Archive for the ‘marine chemistry’ Category

Microplastics article in Savannah Morning News

February 20, 2017
Students from Pierce County Middle School sort through the results of a trawl as part of an education program at the UGA Marine Education Center and Aquarium.

Students from Pierce County Middle School sort through the results of a trawl as part of an education program at the UGA Marine Education Center and Aquarium.

Reporter Mary Landers wrote a very nice article about Dr. Jay Brandes’s research into microplastic and microfiber pollution on the Georgia coast.

http://savannahnow.com/news/2017-02-19/skidaway-researchers-track-plastic-fibers-coastal-food-chain

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UGA Skidaway Institute research paper selected for Research Spotlight

February 3, 2017

 

Skidaway Institute's Aron Stubbins

Skidaway Institute’s Aron Stubbins

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.

A bank of permafrost thaws near the Kolyma River in Siberia

A bank of permafrost thaws near the Kolyma River in Siberia

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.

 

UGA Skidaway Institute associate professor cited for top research articles

December 2, 2016

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.

Skidaway Institute's Aron Stubbins

Skidaway Institute’s Aron Stubbins

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 scientists study role of sunlight on marine carbon dioxide production

July 21, 2016

Scientists at the University of Georgia Skidaway Institute of Oceanography have received a $527,000 grant from the National Science Foundation Chemical Oceanography Program to answer one of the long-standing questions about carbon in the ocean—the rate sunlight produces carbon dioxide from organic carbon molecules in the sea.

Jay Brandes, Leanne Powers and Aron Stubbins will use a new technique they developed to measure this process, which is known as photo-degradation.

Researchers Aron Stubbins (l) and Jay Brandes

Researchers Aron Stubbins (l) and Jay Brandes

The ocean is full of millions of different types of organic compounds. Some are consumed by bacteria, but many are not easily consumed and remain in the ocean for hundreds or thousands of years. However, near the surface, sunlight causes the breakdown of organic compounds and converts them into carbon dioxide through photo-degradation. Until recently, this process has been nearly impossible to measure directly in most of the ocean because the additional carbon dioxide produced per day is tiny compared to the existing high concentration of CO2 present in the sea.

Researcher Leanne Powers

Researcher Leanne Powers

Brandes described the problem as looking for a needle in a haystack.

“You might think this is not important because it is hard to measure, but that’s not true,” he said. “We’re talking about a process that takes place across the whole ocean. When you integrate that over such a vast area, it becomes a potentially very important process.”

The project became possible when the team developed a new technique to measure the change in CO2 concentration in a seawater sample. The concept was the brainchild of Powers, a Skidaway Institute post-doctoral research associate. The technique uses carbon 13, a rare, stable isotope of carbon that contains an extra neutron in its nucleus. Researchers will add a carbon 13 compound to a sample of seawater and then bombard the sample with light. The scientists will then use an instrument known as an isotope ratio mass spectrometer to measure the changes in CO2 concentration.

According to Brandes, this project will be breaking new ground in the field of chemical oceanography.

“We don’t know what the photo-degradation rates are in most of the ocean,” he said. “We are going to establish the first numbers for that.”

The team plans to take samples off the Georgia coast, as well as from Bermuda and Hawaii.

While they will continue to refine the carbon 13 technique, Brandes said it is now time to put that tool to work.

“It is now a matter of establishing what the numbers are in these different locations and trying to develop a global budget,” he said. “Just how much dissolved organic carbon is removed and converted to CO2 every year?”

The project is funded for three years. The team will also create an aquarium exhibit at the UGA Aquarium on the Skidaway Island campus to help student groups and the public understand river and ocean color.

VIDEO – The climate change issue you probably haven’t heard about

July 6, 2016

The soil in the Arctic holds a massive store of carbon. These remnants of plants and animals that lived tens of thousands of years ago have been locked in permafost, soil that is always frozen…until now.

UGA Skidaway Institute of Oceanography scientist Aron Stubbins is part of a team that travelled to Siberia to discover what happens to that carbon when the permafrost thaws.

 

Savannah newspaper article features UGA Skidaway Institute and R/V Savannah

July 5, 2016

The Savannah Morning News published a nice article over the weekend on the Rivers to Reefs teacher development program produced by Gray’s Reef National Marine Sanctuary. Although the Rivers to Reefs is not a Skidaway Institute program, the last day of the experience was on board the Research Vessel Savannah. The ship and Skidaway scientist Marc Frischer are prominently featured. Here is a link to the article and also to a slide show on the SMN Web site. Kudos to Dash Coleman for an excellent article and beautiful pictures.

http://savannahnow.com/education-news-news/2016-07-02/georgia-teachers-get-muddy-drenched-and-familiar-fish-trip-savannah

Photo Slide Show:

http://savannahnow.com/slideshow/2016-06-30/rivers-reefs-2016-expedition-grays-reef-national-marine-sanctuary#slide-1

UGA Skidaway Institute receives funding for regional glider network

July 1, 2016

University of Georgia Skidaway Institute of Oceanography researcher Catherine Edwards is leading a team that has received a five-year, $750,000 grant from the Southeast Coastal Ocean Observing Regional Association, or SECOORA, to establish a regional glider network.

Also known as autonomous underwater vehicles, the gliders are torpedo-shaped crafts that can be packed with sensors and sent on underwater missions to collect oceanographic data. 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.

UGA Skidaway Institute of Oceanography researcher Catherine Edwards assembles the tail cone assembly of a glider.

UGA Skidaway Institute of Oceanography researcher Catherine Edwards assembles the tail cone assembly of a glider.

The team will work collaboratively to operate regular glider missions on the continental shelf in an area from North Carolina to Florida known as the South Atlantic Bight. Regular coordinated experiments will involve simultaneous deployment of gliders at multiple locations off Florida, Georgia and North Carolina. Sensors on the gliders will allow the team to map temperature, salinity, density, dissolved oxygen and other scientific data over the entire South Atlantic Bight. The data will help scientists understand ocean processes and how the ocean physics may affect fisheries—for example, the location of fronts or areas of increased productivity where fish often congregate.

“This glider observatory is the first time regular glider efforts have been funded in the South Atlantic Bight and is complementary to larger SECOORA efforts in observing and modeling,” Edwards said. “The work is highly leveraged by contributions from each of the team members and partnerships with fisheries and observing groups at the National Oceanic and Atmospheric Administration and NASA.”

Edwards and her team have designed the deployments with input from fisheries management partners and interests of commercial and recreational fisheries. Gliders will also be outfitted with passive and active acoustics receivers that will record sound and measure signals from tagged fish.   Fisheries managers at Gray’s Reef National Marine Sanctuary, state Department of Natural Resources offices, the South Atlantic Fisheries Management Council and others will be able use this information to better understand the ocean “soundscape,” fish migrations and key species use of their habitat.

“The glider missions will contribute important information related to research underway at Gray’s Reef,” said Sarah Fangman, superintendent of Gray’s Reef National Marine Sanctuary. “We have been studying fish movement patterns inside the sanctuary, and the gliders’ acoustic receivers will provide a valuable new tool to expand where we can observe fish movements.”

In addition to regular coordinated experiments with multiple gliders and maximum regional coverage, the project will leverage opportunities to develop regular transects in areas where glider data may be of interest, for example near marine protected areas like Gray’s Reef National Marine Sanctuary and other critical habitat zones designated by the South Atlantic Fisheries Management Council.

The glider data will provide valuable information for validation of ocean models—regional models of ocean circulation funded by SECOORA as well as the larger modeling community. Further, the data will be packaged and used to improve ocean model forecasts.

“We’re sending all of the glider data to the National Glider Data Assembly Center as it comes in so that it can be assimilated into the U.S. Navy’s operational models,” Edwards said. “The gliders will improve Navy forecasts on the fly with real time data.”

The remainder of the research team includes Chad Lembke from the University of South Florida, Ruoying He from North Carolina State University, Harvey Seim from the University of North Carolina and Fumin Zhang from the Georgia Institute of Technology.

Data and maps from the project will be shared freely and made available to the research community, fisheries managers and other stakeholders and the general public in near-real time through SECOORA at http://secoora.org/ and the National Data Buoy Center.

UGA Skidaway Institute team studies nutrient levels in Georgia’s coastal estuaries

June 6, 2016

How much of a nutrient load is too much for Georgia’s coastal rivers and estuaries? A research team from University of Georgia Skidaway Institute of Oceanography is helping Georgia’s Environmental Protection Division answer that question. Their primary focus is on the estuary at the mouth of the Ogeechee River, where the researchers are measuring nutrient concentrations and other water properties to determine how they change as they flow through the estuary.

The nutrients are chemicals like nitrates and phosphates typically introduced into the rivers by agricultural runoff, storm water or sewage effluents, and the natural decay of organic matter in the river. When present in high concentrations, the nutrients act as fertilizer, promoting excessive growth of marine plants, especially microscopic marine plants called phytoplankton.

Researcher Kate Doyle lowers a sensor package into the water to measure salinity, temperature and depth.

Researcher Kate Doyle lowers a sensor package into the water to measure salinity, temperature and depth.

Elsewhere on the East Coast, excessive nutrients in estuaries have been linked to toxic algal blooms that can cause fish kills or shellfish closures. Death and decay of algal blooms by bacteria can drive oxygen concentrations down to levels that are unhealthy for other marine life. These are not presently known to be significant problems in Georgia’s waters, but scientists and regulators do not know what the thresholds are for developing water quality problems.

“The Georgia EPD wants to know how much nitrogen is coming down the river and whether it has any consequences when it gets to the estuary,” said UGA Skidaway Institute scientist William Savidge. “It doesn’t really matter if you have high nutrient concentrations if it is not having a harmful effect.”

The EPD is interested in these issues because they are mandated by the Environmental Protection Agency to set limits on nutrient levels for Georgia’s estuaries. Savidge describes the mandate as a difficult problem for several reasons.

“There is not any current and systematic information on nutrient conditions in most of the estuaries,” he said, “nor is there much information on the consequences of nutrient availability in the estuaries, and it’s those consequences that are the most important.”

They are currently mapping the biological and chemical properties of the Ogeechee River estuary each season to assess the nutrient changes throughout the year and to see what effects can be seen in the river and the estuary. Twice every quarter for the last year, the researchers have followed the incoming tide and sampled the river continuously as they moved upstream from the mouth of the estuary to fresh water. They used an onboard set of sensors to obtain continuous surface measurements of temperature, salinity, dissolved oxygen, chlorophyll (indicative of phytoplankton), turbidity and colored dissolved organic matter. In addition to the continuous surface measurements, the team stopped periodically and collected water samples from the bottom and throughout the water column. The product of each of these expeditions was a detailed map of conditions on the river, and when and where they are changing.

Researcher Lixin Zhu filters larger-volume surface water samples collected from the flow-through system to analyze for dissolved organic carbon.

Researcher Lixin Zhu filters larger-volume surface water samples collected from the flow-through system to analyze for dissolved organic carbon.

As they expected, Savidge and his team observed a wide range of conditions depending on the season. Nutrient inputs tend to be highest in the spring when agricultural fields are fertilized.

“Nutrient delivery is high in the spring, but we don’t have a high chlorophyll concentration in the Ogeechee River because, presumably, the nutrients are being washed off into the coastal ocean before any effect is noticed,” Savidge said

On the other hand, chlorophyll levels — which indicate phytoplankton population — are highest in the summer. Low summer river flow means water remains in the system longer. When combined with more sunlight and warmer temperatures, this slow flow this allows more time for the microscopic plants to grow.

In addition to sampling the Ogeechee River, the team is also conducting a smaller sampling project in the Altamaha River for comparison purposes.

Field work on the project will end in June, and Savidge expects to report the team’s findings to Georgia EPD by mid-summer.

“The Georgia EPD is going to have to balance the potential negative risks of nutrient loading versus the economic consequences of restricting nutrient additions,” Savidge said. “If, for example, most of the nutrient additions are agricultural, and that is creating problems downstream, the Georgia EPD may be forced by EPA to regulate nutrient additions, either by restricting how much fertilizer is placed on fields or mandating larger buffer zones around rivers and creeks.”

In addition to Savidge, the research team includes UGA Skidaway Institute scientists Jay Brandes and Aron Stubbins, research associate Kate Doyle and graduate student Lixin Zhu. UGA researchers Brock Woodson and Mandy Joye are also contributing.