After a run of nearly ten years, we are shutting down this blog site. We are moving our blogging activity to the new UGA Skidaway Institute website. Please visit us at http://www.skio.uga.edu/category/blog/
Two of our scientists, Drs. Dana Savidge and Catherine Edwards, are heavily involved in a project off of Cape Hatteras, NC. Funded by the National Science Foundation, the “Processes driving Exchange at Cape Hatteras” project also known as PEACH, is a collaborative research project focused on identifying the processes that control the exchange of waters between the shelves along the eastern seaboard of the US (Middle Atlantic Bight and Southern Atlantic Bight) and the open ocean.
One of their colleagues is blogging about the research. You can follow along here.
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.
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.
“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/
You can hear Dr. Elizabeth Harvey’s interview with Georgia Public Broadcasting here.
“You may have learned in school that photosynthesis is how plants use sunlight to turn water into hydrogen and carbon dioxide, its food, and oxygen, which it releases into the air for all of us to breathe. But photosynthesis doesn’t just happen on land – it happens in the ocean.
“Phytoplankton are tiny, single-celled algae basically, that live in the ocean,” explained Liz Harvey, Assistant Professor of Marine Science at University of Georgia’s Skidaway Institute of Oceanography, which is located on Skidaway Island. “They conduct photosynthesis just like land plants, trees and grass do, and they are prolific. They grow everywhere in the ocean.”
“There’s lots of different types of phytoplankton, they can do lots of different things,” Harvey continued. “But I think if you take one thing home, it’s that phytoplankton are important as they produce about fifty percent of the oxygen that you breathe. Land plants produce about half and then phytoplankton produce about half. These tiny little microscopic organisms are actually very, very important for helping to sustain life on earth. “
Producing half of earth’s supply of oxygen is only half of this organism’s job.
“Phytoplankton are eaten quite regularly and serve as food for other small organisms, which are then eaten by larger organisms which eventually lead up to fish, whales and sharks and all the really cool things that we think about when we think about the ocean,” Harvey said. “Although I would think phytoplankton are really cool too! So they serve a very important purpose to sustain the health and viability of fisheries. That’s another reason why we’re so concerned about what they’re doing, where they are, what types of phytoplankton are around – because they serve this purpose in supporting the larger fisheries as a whole.”
Reporter Mary Landers wrote a very nice article about Dr. Jay Brandes’s research into microplastic and microfiber pollution on the Georgia coast.
UGA Skidaway Institute external affairs manager was interviewed by Georgia Public Broadcasting about the institute and its work.
Doliolids are tiny marine animals rarely seen by humans outside a research setting, yet they are key players in the marine ecosystem, particularly in the ocean’s highly productive tropical and subtropical continental margins, such as Georgia’s continental shelf. University of Georgia Skidaway Institute of Oceanography scientist Marc Frischer is leading a team of researchers investigating doliolids’ role as a predator in the marine food web.
Doliolids are small, barrel-shaped gelatinous organisms that can grow as large as ten millimeters, or about four tenths of an inch. They are not always present in large numbers, but when they bloom they can restructure the marine food web, consuming virtually all the algae and much of the smaller zooplankton.
“The goal of this particular study is to find out what the doliolids are eating quantitatively,” Frischer said. “This is so we can understand where they fit in the food web.”
Scientists know from laboratory experiments what doliolids are capable of eating, but they don’t know what they actually do eat in the wild. They are capable of eating organisms as small as bacteria all the way up to much larger organisms.
“What they are eating and how much are they eating from the smorgasbord that is available to them, that is the question,” Frischer said. “We are investigating how much of those different prey types they are really eating out there across the seasons.”
The project involves intensive field work, including 54 days of ship time on board UGA Skidaway Institute’s Research Vessel Savannah. During the cruises they conduct trawls using special plankton nets to collect the doliolids. They also collect water samples to understand the conditions where the doliolids thrive.
“We take the doliolids and the water samples back to the laboratory, and that is where the magic begins,” Tina Walters, Frischer’s laboratory manager said.
Because the animals are gelatinous and very delicate, the researchers cannot use classical microscopic techniques to dissect the animals and analyze their gut content. Instead they extract DNA from the animals’ gut and use sequence-based information to determine what the doliolid ate.
“We go through a process called quantitative PCR,” Walters said. “So even though we can’t see the prey in a doliolid’s gut, because the prey have unique DNA sequences, we can identify and quantify them using a molecular approach.”
The three-year project is funded by a $725,000 grant from the National Science Foundation and will run until February 2018. Frischer’s collaborator on the project is Deidre Gibson from Hampton University. Gibson received her Ph.D. from the University of Georgia in 2000, and did much of her graduate research at Skidaway Institute with Professor Gustav Paffenhöfer. In addition to Walters, Savannah State University graduate student Lauren Lamboley is part of the team, along with a number of students at Hampton University. Several undergraduate research interns have also participated in the project, gaining hands-on research experience. Frischer is also working with the Institute for Interdisciplinary STEM Education at Georgia Southern University to engage K-12 teachers by inviting them to participate in the research cruises.
A research paper by University of Georgia Skidaway Institute of Oceanography scientist Aron Stubbins has been selected by the Journal of Geophysical Research-Biogeosciences to be featured as a Research Spotlight on the journal’s website and in the magazine Eos. Research Spotlights summarize the the best accepted articles for the Earth and space science community.
Stubbins’s paper, titled “Low photolability of yedoma permafrost dissolved organic carbon,” followed-up on earlier research into a massive store of carbon—relics of long-dead plants and other living things—preserved within ancient Arctic permafrost. That research showed the long-frozen permafrost is thawing, and the organic material it has preserved for tens of thousands of years is now entering the environment as dissolved organic matter in streams and rivers. Bacteria are converting the organic material into carbon dioxide, which is being released into the atmosphere.
The current paper examines the effect of sunlight on the dissolved carbon compounds. The researchers discovered that sunlight changes the chemistry of the permafrost carbon, however sunlight alone does not convert the permafrost carbon to carbon dioxide. The researchers concluded the decomposition of organic materials via bacteria is mostly likely the key process for converting permafrost carbon within rivers into carbon dioxide.
The research team includes co-lead author Robert Spencer of Florida State University; co-authors Leanne Powers and Thais Bittar from UGA Skidaway Institute; Paul Mann from Northumbria University; Thorsten Dittmar from Carl von Ossietzky University of Oldenburg; Cameron McIntyre from the Scottish Universities Environmental Research Centre; Timothy Eglinton from ETH Zurich; and Nikita Zimov from the Russian Academy of Science. While climatologists are carefully watching carbon dioxide levels in the atmosphere, another group of scientists is exploring a massive storehouse of carbon that has the potential to significantly affect the climate change picture.
In recent years, the public has become attuned to the problem of trash in the ocean, especially plastic, as images of the Great Pacific Garbage Patch have spread through media and the Internet. Now, University of Georgia Skidaway Institute of Oceanography professor Jay Brandes is leading a team investigating another issue closer to home on the Georgia coast: microplastics.
These are tiny pieces of plastic—smaller than five millimeters, or about a fifth of an inch—that have either been manufactured small or have broken down from larger pieces. They can be found in our beaches, water and in the digestive systems of aquatic wildlife.
“Five millimeters is still something you can see with the naked eye, but if you are out at the beach you aren’t going to pick up on it easily,” Brandes said. “So we say anything smaller than 5 millimeters is considered a microplastic.”
Funded by Georgia Sea Grant, Brandes and UGA Marine Extension and Georgia Sea Grant educator Dodie Sanders are in the first year of a two-year study to ascertain the extent of microplastic pollution in Georga’s coastal waters.
“Right now we are just trying to get an idea if there is a problem, and if there is, how prevalent it is,” Brandes said.
Microplastics come from several sources. Beginning in 1972, cosmetics manufacturers started adding plastic microbeads to exfoliating body washes and facial scrubs, which often pass freely through water treatment plants. When scientists reported finding these microbeads in rivers, lakes and oceans, it prompted a worldwide discussion on the issue. In 2015, Congress enacted legislation requiring the cosmetics industry to remove microbeads from rinse-off cosmetics by July of this year.
The sun also contributes to the production of microplastics. Plastic exposed to sunlight eventually fades, becomes brittle and breaks down into smaller pieces.
“All of us have probably seen a Styrofoam cup break down and the little beads come out,” Brandes said. “So there is the physical breakdown of the plastics into smaller and smaller pieces as they grind against each other and sand grains.”
To assess the extent of microplastic pollution on the Georgia coast, the research team makes use of the regular trawls conducted by UGA Marine Education and Aquarium staff. They collect the fish, shrimp, squid and other animals captured in the trawl and take them back to a laboratory where they will dissect them and analyze the contents of their gut.
“The first thing we have to do is to subject the gut contents to some extremely harsh chemicals to destroy the flesh and leave us mostly with the plastics,” Brandes said. “When dissecting even a small fish, it’s like looking for a needle in a haystack if you don’t get rid of all the other stuff.”
What is left is examined under a microscope and the plastic pieces identified and counted. The researchers have already found some surprises. Everywhere they look, whether it is beach sand or the contents of a fish’s stomach, they are seeing microfibers, extremely fine synthetic fiber used to create textiles.
According to Brandes, microfibers are pervasive—so much so that when the researchers take samples to the laboratory they have to take special measures to prevent contamination of their samples from microfibers floating in the air. It is not clear, however, if the microfibers are causing any harm to the marine organisms that ingest them.
“We are not finding fish with their stomachs packed with microfibers,” Brandes said. “It’s hard to tell if they are causing any real problems.”
The project also has an educational component. Brandes has taught workshops in which he takes groups of K-12 teachers to Tybee Island to collect sand and return it to the laboratory for microscopic analysis. He says the teachers are usually shocked with what they see.
“Hey, you thought that sand was clean, and from a tourist standpoint it is,” he said. “But there is still stuff in there and then you start talking about where it came from and what kinds of effects it may have.”
The project is expected to be completed and the results published by early 2018.