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.  Stable isotopes are very useful for understanding these exchange processes because of fractionation: different isotopes of CO₂ 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.(Learn more about why isotopes are useful for understanding sources and sinks of carbon!)

The INSTAAR Stable Isotope Lab has collaborated with the NOAA Global Monitoring Laboratory since 1990. This involves measuring δ¹³C_CO2 and δ¹⁸O_CO2 from flasks and programmable flask packages from the Global Greenhouse Gas Reference Network. We proudly maintain the largest dataset of stable isotopes in the world. You can visualize the data here. We will be updating our CO₂ isotope data soon! Contact Sylvia Michel for more information. 

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, studies have shown that the rapid increase is primarily from a biogenic 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 this recent publication by our colleague Sourish Basu, or this one 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 data 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. 

For more than 30 years, the Stable Isotope Laboratory has been involved in ice core projects in Greenland (NEEM and Renland), Antarctica (WAIS Divide and South Pole), 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, processing, and modeling/analysis of the data.

Most recently our efforts have focused on the East Greenland Ice Project, 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. 

Ice cores from Antarctica can take us back even further in time. Learn more about our work with Antarctic ice cores from our latest paper in Nature. 

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 East Greenland Ice Project 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 our most recent publication.

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 Sandia National Laboratories.

The Mobile Methane Analyzer. Photo by Christi Turner.

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

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 Volume First line is amount needed for analyses; second line is the desired amount of sample to be submitted, to allow enough for replicate analyses.
• Precision is the long term reproducibility (one sigma) of a known-unknown.
• Cost Per Analysis is 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 time is 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.