By: Mallory Ladd, NSF Graduate Research Fellow, at Oak Ridge National Laboratory with Stan Wullschleger, Climate Change Science Institute, Environmental Sciences Division, Oak Ridge National Laboratory
High-latitude regions of the world have experienced the greatest warming in recent decades and are projected to warm at a rate twice that of the global average in the coming century. The implications of such warming include disappearance of sea ice, coastal erosion, permafrost thaw and microbial decomposition of vulnerable soil organic matter, and changes in surface and groundwater storage. There are far-reaching consequences of these changes not only for local communities, but for regional and global climate as well.
Research teams are increasingly addressing these concerns through an interdisciplinary approach that brings together expertise from a wide variety of research disciplines. This can be seen in several high-visibility initiatives launched in recent years including Changing Permafrost in the Arctic and its Global Effects in the 21st Century (PAGE21), the Permafrost Carbon Network (PCN), the Arctic Boreal Vulnerability Experiment (ABoVE), and the Next-Generation Ecosystem Experiments (NGEE Arctic) project, which is sponsored by the Department of Energy's Biological and Environmental Research (BER) program. This latter effort is focused on field and laboratory investigations that accelerate predictive understanding of Arctic ecosystems and the inclusion of that knowledge into Earth System Models (see: "Next-Generation Ecosystem Experiment Examines Arctic Landscape's Response to Climate Change" in Witness the Arctic Spring, 2013).
In the NGEE Arctic project, just as with other interdisciplinary activities, there are opportunities and challenges for early career scientists. For example, Mallory Ladd, a National Science Foundation graduate research fellow at Oak Ridge National Laboratory, studies analytical chemistry and its applications to climate science. Ladd's current research involves developing state-of-the-art mass spectrometry techniques that can measure low-abundance, dissolved organic nitrogen compounds from the soil that are vital to plant productivity and microbial decomposition in the Arctic. The high-resolution chemical information obtained from these experiments is then used to help parameterize fine-scale biogeochemical models of nitrogen uptake and distribution, in turn helping us to better understand what controls carbon storage in these systems.
In developing her dissertation work, Ladd regularly meets with chemists, biologists, ecosystem ecologists, and computer scientists to discuss data integration and knowledge gaps in the various disciplines. This interdisciplinary approach "has strengthened my ability to communicate complex information in different ways early on in my career. It has also made me more aware of the capabilities of other disciplines and has helped me better understand and respect the language and research methods of these other areas," she said. One challenge she has run into is to make sure she designs her laboratory experiments to produce data that aligns with both the field measurements and models generated by the NGEE Arctic project. Ladd also emphasizes that the interdisciplinary atmosphere of the project, which involves more than 125 scientists from multiple institutions, has motivated her to better understand her science from different perspectives, and to be creative and flexible in forming new research questions.
Lydia Smith, a graduate student and doctoral candidate who studies terrestrial biogeochemistry at Lawrence Berkeley National Laboratory, has also benefitted from the interdisciplinary research environment of the NGEE Arctic project. She uses close collaborations with geophysicists, microbiologists, hydrologists, and plant physiologists to inform all stages of her research. Smith has used geophysical data from permafrost-dominated landscapes to design trace gas and isotope measurement schemes; leveraged integrated microbial, geochemical and hydrological data to explain profile-scale observations of CO2 and CH4 emissions; and linked 1D point measurements to broader landscape processes.
In thinking about her experience working with multiple disciplines, Smith said "A challenge for interdisciplinary research is that sampling schemes are often designed according to disciplinary knowledge and questions, which can yield spatially disconnected datasets and incompatible measurement scales." With this challenge in mind, she found that interdisciplinary research has been most successful when different teams organize data collection around common questions and then work to bridge both spatial and temporal scales. By co-locating measurements of stable carbon isotopes and microbial metatranscriptomes, for example, her team has successfully resolved microbial metabolic processes along vertical soil profiles and among microtopographic features across polygonal tundra. By then relating these point measurements to spatially-integrated hydrological and geochemical data, they found that 3D lateral transport helped explain the spatial distribution of these processes. "We would not have made those connections if we had worked within typical disciplinary boundaries," Smith said.
The interdisciplinary approach influences not only field and laboratory scientists, but computer modelers too. For Los Alamos National Laboratory Staff Scientist Ethan Coon, a computational mathematician working on high-resolution modeling of permafrost degradation who began working on the NGEE Arctic project as a postdoctorate research associate, interdisciplinary collaborations are a part of daily work. Coon leads development of the Arctic Terrestrial Simulator, a code that brings together field data from NGEE Arctic field sites, physical process representations from theorists on the team, and mathematical and computational algorithms to predict the dynamics of permafrost under a warming climate.
The biggest difficulty for Coon is making sure that the field scientists and modelers are on the same page. "Field scientists need to know how their data contributes to a given numerical experiment, while modelers need to understand when data is representative of an entire site and how it fits in with other observations," said Coon. He emphasizes that the combined tool, however, is extremely powerful. By combining field work to set up and drive a numerical experiment with mechanistic models, simulations are being run to predict how and how quickly permafrost degrades decades into the future. Coon notes, "The entire process of field and laboratory experiments contributing knowledge to models is greatly accelerated by constant communication within the team."
The urgent nature of questions being asked in the Arctic requires a focused effort if progress is to be made in a timely manner. The formation of teams drawing expertise from many disciplines offers one approach to forging a path forward. For the early career scientist, the interdisciplinary research environment offers many rewarding opportunities, but it also requires a new way of thinking about and executing their respective science. This is true whether that research is conducted in a laboratory, the field, or a numerical simulation.
More information about NGEE Arctic is available here.