Posts Tagged ‘woods hole’

UGA Skidaway Institute scientists study microbial chemical warfare

April 18, 2017

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.”

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.

A microscopic view of a population of 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.

NOTE:  A complementary video with an interview with Dr. Harvey is available at http://www.skio.uga.edu/news/videos/

 

Advertisements

Skidaway Institute’s Elizabeth Harvey embarks on month-long Atlantic cruise

October 27, 2015

UGA Skidaway Institute scientist Elizabeth Harvey will be spending the next month on board Woods Hole’s Research Vessel Atlantis.NAAMESbannerWithSat w

The North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) is a five year investigation to resolve key processes controlling ocean system function, their influences on atmospheric aerosols and clouds and their implications for climate.

Here is Dr. Harvey’s first post on the cruise’s blog. 

Elizabeth Harvey joins Skidaway Institute faculty

September 3, 2015

OLYMPUS DIGITAL CAMERABiological oceanographer Elizabeth Harvey has joined the faculty of the University of Georgia Skidaway Institute of Oceanography as an assistant professor.

Harvey received her bachelor’s degree in marine science from the University of Maine and a master’s in environmental science from Western Washington University. She earned her doctorate in oceanography from the University of Rhode Island. Immediately prior to joining Skidaway Institute, she completed a post-doctoral fellowship at Woods Hole Oceanographic Institution.

Harvey’s research focus is on the mechanisms of mortality in the planktonic environment in the ocean and how that influences food web structure and biogeochemical cycling.

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.

Fresh fish and dirty laundry

November 19, 2013

Skidawawy Institute Clifton Buck continues is account of his lengthy cruise across the South Pacific from Ecuador to Tahiti.

Ahoy There!

Current Position: S 15.75’ W 105.08’

It’s another Sunday at sea and we are transiting between Stations 15 and 16. Many in the science party use these 10-12 hour lulls in the action to catch up on sleep, update data logs, or continue their daily slog through the seemingly endless volume of samples. But for me, Sunday is laundry day (not all that different from at home in Savannah). Our ship has a laundry room, though no laundry service, and each compartment of cabins is assigned a particular day of the week for tending to dirty linens. The laundry is located deep within the bowels of the ship along with the food stores. Land lubbers may go queasy at the thought of folding their skivvies beneath the waterline but I find the sound of the waves breaking against the hull to be soothing to hear while I search for that missing sock.

Earlier today, we were treated to a lunch of freshly caught Mahi.

Ship’s oiler Orlando cleaning our catch.

Ship’s oiler Orlando cleaning our catch.

   Our usual operations do not allow for fishing but there are times the ship steams slowly enough to allow for trolling. Several members of the crew are avid anglers and are quick to deploy hand lines from the stern. It is a great treat for us when a fish is landed and one can imagine the joy preindustrial mariners must have felt at the prospect of fresh fish.

The internet has been filled with erroneous reports concerning the ongoing leak of radionuclides from the earthquake damaged Fukushima power plant. These reports suggest that contaminated waters and debris are spreading across the Pacific Ocean posing a threat to human health in the Americas. We are all exposed to naturally occurring radiation throughout our daily lives and seawater is chock full of naturally occurring radionuclides. While the area immediately surrounding the plant is grossly contaminated and radionuclides continue to seep from the site, there is no risk to us or anyone in North or South America. The radionuclides released in Japan are quickly diluted in the Pacific Ocean and are constantly disappearing due to radioactive decay. The Fukushima disaster has caused in an increase in radioactivity of about 25% above this natural background level in the near shore (~40km). At 600km from shore, the increase is only 2% above natural levels. In fact, there are several scientists from the Woods Hole Oceanographic Institution (WHOI) on board who were on the scene in Japan shortly after the earthquake struck. The risk of radiation exposure at their study site, just a few miles from the plant, was so low that no personal protective equipment was required whatsoever. Please visit WHOI’s Café Thorium website  for more information. So you can dig in to all of the sustainably caught seafood you like without fear of glowing in the dark!

Exit Challenge: Try to identify the seabirds in these photos. Post your answers in the comments.

Can you identify this seabird?

Can you identify this seabird?

What kind of bird am I?

What kind of bird am I?

Fossil fuels fire glacier carbon cycle according to Skidaway Institute scientist

February 20, 2012

New clues as to how the Earth’s remote ecosystems have been influenced by the industrial revolution are locked, frozen in the ice of glaciers. That is the finding of a group of scientists, including Aron Stubbins of the Skidaway Institute of Oceanography.

The research is published in the March 2012 issue of Nature Geoscience.

The key to the process is carbon-containing dissolved organic matter (DOM) in the glacial ice. Glaciers provide a great deal of carbon to downstream ecosystems. Many scientists believe the source of this carbon is the ancient forests and peatlands overrun by the glaciers. However, Stubbins and his colleagues believe the carbon comes mainly from contemporary biomass and fossil fuel burning that gets deposited on the glacier surfaces. Once deposited on the glacier surface by snow and rain, the DOM moves with the glacier and is eventually delivered downstream where it provides food for microorganisms at the base of the marine food web.

Aron Stubbins

“In vibrant ecosystems like in the temperate or tropical zones, once this atmospheric organic material makes landfall it is quickly consumed by the plants, animals and microbial populations,” said Stubbins. “However in frigid glacier environments, these carbon signals are preserved and standout.”

“Remote regions are often perceived as being pristine and devoid of human influence”, Stubbins continued. “Glaciers show us that nowhere goes untouched by industry. Instead, burning fuels has an impact upon the natural functioning of ecosystems far removed from industrial activity.”

Glaciers and ice sheets together represent the second largest reservoir of water on earth, and glacier ecosystems cover ten percent of the Earth, yet the carbon dynamics underpinning those ecosystems remain poorly understood.

“Increased understanding of glacier biogeochemistry is a priority, as glacier environments are among the most sensitive to climate warming and the effects of industrial emissions” said Stubbins.

Globally, glacier ice loss is accelerating, driven in part by the deposition of carbon in the form of soot or “black carbon”, which darkens glacier surfaces and increases their absorption of light and heat. Biomass and fossil fuel burning by people around the globe are the major sources of that black carbon.

Stubbins and his fellow scientists have conducted much of their research at the Mendenhall Glacier near Juneau, Alaska. Mendenhall and other glaciers that end their journey in the Gulf of Alaska receive a high rate of precipitation. High levels of rain and snow acts to strip the atmosphere clean of organics, dumping it on the glacier. Consequently, these glaciers are among the most sensitive to global emissions of soot.

The researchers’ findings also reveal how the ocean may have changed over past centuries. The microbes that form the very bottom of the food web are particularly sensitive to changes in the quantity and quality of the carbon entering the marine system. Since the study found that the organic matter in glacier outflows stems largely from human activities, it means that the supply of glacier carbon to the coastal waters of the Gulf of Alaska is a modern, post-industrial phenomenon. “When we look at the marine food webs today, we may be seeing a picture that is significantly different from what existed before the late-18th century,” said Stubbins. “It is unknown how this manmade carbon has influenced the coastal food webs of Alaska and the fisheries they support.”

A warming climate will increase the outflow of the glaciers and the accompanying input of dissolved organic material into the coastal ocean. This will be most keenly felt in glacially dominated coastal regions, such as those off of the Gulf of Alaska, Greenland and Patagonia. These are the areas that are experiencing the highest levels of glacier ice loss.

“Although it is not known to what extent organic material deposition has changed and will continue to alter glacially-dominated coastal ecosystems or the open ocean, it is clear that glaciers will continue to provide a valuable and unique window into the role that the deposition of organic material plays in our changing environment,” Stubbins said.

Stubbins collaborators on the project included Eran Hood and Andrew Vermilyea from the University of Alaska Southeast; Peter Raymond and David Butman from Yale University; George Aiken, Robert Striegl and Paul Schuster from the U.S. Geological Survey; Patrick Hatcher, Rachel Sleighter  and Hussain Abdulla from Old Dominion University; Peter Hernes from the University of California-Davis; Durelle Scott from Virginia Polytechnic Institute and State University; and Robert Spencer from Woods Hole Research Center.

The paper can be viewed on-line at http://dx.doi.org/10.1038/NGEO1403

Further details are available at http://www.skio.usg.edu/?p=research/chem/biogeochem/glaciers. This work is being continued with support from the National Science Foundation: http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1146161

The Skidaway Institute of Oceanography is an autonomous research unit of the University System of Georgia located on Skidaway Island in Savannah, Ga. The mission of the Institute is to provide the State of Georgia with a nationally and internationally recognized center of excellence in marine science through research and education.

Skidaway Institute scientist studies hydrothermal vents, undersea volcano

August 22, 2011

Skidaway Institute of Oceanography scientist Aron Stubbins joined a research cruise this summer to study hydrothermal vents, but what his fellow scientists found was a recently erupted undersea volcano.

Aron Stubbins

The Axial Seamount is an undersea volcano located about 250 miles off the Oregon coast and is one of the most active and intensely studied seamounts in the world. What makes the event so intriguing is that Bill Chadwick, an Oregon State University geologist, and Scott Nooner, of Columbia University, had forecast the eruption five years before it happened. Their forecast, published in the Journal of Volcanology and Geothermal Research, was based on a series of seafloor pressure measurements that indicated the volcano was inflating and is the first successful forecast of an undersea volcano.

The discovery of the new eruption came on July 28, when Chadwick, Nooner and their colleagues led an expedition to Axial aboard the R/V Atlantis, operated by the Woods Hole Oceanographic Institution. Using “Jason,” a remotely operated robotic vehicle (ROV), they discovered a new lava flow on the seafloor that was not present a year ago. The expedition was funded by the National Science Foundation and the National Oceanic and Atmospheric Administration (NOAA).

“When eruptions like this occur, a huge amount of heat comes out of the seafloor, the chemistry of seafloor hot springs is changed, and pre-existing vent biological communities are destroyed and new ones form,” Chadwick said. “Some species are only found right after eruptions, so it is a unique opportunity to study them.”

Stubbins was on the cruise to study the dissolved organic matter being released from the hydrothermal vents in the ocean floor with Pamela Rossel from the Max Planck Institute Marine Geochemistry group in Oldenburg, Germany, and David Butterfield from the NOAA Vents program. Funding for Stubbins and Rossel was provided by the Hanse-Wissenschaftskolleg (www.h-w-k.de) and Max Planck Institute, both in Germany.

“The material from the vents reaches over 300 degrees centigrade,” Stubbins said.

At that temperature, the heat modifies the dissolved organic matter, altering its chemistry and reactivity, and therefore, its fate in the water column.

“These ecosystems are amazing,” Stubbins continued. “They include large worms, snails, fish and shrimp that live thousands of meters below the ocean. All this life is fueled, not by the sun, but by chemicals released from the vents”

The manipulator arm of the ROV Jason prepares to sample the new lava flow that erupted in April 2011 at Axial Seamount, located off the Oregon coast. (photo courtesy of Bill Chadwick, Oregon State University; copyright Woods Hole Oceanographic Institution)

Immediately after an eruption the whole system is in flux, continued Stubbins. Vents in the ocean floor called snow blower vents produce streams of white particles, creating a snow globe effect. These snow blowers are only short lived.

“Getting samples from these ephemeral systems provided us with a novel opportunity to gain new insight into these deep sea ecosystems” said Stubbins.

For Chadwick and Nooner the eruption was vindication for years of hard work. “The acid test in science – whether or not you understand a process in nature – is to try to predict what will happen based on your observations,” Chadwick said. “We have done this and it is extremely satisfying”

For Stubbins and Rossel, the journey of discovery is just beginning. “Nobody knows how much carbon is pumped into the ocean by these snow blowers or the other vents associated with the eruption” Stubbins said. The good fortune of sampling right after a major eruption has provided a unique opportunity to find out.