The CZOS are working toward a holistic conceptual model of critical zone evolution that couples hydrological, geochemical, geomorphic, and biological processes. Such a model must consider many spatial and temporal scales.
The CZOs are building systems models that quantitatively combine multiple processes, often spanning an entire watershed. These models typically track fluxes and storage of energy, water, carbon, sediments, and/or other materials.
The CZOs are assembling the needed infrastructure for an integrated data/ measurement foundation. This foundation will inform our theoretical framework, constrain our models, and help test hypotheses across CZOs.
Despite the Critical Zone's importance to terrestrial life and many environmental issues, it remains poorly understood. Key questions include:
There are many followup questions as well. For example:
Each Critical Zone Observatory is helping work on these fundamental questions along with numerous others. Some questions are specific to the unique characteristics of their field site and the talents of their collaborative research team. Some examples:
A key advantage of the coordinated system of Critical Zone Observatories is that it can address the biggest questions by leveraging differing environments and histories. More specifically, cross-CZO science can begin to answer questions such as:
An expressed goal of the CZO program is to catalyze transformative Earth surface science in the coming decade by developing cross-site science that helps to establish: 1) a unifying theory of CZ evolution; 2) coupled systems models to explore how CZ services respond to anthropogenic, climatic, and tectonic forcing; and 3) data sets that document differing CZ geologic and climatic settings, inform the theoretical framework, constrain conceptual and coupled systems models, and test model-generated hypotheses.
Answering fundamental questions requires much better knowledge of how physical, chemical, and biological processes in the Critical Zone are coupled and at what spatial and temporal scales. Many of these processes are highly non-linear and can range across vast scales - from atomic to global, and from seconds to eons.
To better understand how the complex processes of the Critical Zone are linked, the U.S. NSF National CZO Program employs a systems approach across a broad array of sciences. This interdisciplinary and multidisciplinary approach integrates many disciplines, especially in the geological and biological sciences. Examples include hydrology, ecology, biogeochemistry, and geomorphology.
Our systems approach across disciplines is well supported via our infrastructure. Our nine observatories span a range of climatic, geologic, and physiographic environments, from California to Puerto Rico. Each CZO is working toward a common set of resources, which will enable comparison of whole-watershed energy and mass balances across a variety of settings.
Within each CZO, scientific collaborations are common, often bringing together researchers from different institutions and crossing disciplinary boundaries. This team-based approach helps foster a strong community, which is further strengthed by graduate student involvement. Similar collaborations occur between investigators and students at different CZOs as well as with members of other US science programs. Moreover, the US CZO program also works with an international network of Critical Zone investigators and research sites.
An immediate challenge is to develop a robust predictive ability for how the structure and function of the Critical Zone evolves, including how it will respond to projected climate and land-use changes. This predictive ability must be founded on:
Over the next decade, the CZO program will produce a fundamental understanding and four-dimensional data sets that will stimulate, inspire, and test the resulting predictive models.
21 Feb 2017 (National, Boulder, Calhoun, Catalina-Jemez, Christina, Eel, IML, Luquillo, Reynolds, Shale Hills, Sierra) - 2017 CZO Webinar Series: Critical Zone and Society. The series begins with "The Most Critical CZ Problems" on February 28 at 3PM EST.
17 Jan 2017 (National) - Applications for the 2017 CZO SAVI International Scholars program are being accepted until March 13.
17 Jan 2017 (National) - Applications are being accepted for 2017 CZO SAVI Summer Interns until March 13.
06 Jan 2017 (National) - The 9th International Symposium on Ecosystem Behavior BIOGEOMON 2017 will be held August 20-24, 2017 in Litomyšl, Czech Republic.
05 Dec 2016 (National) - This workshop will be held July 24-27, 2017 at Stanford. Abstract submission deadline: February 23, 2017.
22 Nov 2016 (National, Boulder, Calhoun, Catalina-Jemez, Christina, Eel, IML, Luquillo, Reynolds, Shale Hills, Sierra) - CZOs at AGU 2016: Agenda and award recipients
26 Sep 2016 (National, Shale Hills) - Get a sense of the people and the work. Several members of the Shale Hills CZO are profiled here, including students and professors.
20 Dec 2016 (Sierra) - Lawrence Livermore and UC Merced researchers are tracking water through the critical zone using cutting-edge technology and new collection methods.
15 Dec 2016 (Sierra) - Onward California - University of California television spots showcase Southern Sierra CZO research
08 Dec 2016 (Calhoun) - Bruno Latour, anthropologist and philosopher of science, gave a talk on Critical Zone science and the Anthropocene entitled "From the Anthropocene...
23 Nov 2016 (IML) - Scientists predict that modern soybeans produce more leaves than they need to the detriment of yield—made worse by rising atmospheric CO2.
21 Nov 2016 (Calhoun) - Four soil pits were installed in new Research Area 8 at the Calhoun CZO on 21-22 November 2016 for easy access for soil sampling down to 2 meters.
Enhancing Interoperability and Capabilities of Earth Science Data using the Observations Data Model 2 (ODM2). Hsu, Leslie, Emilio Mayorga, Jeffery S. Horsburgh, Megan R. Carter, Kerstin A. Lehnert and Susan L. Brantley (2017): Data Science Journal, 16: 4, pp. 1–16 (National, Shale Hills) Cross-CZO National
Expanding the role of reactive transport models in critical zone processes. Li Li, Kate Maher, Alexis Navarre-Sitchler, JennyDruhan, Christof Meile, Corey Lawrence, Joel Moore, Julia Perdrial, Pamela Sullivan, Aaron Thompson, Lixin Jin, EdwardW. Bolton, Susan L. Brantley, William E. Dietrich, K. Ulrich Mayer, Carl I. Steefel, Albert Valocchi, John Zachara, Benjamin Kocar, Jennifer Mcintosh, Benjamin M. Tutolo, Mukesh Kumar, Eric Sonnenthal, Chen Bao, Joe Beisman (2017): Earth-Science Reviews, 165:280-301 (Calhoun, Catalina-Jemez, Eel, Shale Hills) Cross-CZO
Controls on deep critical zone architecture: a historical review and four testable hypotheses. Riebe, C. S., Hahm, W. J., Brantley, S. L. (2017): Earth Surface Processes and Landforms, 42 (1): 128–156 (National, Luquillo, Shale Hills, Sierra) Cross-CZO National
Clays in the Critical Zone: An Introduction . Paul Schroeder (2016): Clays and Clay Minerals 65 (5): 586-587 (Calhoun)
Decreasing, not increasing, leaf area will raise crop yields under global atmospheric change. Srinivasan, V., Kumar, P., and Long, S.P. (2016): Global Change Biology (IML)
Variation of organic matter quantity and quality in streams at Critical Zone Observatory watersheds. Miller, Matthew P., Boyer, Elizabeth W., McKnight, Diane M., Brown, Michael G., Gabor, Rachel S., Hunsaker, Carolyn T., Iavorivska, Lidiia, Inamdar, Shreeram, Johnson, Dale W., Kaplan, Louis A., Lin, Henry, McDowell, William H., Perdrial, Julia N. (2016): Water Resources Research, 52 (10): 8202–8216 (Boulder, Christina, Luquillo, Shale Hills, Sierra) Cross-CZO
Designing a suite of measurements to understand the critical zone. Brantley, S. L., DiBiase, R. A., Russo, T. A., Shi, Y., Lin, H., Davis, K. J., Kaye, M., Hill, L., Kaye, J., Eissenstat, D. M., Hoagland, B., Dere, A. L., Neal, A. L., Brubaker, K. M., and Arthur, D. K (2016): Earth Surface Dynamics 4: 211-235 (Shale Hills)
Controls on solute concentration-discharge relationships revealed by simultaneous hydrochemistry observations of hillslope runoff and stream flow: The importance of critical zone structure. Kim, H., W. E. Dietrich, B. M. Thurnhoffer, J. K. B. Bishop, and I. Y. Fung (2017): Water Resour. Res., 53 (Eel, Shale Hills) Cross-CZO
Critical zone properties control the fate of nitrogen during experimental rainfall in montane forests of the Colorado Front Range. Hinckley, E. S., Ebel, B. A., Barnes, R. T., Murphy, S. F., Anderson, S. P. (2017): Biogeochemistry (2017) 132: 213. doi:10.1007/s10533-017-0299-8 (Boulder)
Block-controlled hillslope form and persistence of topography in rocky landscapes. Glade, R. C., Anderson, R. S., and Tucker, G. E. (2017): Geology, First published on 2017-01-23 12:45:18, doi:10.1130/G38665.1 (Boulder)
Tropical river suspended sediment and solute dynamics in storms during an extreme drought. Clark, K.E., Shanley, J.B., Scholl, M.A., Perdrial, N., Perdrial, J.N., Plante, A.F., McDowell W.H. (2017): Water Resources Research (Luquillo)
Combined soil-terrain stratification for characterizing catchment-scale soil moisture variation. Baldwin, C., Naithani, K.J., and Lin, H. (2017): Geoderma 285:260–269 (Shale Hills)
Understanding Watershed Hydrogeochemistry: 2 Synchronized Hydrological and Geochemical Processes Drive Stream Chemostatic Behavior . Li Li, Chen Bao, Pamela L. Sullivan, Susan Brantley, Yuning Shi, Chris Duffy (2017): Water Resources Research (Shale Hills)
Understanding Hydrogeochemical Processes at the Watershed Scale: 1 Development of RT-Flux-PIHM. Bao, Chen, Li Li, Yuning Shi, Christopher Duffy (2017): Water Resources Research (Shale Hills)