Stable Isotope Lab

• Annika Horlings, postdoc 2024
• Chloe Brashear, lab technician 2023
• Hayley Bennett, MS 2023
• Alyssa Johnson, lab technician 2021
• Abigail Thayer, PhD 2021
• Seth Kurtz, lab technician 2021
• William Skorski, MS 2020
• Daniela Meza Acosta, undergrad 2021
• Soisiri Chanin, undergrad 2021
• Lauren Eng, undergrad 2020
• Isaac Vimont, PhD 2017
• Karen Alley, PhD 2017
• Amy Steiker, MS 2018
• Caroline Alden, PhD 2013
• Emily Longano, undergrad 2013
• Jason Winokur, lab technician 2013

Earth's climate is changing due to the increase in anthropogenic greenhouse gases. The most important of these is carbon dioxide - and yet we don't fully understand fluxes of CO₂ between the biosphere, the atmosphere, and the ocean. ÌýStable isotopes are very useful for understanding these exchange processes because of fractionation: different isotopes ofÌýCO₂ move between these different pools at different rates. For instance, because plants strongly discriminate against the heavy isotope of CO₂, we can use the ratios of ¹³C and ¹²C ( δ¹³C_CO2) to estimate ocean versus land uptake of carbon dioxide.()

The INSTAAR Stable Isotope Lab has collaborated with the since 1990. This involves measuring δ¹³C_CO2 andÌýδ¹⁸O_CO2 from flasks and programmable flask packages from the Global Greenhouse Gas Reference Network. We proudly maintain the largest of stable isotopes in the world. You can . We will be updating our CO₂ isotope data soon! Contact Sylvia Michel for more information.Ìý

Methane is also a very important greenhouse gas, and the atmospheric burden of methane is increasing rapidly for reasons we don't fully understand. Because sources of methane have different isotopic signatures, we can use δ¹³C_CH4 to test hypotheses about where that increase has come from. Though fossil fuel sources of methane are a bigger fraction of emissions than we once thought, source, like wetlands or agriculture. Modeling CH₄ as well as its isotopes helps us understand the methane budget, and this will potentially guide climate-sensitive policy decisions. Read more about the utility of our measurements in by our colleague Sourish Basu, or by Xin Lan.

The INSTAAR Stable Isotope Lab has been measuring δ¹³C_CH4 of methane in cooperation with NOAA GML since 1998 and we have the largest collection of in the world. We work closely with collaborators around the world making similar measurements to improve our data compatability.

On Earth's great ice sheets, Greenland and Antarctica, snow accumulates over many thousands of years creating a repository of precipitation back in time. Stable isotopes of precipitation are, among other parameters, a proxy for temperature when the precipitation formed. The snow preserved in ice cores thus makes them rich paleoclimate archives. In addition, ice cores preserve records of atmospheric gases, chemistry, and physical properties, and they are unique for their combination of high resolution and long time scales. Understanding the climates of the past is essential for predicting the Earth’s responses to human-caused climate change, and ice cores are invaluable in this effort.Ìý

For more than 30 years, the Stable Isotope Laboratory has been involved in ice core projects in Greenland ( and ), Antarctica ( and , and also in the high-altitude tropics (Ecuador, Peru, Tibet). Although in the past we used isotope ratio mass spectrometry to measure the stable isotopes of ice, we now use a custom-built continuous melter system connected to a Picarro cavity ring-down mass spectrometer. This allows higher-than-ever measurement resolution of our analyses. In addition to the stable isotope analysis, we are involved with the coring,Ìýprocessing, and modeling/analysis of the data.

Most recently our efforts have focused on the , located approximately at 2,720 meters altitude ~75°N , 36°W in NE Greenland on an ice stream that moves about 1 meter/week! The multiyear project to recover ice that gives us insights into climate variability over the last 100,000 years has over a dozen international partners.Ìý

Ice cores from Antarctica can take us back even further in time. Learn more about our work with.Ìý

Ìý

In the world of ice cores, we make the assumption that the isotopic composition of the ice sheet represents the precipitation that fell over Greenland in the past. Is that true or could sublimation affect the stable isotope composition of the snow/ice? Does sublimated vapor leave the ice sheet system and what does that mean for its mass balance? At the Stable Isotope Laboratory, we work to answer these questions by taking a closer look at the water vapor isotopes above the ice sheet. By using a large fixed-wing Uncrewed Aerial System (UAS) or drone, we meet the vapor on its terms. At the field camp, we profile the atmosphere up to 1500 m above the ice sheet and capture water vapor for isotopic analysis. By looking at that information, we glean insights into the hydrological cycle of Greenland and can challenge assumptions made about its dynamics. For more information, take a look at .

This work involves many hands. Here at the Stanle Isotope Lab, you can find Kevin Rozmiarek, Bruce Vaughn, Valerie Morris, and Tyler Jones working on water vapor. Past team members Chloe Brashear, Hayley Bennett, and Will Skorski spent time in the field flying with us. Our UAS operations are enabled and empowered at CU through Director of Flight Operations Daniel Hesselius. Our work is funded by the National Science Foundation.

As much as 50% of the world's soil carbon is sequestered in the northern boreal latitudes in perennially frozen ground or permafrost. Current and future carbon emissions from these stocks are unknown, largerly due to the spatial gaps in observations and uncertainties in the mechanics of methane and carbon dioxide production. At the Stable Isotope Lab we are working toward building observation systems that enable new understanding of the way carbon is introduced into the atmosphere using our fixed-wing Uncrewed Aerial System (UAS, or drone). At our field site close to permafrost emission sources in Alaska we measure methane and soil moisture directly from the drone. We also collect multispectral images and air samples for methane-isotope analysis. We use these data to constrain isotope-enabled biogeochemisty models that inform the future of carbon release from permafrost and ultimately, the future of climate.

At the Stable Isotope Lab you'll find Kevin Rozmiarek, Tyler Jones, Bruce Vaughn, Valerie Morris, and Paloma Siegel all working on permafrost. Our UAS operations are enabled and empowered at CU through Director of Flight Operations Daniel Hesselius. This work is funded through the National Science Foundation's Navigating the New Arctic program and with lab partner .

The Mobile Methane Analyzer. Photo by Christi Turner.

Visual display of a mobile methane sampling along roads in Weld County.Ìý

The Stable Isotope Lab participated in the CU-based, NSF funded Sustainability Research Network called the Air Water Gas project which is aimed at studying the oil and gas industry in the Rocky Mountain West. The mission of this project was to provide a logical, science-based framework for evaluating the environmental, economic, and social trade-offs between development of natural gas and protection of water and air resources. The project educated the public and influenced the development of policies and regulations governing natural gas and oil development.

Unlike all of our lab-based measurements, mobile methane measurements are recorded on the fly as the vehicle drives. The data are plotted onto an interactive map and Landsat images.

• Sample VolumeÌýFirst line is amount needed for analyses; second line is the desired amount of sample to be submitted, to allow enough for replicate analyses.
• PrecisionÌýis the long term reproducibility (one sigma) of a known-unknown.
• Cost Per AnalysisÌýis an estimate for off-campus non-academic research, including commercial parties and governmental agencies. Prices are lower for academic projects and university research. Assistance with interpretation of data is available. We do not attempt to compete with commercial labs.
• Analysis timeÌýis an average turnaround time for a small number of samples (1-50). Actual time may be shorter or longer depending on machine performance, barring mechanical failures beyond our control.

Notes

• We will bill your university/party/agency after the work is completed. (Most universities pay with a purchase order or credit card).
• We strongly support student projects, both graduate and undergraduate. If you have a limited number of samples, and an even more limited source of funding, we may be able to help.
• PLEASE DO NOT SEND SAMPLES BY STANDARD US POSTAL SERVICE. Choose a street delivery service such as FedEx, UPS, etc.Ìý

Ìý

Tendi is a Thermo 253 Plus dual inlet isotope ratio mass spectrometer that measures the stable isotopes of carbon and oxygen in atmospheric CO₂. Tendi is connected to a Protium ORXY system that extracts CO₂ from air. Once the CO₂ has expanded into the sample bellows it is iteratively analyzed against a reference gas (in the reference bellows). Tendi mainly analyzes flasks and cylinders as part of the NOAA Global Greenhouse Gas Reference Network.

T'Pol is a GV Isoprime dual inlet mass spectrometer dedicated to running isotopes of CO₂ from programmable flask packages. These sample air along vertical gradients from tall towers and aircraft. CO₂ is extracted using a system built in-house by SIL staff that pulls air through a water trap suspended in cooled ethanol followed by the CO₂ trap in a liquid nitrogen bath. The CO2 is then heated and released into the sample bellows and analyzed against the reference bellows gas.

Ìý

Amos is also a GV Isoprime dual inlet mass spectrometer with a similar extraction system as T'Pol. It is primarily devoted to measuring air from flasks as part of the NOAA Global Greenhouse Gas Reference Network. Amos came to us pre-loved and therefore is the only instrument in our lab not named for a Star Trek character.

Troi measures carbon isotopes of methane. Since there is not enough methane in a network flask to measure using dual inlet techniques we rely on continuous flow measurements where the sample moves on a stream of helium gas. Methane and other gases are frozen on a pre-concentrator of hayesep-D, cryo-focused, and separated on a GC column. The methane is combusted to CO₂, and then the sample is "sniffed" from an open split into the mass spectrometer.

Ìý

Crusher is measuring hydrogen isotopes of methane. This measurement is challenging due to the high-temperature pyrolysis furnace which converts CH₄ to H₂ gas.

Julian and Phlox are Picarro cavity ring-down mass spectrometers dedicated to measuring hydrogen and oxygen isotopes of water from discreet samples.

Ìý

Kes measures water isotopes from ice-cores. Kes and its introduction system represent a breakthrough in our ability to obtain high resolution records from ice cores. Sections of ice cores are melted continuously and the water is moved by peristaltic pumps through a de-bubbler, a splitter (where a portion of the sample is archived), and a nebulizer. The sample is then vaporized and measured by cavity ring-down mass spectrometry.

Ìý