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.
18 Mar 2020 (National, Boulder, Calhoun, Catalina-Jemez, Eel, IML, Luquillo, Reynolds, Shale Hills, Sierra) - The U.S. CZO Program presents the 2020 CZO Webinar Series to highlight research findings of CZOs and discuss the impact and relevancy of their...
19 Nov 2019 (National, Boulder, Calhoun, Catalina-Jemez, Eel, IML, Luquillo, Reynolds, Shale Hills, Sierra) - A list of CZ-related sessions, abstracts and events at the 2019 AGU Fall Meeting.
08 Jul 2019 (National, Boulder, Calhoun, Catalina-Jemez, Christina, Eel, IML, Luquillo, Reynolds, Shale Hills, Sierra) - CZO will end Nov 2020, succeeded by the “CZ Collaborative Network”. Let’s explore how the CZ community can build upon the CZOs via new NSF proposals.
12 Jun 2019 (Calhoun, Shale Hills) - Five students travelled to Union, South Carolina for a two-day site visit June 6 – June 8 at the Calhoun CZO. This site visit was the...
31 May 2019 (Calhoun) - Mac Callaham and his group shared their research on earthworms at the May 2019 Society for Freshwater Science annual meeting in Salt Lake City.
31 May 2019 (Eel) - Scientists link vegetation mosaics in California to patterns of weathered bedrock.
18 May 2019 (Shale Hills) - Fifteen undergraduates from seven regional institutions arrived at University Park, along with graduate student mentors and faculty experts, to...
10 May 2019 (Shale Hills) - The 2019 All-Hands Meeting brought together our core team, our off-campus collaborators, and our outreach partners at Shaver's Creek in a new...
Where is the bottom of a watershed?. Condon L.E., Markovich K.H., Kelleher C.A., McDonnell J.J., Ferguson G., and McIntosh J.C. (2020): Water Resources Research 56(3): e2019WR026010 (Catalina-Jemez)
Quantification of Mixed-Layer Clays in Multiple Saturation States Using NEWMOD2: Implications for the Potassium Uplift Hypothesis in the SE United States. Austin, J.C., Richter, D.D. & Schroeder, P.A. (2020): Clays and Clay Minerals (Calhoun)
Digging deeper: what the critical zone perspective adds to the study of plant ecophysiology. Dawson, T.E., Hahm, W.J., & Crutchfield-Peters, K. (2020): New Phytologist (Eel)
Temporal dynamics of migration‐linked genetic variation are driven by streamflows and riverscape permeability. Kelson, S.J., Miller, M.R., Thompson, T.Q., O'Rourke, S.M. & Carlson, S.M. (2020): Molecular Ecology (Eel)
Resolving Deep Critical Zone Architecture in Complex Volcanic Terrain. Moravec B.G., White A.M., Root R.A, Sanchez A., Olshansky Y., Paras B.K., Carr B., McIntosh J., Pelletier J.D., Rasmussen C., Holbrook W.S., Chorover J. (2020): Journal of Geophysical Research: Earth Surface 125(1): e2019JF005189 (Boulder, Catalina-Jemez, Eel, Reynolds, Sierra) Cross-CZO
Bundled Causal History Interaction. Jiang, P., and Kumar, P. (2020): Entropy (IML)
A new dynamic wetness index (DWI) predicts soil moisture persistence and correlates with key indicators of surface soil geochemistry. Li, M., Foster, E.J., Le, P.V.V., Yan, Q., Stumpf, A., Hou, T., Papanicolaou, A.N., Wacha, K.M., Wilson, C.G., Wang, J., Kumar, P., and Filley, T. (2020): Geoderma (IML)
Winter CO2 efflux from sagebrush shrublands distributed across the rain‐to‐snow transition zone. Fellows, A.W., Flerchinger, G.N., Seyfried, G.N., Biederman, J.A.. and K.A. Lohse (2020): JGR Biogeosciences (Reynolds)
Understanding the effect of fire on vegetation composition and gross primary production in a semi-arid shrubland ecosystem using the Ecosystem Demography (EDv22) model. Pandit, K., Dashti, H., Hudak, A.T., Glenn, N.F., Flores, A.N., and D.J. Shinneman (2020): Biogeosciences Discuss. (Reynolds)
Debates—Does Information Theory Provide a New Paradigm for Earth Science?. Kumar, P. and Gupta, H.V. (2020): Water Resources Research (IML)
Debates—Does Information Theory Provide a New Paradigm for Earth Science? Causality, Interaction, and Feedback. Goodwell, A.E., Jiang, P., Ruddell, B.L., and Kumar, P. (2020): Water Resources Research (IML)
The impact of tillage row orientation on physical and chemical sediment enrichment. Wacha, K.M., Papanicolaou, A.N., Abban, B.K., Wilson, C.G., Giannopoulos, C.P., Hou, T., Filley, T.R., and Hatfield, J.L. (2020): Agrosystems, Geosciences, and Environment (IML)