Sebastian Barkett awarded a GSA Graduate Student Research Grant

Congratulations to Sebastian Barkett who was recently awarded the GSA Graduate Student Research Grant! Funds will support his work on ancient wildfires at the Paleocene-Eocene Thermal Maximum (PETM), which occurred ~56 million years ago and climatic changes are analogous to what is happening today. Sebastian also received a travel grant from GSA to present his findings on microfossil charcoal and molecular marker proxies for paleowildfire at the GSA Connects 2024 Meeting in Anaheim, CA later this month.

Charcoal grains identified at the PETM along the paleo-continental shelf in present day Maryland. Photos by Sebastian Barkett.

The primary role of the GSA research grants program is to provide partial support of master's and doctoral thesis research in the geological sciences for graduate students enrolled in universities in the United States, Canada, Mexico and Central America.

New paper shows dissolved black carbon measurements could be affected by "free BPCAs" in fire-affected waterways

Benzenepolycarboxylic acids (BPCAs), the molecular structures shown here, are formed during fire and their inherent presence in fire-affected waters may impact dissolved black carbon measurements.

Dissolved black carbon (DBC) is the condensed aromatic fraction of dissolved organic matter produced during wildfire and the burning of biomass. In our lab, we measure DBC concentrations following the benzenepolycarboxylic acid (BPCA) method, which oxidizes condensed aromatic carbon to BPCA molecular markers for quantification. Since “free” BPCA molecules have been identified in fire-affected surface waters and in leachates of burned soils and wildfire ash, we were curious to know if the free BPCAs would survive the sample preparation and analytical procedures, thus contributing to overall DBC concentrations.

A new paper, led by Riley Barton, shows that free BPCAs could be recovered in detectable amounts, with the most-substituted BPCAs (with 5 and 6 carboxylic acid groups) having lower percent recoveries than less-substituted BPCAs (with 3 and 4 carboxylic acid groups). The paper is entitled “The presence of free benzenepolycarboxylic acids (BPCAs) may result in the overestimation of dissolved black carbon in aqueous samples” and was published in the journal Organic Geochemistry. We conclude that DBC quantification could be impacted by free BPCAs in aqueous samples, but the degree of impact is largely dependent upon the properties of the individual BPCA molecular marker and conversion factors used.

Spotlight on undergraduate research

Ahlyia Leclerc and Nicole McDonald presented their work at the RPI Undergraduate Research Symposium!

Ahlyia Leclerc (right) presenting her poster entitled “Evolution of black carbon under differing hydrothermal conditions”.

Nicole McDonald (left) presenting her poster entitled “Investigating the graphite gradient along a hydrothermal vent chimney section”.

New paper shows that hydrology, rather than burn extent, controls carbon export after wildfire in coastal mountain rivers

Burned landscape in the Santa Cruz Mountains (California).

In a new paper, Riley Barton and her co-authors show that black carbon export is primarily driven by hydrology, rather than percentage of drainage area burned, in coastal mountain rivers recently affected by wildfire. Fieldwork for this research was conducted in watersheds located within in the Santa Cruz Mountains (California, USA). At least a portion of each of these catchments was burned during the 2020 CZU Lightning Complex Fires.

Two different streams that were sampled for this study.

In California, wildfire frequency and severity has increased five-fold over the last four decades. Coastal fires are of particular concern as regional mountain rivers facilitate rapid and direct inputs of terrestrial carbon and nutrient subsidies to marine environments. This work confirms that catchment hydrology is a major variable and must be considered in future export models that predict relationships between terrestrial wildfire characteristics and post-burn carbon fluxes.

This work is entitled “Hydrology, rather than wildfire burn extent, determines post-fire organic and black carbon export from mountain rivers in central coastal California” and was published in the journal Limnology and Oceanography Letters.

Alex Collins receives the RPI Founders Award of Excellence

Congratulations to Alex Collins who recently received the RPI Founders Award of Excellence! The prestigious award honors students who embody the qualities of creativity, discovery, and leadership, and the values of pride and responsibility at RPI.

With his research, Alex is establishing direct linkages among catchment geology, hydrologic behavior, and material export to predict changes in water quality that occur in response to climate change in northeastern US watersheds. In addition to his research accomplishments, Alex often volunteers to assist faculty and students with laboratory analyses and fieldwork and has given stream-side guest lectures as part of our departmental course offerings.

New review paper describes how ocean ecosystems respond to volcanic ash

A volcano erupting in 2019 off the coast of New Zealand. Photo by Netflix.

Volcanic eruptions can be catastrophic events, particularly when they occur in inhabited coastal environments. They also play important roles in climate and biogeochemical cycles - For example, ash and nutrient deposition may fertilize coastal surface waters, resulting in algal blooms.

Many gaps remain in addressing fundamental questions about whether volcanic ash deposition may enhance or limit both phytoplankton growth and/or drive changes in microbial community composition. In a new review paper, Sasha Wagner and co-authors outline a broad, multidisciplinary vision for monitoring volcanic eruptions near ocean ecosystems from satellites. Characteristics specific to airborne volcanic ash and ash geochemistry in seawater are also considered.

The review paper was led by Kelsey Bisson, is entitled “Observing ocean ecosystem responses to volcanic ash” and was published in Remote Sensing of Environment.

NSF RAPID grant to determine whether recent wildfires in the Yukon River Delta alter black carbon export

Charred peat moss tufts in the tundra.

Wildfires produce charcoal, also termed black carbon, which is resistant to breakdown and is environmentally long-lived. A portion of this charred material is dissolved upon interaction with water and is carried away from soils to rivers as dissolved black carbon (DBC). A warmer and drier climate has led to increased wildfire activity in Arctic regions and it is unknown how these changes will affect the amount of DBC in rivers and its fate in the coastal environment. In the summer of 2022, the Apoon Pass and East Fork Fires burned >255,000 acres in the Yukon River Delta (Alaska, USA), part of a trend towards larger and more frequent wildfires in the Delta in recent years. Sasha Wagner and her co-PIs Rob Spencer and Anne Kellerman (Florida State University) received NSF RAPID funding to determine whether recent wildfire activity in the Delta leads to increased amounts of DBC along the Yukon River and estuary to the coastal Arctic Ocean. Results of this work will lay the groundwork for future, large-scale studies on fire-derived carbon in vulnerable Arctic watersheds. This work builds upon other efforts to predict the effects of climate change on carbon cycling in Arctic-boreal landscapes and will assist in answering broad research questions regarding the behavior of DBC in intermediate reservoirs and fate of terrestrial organic matter in the coastal ocean.

Last month, Sasha Wagner and her PhD student, Maddy Miller, traveled with a small team of researchers to the village of Alukanuk to sample remote areas of the Yukon River Delta during the 2023 spring freshet, when snow and ice melt result in a large pulse of water and material from upstream to the river mouth. They spent a total of 4 days on small boats traveling to various lakes, channels, mainstem, coastal, and burned tundra sites where they collected water, soil, and charcoal samples. Over the next few months, Maddy will prepare and analyze samples for DBC and compound-specific stable carbon isotopes to assess the effects of wildfire on carbon export in the Delta. The team is grateful for the knowledge, hospitality, and support from the Alukanuk community, without whom this research would not be possible.

Left - Photo of the research team, including (from left to right) Harrison Smith (NASA), Maddy Miller (RPI), Sasha Wagner (RPI), Sonny Isadore (boat captain), Alexis Slentz (FSU), and Alyssa Burns (UC Davis). Right - Enjoying akutaq (Eskimo ice cream) in the burned tundra. So thankful for this amazing group of people!

Left - Taking progressively smaller planes out to the edge of the Yukon River Delta. Right - View of the Delta from the air.

Driving out in search of salty water - It was hard to find some because the river plume was so big!

Maddy and Alexis filtering large volumes of Yukon River water.

We saw so many moose!

Left - Look at all that lovely dissolved organic matter! Right - Sasha filtering water samples.

RILEY BARTON AWARDED THE DOE Office of Science Graduate Student Research Fellowship

Rensselaer Polytechnic Institute doctoral student Riley Barton has been selected as one of 87 outstanding graduate students in the United States by the Department of Energy’s (DOE) Office of Science Graduate Student Research Program (SCGSR).

The goal of SCGSR is to prepare graduate students for science, technology, engineering, or mathematics (STEM) careers critically important to the DOE Office of Science mission, by providing graduate thesis research opportunities through extended residency at DOE national laboratories. The awardees represent 58 different universities and will conduct research at 16 DOE national laboratories.

“This fellowship will be instrumental to my dissertation research and allow me to learn what it is like to conduct research in a government setting,” said Barton. “I’m very excited for this opportunity!”

Barton graduated from Rensselaer with a bachelor’s in chemistry and geology in May of 2020 and is now a doctoral student under Sasha Wagner, assistant professor in the Department of Earth and Environmental Sciences. Barton’s research broadly focuses on the biogeochemical cycling of organic carbon, including black carbon, in wildfire-affected aquatic systems.

The SCGSR program provides opportunities for graduate students to conduct part of their graduate thesis research at a DOE laboratory, in collaboration with a DOE laboratory scientist. Barton will perform her research at the Pacific Northwest National Laboratory (PNNL). One of the PNNL's Earth Systems Science Division’s primary goals is predicting the impacts of natural hazards such as wildfires and extreme climate events on Earth and human systems. The SCGSR research projects are expected to advance the graduate awardee’s overall doctoral thesis while providing access to the expertise, resources, and capabilities available at the DOE laboratories. At PNNL, Barton will study anhydrosugars, or low-temperature pyrogenic carbon.

“Through my collaboration with Dr. Allison Myers-Pigg, an anhydrosugar expert, I will develop a new, time-efficient, and cost-saving method for analyzing anhydrosugars in water,” said Barton. “Additionally, I will quantify anhydrosugars in water samples from coastal streams impacted by the 2020 CZU Lightning Complex Fires. I will predict the degradation and fate of both low- and high-temperature pyrogenic carbon from recently burned watersheds using a reactive transport model.”

“The SCGSR program provides a way for graduate students to enrich their scientific research by engaging with researchers at DOE National Labs, learning from world-class scientists and using state-of-the-art equipment and facilities. In addition, they get valuable opportunities to network and observe firsthand what it’s like to have a scientific career,” said Asmeret Asefaw Berhe, director of the DOE Office of Science. “I can’t wait to see what these young researchers do in the future. I know they will meet upcoming scientific challenges in new and innovative ways.”  

Previously, Barton was awarded the Consortium of Universities for the Advancement of Hydrologic Science Inc. Pathfinder Fellowship that supported her travel to California wildfire field sites, the Limnology and Oceanography Letters Early Career Publication Honor, Rensselaer’s Founders Award of Excellence, the Rensselaer Graduate Fellowship, and the Sigma Xi Grant in Aid of Research.

“On top of her personal achievements, Riley plays a big role in training and fostering curiosity in the next generation of young scientists. She is a welcoming and supportive mentor to the undergraduate researchers in my lab,” said Wagner.

“The RPI community is proud of Riley Barton and her early accomplishments, and we anticipate hearing about exciting advancements emanating from her research thanks to her affiliation with Pacific Northwest National Laboratory,” said Curt Breneman, dean of Rensselaer’s School of Science. “Analyzing and understanding the composition of charred materials in waterways resulting from modern wildfires opens the door to improving the predictive capability of contemporary carbon cycling and climate models.”

Read the full Rensselaer News article here: “RPI Doctoral Student One of 87 Nationwide To Receive Research Opportunity at National Lab” - Originally published by K. Malatino on 3 May 2023.

AHLYIA LECLERC AND ISABELLA WINSTON WIN FIRST AND SECOND PLACE AT THE RPI 15TH ANNUAL UNDERGRADUATE RESEARCH SYMPOSIUM

Congratulations to Ahlyia Leclerc and Isabella Winston who presented at the RPI 15th Annual Undergraduate Research Symposium last month and were awarded first and second place, respectively for best oral presentation in the Engineering and Physical Sciences category!

Ahlyia’s work was entitled “Investigating the impact of prescribed burns on black carbon concentrations in salt marsh sediments.” Ahlyia has spent the last year working to determine whether fire history affects the accumulation and storage of black carbon in Delaware coastal marsh sediments. As part of this project, Ahlyia collaborates with Andrew Wozniak and Chris Kelly at the University of Delaware. This year, Ahlyia will conduct experiments to determine how hydrothermal conditions may alter the amount and composition of black carbon in sediments and other environmental matrices.

Isabella’s work was entitled “Do naturally occurring benzenepolycarboxylic acids affect the measurements of dissolved black carbon?” Isabella has worked closely with Riley Barton on this project, which seeks to determine whether benzenepolycarboxylic acids that occur naturally in soils, wildfire ash, and post-fire surface water could result in an overestimation of black carbon in environmental samples. Isabella will continue her research as part of the Wagner lab in the upcoming year.

New review paper describes the role of black carbon in the Earth system

Climate feedback loops for wildfire and associated black carbon (BC) production - Figure from Coppola et al. (2022)

In a new review paper, Sasha Wagner and co-authors describe the role of black carbon (BC) in the Earth system and its importance with regards to carbon sequestration and climate feedback loops. Wildfires are the main source of BC, producing roughly 130 million tons of refractory (relatively unreactive) carbon per year. As the occurrence of wildfire increases with anthropogenic warming, the production and long-term storage of BC could act as a negative climate feedback that offsets (counteracts) some portion of carbon dioxide emissions. However, the magnitude of these effects are currently unknown.

To account for the role of BC in Earth System Models and future climate scenarios, we must work towards a comprehensive understanding of regional and global BC stocks and fluxes. Key research questions include:

• What is the chemical identity of BC?

• What are the major pathways and rates for BC decomposition in soils, floodplains, and inland water bodies?

• If not all BC is produced on land, what are the sources of BC in the ocean?

The review paper was led by Alysha Coppola, is entitled “The black carbon cycle and its role in the Earth system” and was published in Nature Reviews Earth and Environment.