air is the largest source of trace elements to surface waters.

“The ocean and the atmosphere are connected. What is in the atmosphere ends up in the ocean.” Ohnemus said. “Some part of what is in the ocean gets recycled back into the atmosphere, but mostly the movement is from the atmosphere to the ocean.”

The material enters the oceans dissolved in rain or by settling of dust particles. Understanding atmospheric sources of trace elements to the oceans is thus important to understanding both global chemical cycles and patterns of biological production. The team will look at trace metals like iron, which may appear in extremely low concentrations, but are essential to the growth of phytoplankton, the single-cell marine plants that serve as the base of the food web and produce approximately half the oxygen in the atmosphere. They will also look at other metals, like copper and cadmium, which are toxic and have a limiting influence on phytoplankton growth.

“Long-term atmospheric and ocean measurements are really hard to get at the same time in the same place, but that is what we are trying to do,” Ohnemus said.

Beginning in early 2021, the team will begin collecting aerosol samples at the Makai Research Pier on the southeast or windward side of Oahu. They will also undertake the first of six cruises to collect water samples at a spot in the Pacific known as the Hawaii Ocean Time-Series Station Aloha. This is a six-mile wide section of ocean approximately 200 kilometers from Oahu where oceanographers from around the world study ocean conditions over long time spans.

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This chart shows the location of the research field sites. Credit: Lee Ann DeLeo

A key goal of this project will be to obtain relatively frequent measurements over two full annual cycles. By taking weekly aerosol samples and water samples every few months, the researchers hope to be able to obtain a picture of how the atmosphere and the ocean change on a weekly, monthly or seasonal basis.

“It is important to point out that the dust transport over the North Pacific has a distinct seasonal cycle,” Buck said. “Dust concentrations are going to be different during the winter than they are in the summer.”

In the past there have been studies of aerosol dust concentrations in that region, but they were conducted at the top of the Mauna Loa volcano.

“That’s almost 12 thousand feet up, and not necessarily representative of what is being deposited in the ocean,” Buck said. “That is the leap we are trying to make here.”

The researchers chose Hawaii as the site for their field work for several reasons. Hawaii offers direct access to the remote, nutrient-limited open ocean. Hawaii also has strong seasonal fluctuations to its aerosol inputs, meaning there should be measurable changes over the two-year time series. The Hawaii Ocean Time Series has conducted regular research cruises to Station ALOHA since the mid-1980s, so there is already a historic collection of relevant data. From a practical standpoint, it also means the scientists will have regular access to those cruises to collect their ocean samples.

Although this project will not focus on marine plants, those plants are the reason the scientists want to answer questions about the marine chemistry.

“A very small amount of aerosol dust from a desert in China can provide enough nutrients to satisfy plant growth for weeks,” Ohnemus said. “So it can have a huge influence on which algae will grow where and how successful they are.”

Working with contractors from Florida International University, the research team will use a radioisotope of beryllium to measure the rate of atmospheric deposition. Beryllium-7 is created only in the upper atmosphere by the exposure of nitrogen and oxygen to cosmic rays, and has a half-life of 53 days. By measuring the concentration of beryllium-7 in samples, they will be able to estimate the deposition rate at which beryllium and other materials are being deposited on the surface.

The team will also contract with scientists at the University of Hawaii to collect aerosol samples on a more frequent basis than the Georgia-based researchers would be able to do themselves.

The project is funded by NSF Grant #1949660 totaling $1,074,114.

Despite COVID-19 delays, UGA Skidaway Institute scientist heading home from the Arctic

After four months at sea, including two and a half months on board a German ice breaker locked in the Arctic ice cap, University of Georgia Skidaway Institute of Oceanography scientist Chris Marsay is on his way home. His return trip comes six weeks later than planned due to travel restrictions imposed by the COVID-19 crisis.

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Chris Marsay, all wrapped up for working out on the ice during windy conditions.

Marsay has been on board the research vessel Polarstern as part of a major international research project to study climate change in the Arctic named Multidisciplinary drifting Observatory for the Study of Arctic Climate, or “MOSAiC.” Last fall the Polarstern sailed into the Arctic Ocean until it became locked in the ice. The plan was for the ship to drift with the ice for a year all the while serving as a headquarters for scientists to study Arctic climate change. Scientists were scheduled in shifts or “legs” to work for two to three months at a time. However, unable to exchange the science teams by either air or with another ice breaker, MOSAiC organizers decided to pull the Polarstern out of the ice pack and leave the research station for an estimated three weeks while the changeover takes place.

“My time working at the MOSAiC ice floe has come to an end, and I am currently traveling south on the Polarstern towards Svalbard where the exchange between personnel from legs three and four of the project will take place,” Marsay said. “Due to the travel restrictions in place because of COVID-19, it was not possible to carry out the exchange at the ice floe itself as originally planned.”

The replacement team is already at Svalbard aboard two other German vessels. They completed a two-week quarantine and multiple coronavirus tests before departure. The teams will exchange ship-to-ship in a fiord since Svalbard, a Norwegian archipelago, is closed to outside visitors because of COVID-19.

According to Marsay, his time at the MOSAiC ice floe has been eventful. “The ice was much more dynamic than it had been during the first months of the MOSAiC project,” he said. “Cracks and leads frequently opened up in the area around the ship, and the ice movement also formed ridges of ice blocks several feet high.”

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A crack that opened up next to the ship in mid-March meant that some equipment had to be hurriedly moved to safety.

All of these events restricted access to some research sites, but the work continued, providing new sampling opportunities for the researchers.

This was not Marsay’s first trip to the Arctic. A 2015 research cruise took him to the North Pole, but this trip was a new experience. “It’s been unique to witness the transition from winter to spring in the central Arctic Ocean,” he said. “During our time at the floe we experienced a minimum temperature of negative 40 degrees Celsius, not accounting for wind chill, and a maximum of zero degrees Celsius. The sun did not rise until two weeks after we arrived at the floe, and has not set since late March.”

Marsay also experienced windy days with storm-force winds and whiteout conditions due to blowing snow, and days with beautiful clear skies when the sun reflecting off the snow was dazzling, he said.

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As calm conditions gradually return after a couple of days of windy conditions, Polarstern is visible through some blowing snow at ground level.

During his participation in MOSAiC, Marsay collected snow, ice cores, sea water and aerosol samples as part of our project studying the atmospheric deposition of trace elements in the central Arctic.

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Each Monday, Marsay was part of a team that collected multiple ice cores at a site far enough away from the ship that a Ski-Doo and sledges were needed.

He also learned some new skills, including driving a Ski-Doo, and on several occasions he carried a rifle and served as a polar bear guard for colleagues.

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The researches had one polar bear visit (that they know of) during leg 3. These footprints within a couple of hundred yards of Polarstern.

“We on board will have been at sea for over four months by the time we get to Germany,” Marsay said. “When we started, the COVID 19 virus was not widespread outside of China.

“We have all been following the news from back home, and although we’re looking forward to getting home, everyone is expecting some initial difficulties getting used to the way that public life has changed while we’ve been away.”

UGA Skidaway Institute, SECOORA christen new glider

Researchers from the UGA Skidaway Institute of Oceanography and the Southeast Coastal Ocean Observing Regional Association (SECOORA) welcomed a new glider to their research fleet with a christening ceremony at UGA Skidaway Institute on Tuesday, April 23. The new glider was purchased and is owned by SECOORA, but will be based at UGA Skidaway Institute and operated by the UGA Skidaway Institute glider team headed by Catherine Edwards.

Gliders are torpedo-shaped crafts that can be packed with sensors and sent on underwater missions to collect oceanographic data, and are classified as autonomous underwater vehicles, meaning that they operate untethered on their own. Equipped with satellite phones, the gliders surface periodically to transmit their recorded data and to receive new instructions during missions that can last from weeks to months.

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The glider is named Franklin, after Benjamin Franklin, who ordered the first chart of the Gulf Stream.

The christening ceremony, based on traditional versions for naming and renaming boats, called upon the favor of the gods of the sea, the wind, the tide and the Gulf Stream, and was offered by Edwards, research professional Ben Hefner, SECOORA executive director Debra Hernandez and UGA Skidaway Institute assistant director Marc Mascolo.

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Catherine Edwards raises a glass to Franklin.

Hernandez then capped the ceremony by smashing a bottle of champagne against a metal weight positioned near Franklin’s nose.

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Debra Hernandez completes the ceremony.

Franklin is outfitted with a pumped conductivity-temperature-depth sensor and a three-channel fluorometer that measures chlorophyll, dissolved organic matter and turbidity. It also has a dissolved oxygen sensor and two built-in Vemco acoustic receivers that listen for tagged fish and other animals. The glider is powered by lithium-ion batteries that will allow it to remain on mission for up to five to six weeks at a time without recharging.

Franklin’s first deployment was a SECOORA mission at Gray’s Reef National Marine Sanctuary. It was joined on the mission by UGA Skidaway Institute’s other glider, named Angus.

UGA Skidaway Institute gliders improve hurricane predictions

The models hurricane forecasters use to predict the paths of storms have become much more accurate in recent years, but not so much the models’ ability to accurately predict a storm’s intensity. Now, underwater gliders, operated by researchers at the University of Georgia Skidaway Institute of Oceanography, are part of a national effort to use marine robots to improve the accuracy of storm forecast models.

UGA Skidaway Institute research technician Ben Hefner launches a glider into the ocean. Photo courtesy MADLAWMEDIA

Two storms from the 2018 hurricane season provide examples of how quickly storm intensity can change. Hurricane Florence was predicted to be a Category 5 storm, but she weakened significantly before making landfall in North Carolina as a Category 1 storm on September 14. On the other hand, a month later, Hurricane Michael grew from a Category 1 to a Category 5 storm in just two days and hit the Florida panhandle on October 10.

Hurricanes feed off of heat from warm ocean waters like that found in the Caribbean, and in the Gulf Stream and shallow waters off the southeast United States, known as the South Atlantic Bight. This can be a tremendous source of energy for developing storms. Heat is transferred between the ocean and atmosphere at the ocean’s surface, but it is important to understand the amount of subsurface heat as well.

“Places where warm waters near the surface lie over cooler water near bottom, winds and other factors can mix up the water, cooling the surface and limiting the heat available to the atmosphere,” UGA Skidaway Institute researcher Catherine Edwards said. “Satellite data provides a nice picture of where the surface ocean is warm, but the subsurface temperature field remains hidden.”

UGA Skidaway Institute researcher Catherine Edwards examines the tail assembly of a glider.

This is where autonomous underwater vehicles, also known as gliders, can collect valuable information. Gliders are torpedo-shaped crafts that can be packed with sensors and sent on underwater missions to collect oceanographic data. The gliders measure temperature and salinity, among other parameters, as they profile up and down in the water. Equipped with satellite phones, the gliders surface periodically to transmit their recorded data during missions that can last from weeks to months.

“This regular communication with the surface allows us to adapt the mission on the fly, and also process and share the data only minutes to hours after it has been measured,” Edwards said. “By using a network of data contributed by glider operators around the world, the U. S. Navy and other ocean modelers can incorporate these data into their predictions, injecting subsurface heat content information into the hurricane models from below.”

The 2018 hurricane season provided Edwards and her colleagues a fortuitous opportunity to demonstrate the value of glider data. Edwards deployed two gliders in advance of Hurricane Florence. One was launched off the North Carolina coast and the other further south, near the South Carolina-Georgia state line. The gliders discovered the models’ ocean temperature forecasts were significantly off target. Edwards points to charts comparing the predictions from ocean models run in the U.S. and Europe with the actual temperatures two days before Florence made landfall.

On the south side of the storm path, the models predicted that the ocean had a warm, slightly fresh layer overtopping cooler, saltier water below, but the glider revealed that the water column was well-mixed and, overall, warmer and fresher than predicted. On the north side of the storm, the models predicted warm, well-mixed water, but the glider detected a sharp temperature change below the surface, with a much cooler layer near-bottom. However, the most surprising part was just how stratified the water was.

“There is almost a 14-degree Celsius (approximately 25 degrees Fahrenheit) error that the glider corrects in the model,” she said. “The model and data agree near-surface, but the models that don’t use the glider data all miss the colder, saltier layer below. The model that incorporated glider data that day is the only one that captures that vertical pattern.”

Not only can gliders provide a unique view of the ocean, they fly on their own, reporting data regularly, before, during and after a hurricane, making them a powerful tool for understanding the effects of storms.

“The glider data is being used in real time,” Edwards said. “These real time observations can improve our hurricane forecasts right now, not just in a paper to be published a year from now.”

Edwards and collaborator Chad Lembke, at the University of South Florida, had a third glider deployed in August before Florence as part of a glider observatory she runs for the Southeast Coastal Ocean Observing Regional Association (SECOORA). While it was recovered about a little over a week before Florence made landfall, the glider helped define the edge of the Gulf Stream, which is an essential ocean feature that is very hard for models to get right.

“So it’s possible that the data from that glider already improved any tropical storm predictions that use ocean models and take that glider data into account, because the Gulf Stream is so important in our region,” Edwards said.

Edwards works with colleagues from other institutions through SECOORA. Together they are making plans for the 2019 hurricane season. Funded by a $220,000 grant from the National Oceanic and Atmospheric Administration, they plan to pre-position a number of gliders in strategic locations to be ready for deployment in advance of incoming storms.

“Gliders are like the weather balloons of the ocean,” Edwards said. “Imagine how powerful a regular network of these kinds of glider observations could be for understanding the ocean and weather, and how they interact.”

UGA Skidaway Institute scientists publish two papers on Arctic processes

The Arctic is experiencing the effects of climate change faster than anywhere on the planet, yet it is one of the least understood regions, due largely to the difficulty of making observations and collecting samples there. With the support of National Science Foundation funding, two University of Georgia Skidaway Institute of Oceanography scientists are studying the biogeochemical processes in the Arctic and recently had their research published in two peer-reviewed science journals.

Postdoctoral researcher Christopher Marsay and assistant professor Clifton Buck have been participants in the international GEOTRACES program which aims to improve the understanding of biogeochemical cycles in the ocean, focusing on important trace elements. Trace elements are present in the ocean in very low concentrations, however some of those elements are essential for marine life and can influence the functioning of ocean ecosystems while others are potentially toxic to plants and animals.

Cliff Buck works with deck equipment during a GEOTRACES cruise in the Pacific Ocean.

“The Arctic part of the GEOTRACES program is particularly important because the region is already showing significant changes as a result of climate change and is relatively poorly studied with respect to many trace elements,” Marsay said.

Marsay is the lead author on both papers, which are the result of analysis of samples he collected on a 64-day GEOTRACES cruise from Dutch Harbor, Alaska to the North Pole and back from August through October 2015.

“On this cruise, our research goals were to describe the chemistry of atmospheric deposition to the region,” Buck said. “These data will then be shared with the scientific community to help better understand biogeochemical cycling of trace elements in the Arctic Ocean.”

The first paper, published in the journal Chemical Geology, describes the concentrations of 11 trace elements in atmospheric samples that Marsay collected during the cruise by pumping large volumes of air through filters. The sources of this material could include natural material from land surfaces, smoke and soot from burning vegetation, and emissions from industrial activity.

“We compare the results to other ocean regions and speculate as to the sources of the material reaching the Arctic,” Marsay said. “An important part of the work is that we used the concentration data to estimate how much of these chemicals settle from the atmosphere to the surface of the ocean.”

In addition to Marsay and Buck, co-authors included David Kadko from Florida International University, William Landing and Brent Summers from Florida State University, and Peter Morton from the National High Magnetic Field Laboratory.

The second paper was published in the journal Marine Chemistry. In it, Marsay and his co-authors examine trace elements in Arctic melt ponds. Melt ponds are a widespread feature of the sea ice in the Arctic during the summer months. As snow melts it forms ponds on top of the ice which eventually drain into the surface ocean.

Chris Marsay collecting samples at the North Pole.

“Melt ponds are an important intermediate step in atmospheric deposition to the surface ocean that is unique to the polar regions and not very well studied,” Marsay said. “Ongoing climate change in the Arctic will change this pathway, and we want to know how that may affect distribution and biological availability of trace elements in the surface ocean.”

The paper brought together measurements of several trace elements made by different research groups involved in the GEOTRACES project. It showed that the chemistry in melt ponds is also influenced by material in sea ice and the seawater beneath the ice, which modifies the chemistry of material deposited from the atmosphere before it reaches the surface ocean.

Additional co-authors on the paper included Ana Aguilar-Islas from the University of Alaska Fairbanks, Jessica Fitzsimmons, Laramie Jensen and Nathan Lanning from Texas A&M University, Mariko Hatta from University of Hawai’i at Manoa, Seth John and Ruifeng Zhang from the University of Southern California, David Kadko from Florida International University, William Landing from Florida State University, Peter Morton from the National High Magnetic Field Laboratory, Angelica Pasqualini from Columbia University, Sara Rauschenberg and Benjamin Twining from the Bigelow Laboratory for Ocean Sciences, Robert Sherrell from Rutgers University, and Alan Shiller and Laura Whitmore from the University of Southern Mississippi.

The two papers can be accessed through the UGA Skidaway Institute website at: https://www.skio.uga.edu/research/research-publications/.

Ohnemus joins UGA Skidaway Institute faculty

Chemical oceanographer Daniel Ohnemus has joined the faculty of UGA Skidaway Institute of Oceanography and the UGA Department of Marine Sciences as an assistant professor.

Ohnemus received his bachelor’s degree from Williams College and his Ph.D. in chemical oceanography from the Massachusetts Institute of Technology and Woods Hole Oceanographic Institution Joint Program. He joined UGA Skidaway Institute following a postdoctoral appointment at Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine.

Ohnemus’ research focuses on marine particles—the mixture of living organisms and non-living chemicals that transport and transform material within the oceans.

“All living organisms need small ‘trace’ amounts of elements like iron and copper to live,” Ohnemus said. “Unlike on land where plants can get these elements from soil, algae in the oceans have to get them from much rarer things like dust, other cells or seawater itself. The limited availability of these elements is an important control on many marine ecosystems.”

The son of a lobsterman and an elementary school educator, Ohnemus grew up on Cape Cod and became fascinated with the ocean at a young age. In fourth grade, his class visited Woods Hole to take part in a satellite video call with marine scientists off the Galapagos Islands. Seeing underwater robots explore a coral reef got Ohnemus hooked on marine science.

At Williams College, he pursued a double major in biology and chemistry. After graduation, he returned to Woods Hole, first as a research technician and later as a graduate student. After earning his Ph.D., he completed a postdoctoral appointment at the Bigelow Laboratory for Ocean Sciences, continuing to concentrate on marine particles and trace elements.

Glider partners come to the rescue during Hurricane Irma

Hurricane Irma presented an interesting problem to UGA Skidaway Institute scientist Catherine Edwards and other glider operators in the Southeast. They had several autonomous underwater vehicles or “gliders” deployed off the east coast as the hurricane approached, including Skidaway Institute’s glider, “Modena.” Edwards and the others were confident the gliders themselves would be safe in the water, but the computer servers that control them would not.

Catherine Edwards works on “Modena.”

The gliders are equipped with satellite phones. Periodically, they call their home server, download data and receive instructions for their next operation. It was expected that Skidaway Institute would lose power for at least several days (as did happen). However, Skidaway’s backup server partner at the University of South Florida’s marine science facility in St. Petersburg, Fla. was also directly in the storm’s projected path.

“In the week before she hit, Irma sort of blew up our hurricane emergency plans,” Edwards said.

Several other options, including Teledyne Webb’s back-up servers and Rutgers University were not feasible for technical reasons. Glider operators at Texas A&M University came to the rescue. Catherine was able to instruct “Modena” to switch its calls over the Texas A&M server. No data was lost and “Modena” continued its mission.

According to Edwards, two big lessons emerged from the experience.

“First, most of us rely on nearby or regional partners for emergency and backup support, but disasters are regional by nature, and the same Nor’easter or hurricane can take you down along with your backup,” she said. “Second, there aren’t a lot of glider centers that can absorb several gliders on a day’s notice, and there are some compatibility and operations issues involved, so it is best to identify our potential partners and build out these steps into our emergency plans well in advance.”