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.
17 Oct 2017 (IML) - A new information partitioning methodology allows researchers to identify the factors that drive behavior in an ecohydrologic system.
17 Oct 2017 (IML) - A series of field experiments in the U.S. Midwest is investigating how past, present, & future human activities and climate affect the health of soil.
17 Oct 2017 (National) - Contribute to public discussion of a draft report: “New Opportunities for Critical Zone Science” based on the June 2017 Arlington CZO meeting.
05 Oct 2017 (National) - NSF's CTEMPs offers a two-day hands-on workshop on distributed fiber sensing. 9-10 Dec. Limited to 30 participants. Register soon!
18 Sep 2017 (National, IML) - Analysis of more than five decades of data leads to new conclusions
14 Aug 2017 (National, Catalina-Jemez) - Researchers find that carbon starvation and hydraulic failure kill drought-stricken trees.
05 Oct 2017 (Shale Hills) - Just under 250 geologists from across the state of Pennsylvania spent three days (Oct 5-7) exploring outcrops and research sites in Blair, Centre...
05 Oct 2017 (Luquillo) - Hurricane Maria ravaged Puerto Rico. The Category 4 storm destroyed thousands of homes, businesses, bridges, communication towers, the entire...
05 Oct 2017 (Luquillo) - The world’s rainforests absorb 30 percent of human-produced carbon dioxide. Plants take up the CO2 through photosynthesis and release it...
19 Jul 2017 (Sierra) - Wonder what soils and sponges have in common? Or why some trees in the Sierra Nevada are dying while others are surviving? Find out in our new comic.
13 Jul 2017 (National, Luquillo) - Researchers at NSF Critical Zone Observatory and Long-Term Ecological Research sites are finding out.
Hydrogeomorphological differentiation between floodplains and terraces. Qina Yan, Toshiki Iwasaki, Andrew Stumpf, Patrick Belmont, Gary Parker, Praveen Kumar (2017): Earth Surface Processes and Landforms (IML)
Regional sensitivities of seasonal snowpack to elevation, aspect, and vegetation cover in western North America. Christopher J. Tennant, Adrian A. Harpold, Kathleen Ann Lohse, Sarah E. Godsey, Benjamin T. Crosby, Laurel G. Larsen, Paul D. Brooks, Robert W. Van Kirk, Nancy F. Glenn (2017): Water Resources Research 53 (National, Boulder, Catalina-Jemez, Reynolds, Sierra) Cross-CZO National
Impacts of hydraulic redistribution on grass–tree competition vs facilitation in a semi-arid savanna. Barron-Gafford G.A., Sanchez-Cañete E.P., Minor R.L., Hendryx S.M., Lee E., Sutter L.F., Tran N., Parra E., Colella T., Murphy P.C., Hamerlynck E.P., Kumar P. and Scott R.L. (2017): New Phytologist 215(4): 1451–1461 (Catalina-Jemez, IML) Cross-CZO
A multi-species synthesis of physiological mechanisms in drought-induced tree mortality. Adams H.D., Zeppel M.J.B., Anderegg W.R.L., Hartmann H., Landhausser S.M., Tissue D.T., Huxman T.E., Hudson P.J., Franz T.E., Allen C.D., Anderegg L.D.L., Barron-Gafford G.A., Beerling D.J., Breshears D.D., Brodribb T.J., Bugmann H., Cobb R.C., Collins A.D., Dickman L.T., Duan H., Ewers B.E., Galiano L., Galvez D.A., Garcia-Forner N., Gaylord M.L., Germino M.J., Gessler A., Hacke U.G., Hakamada R., Hector A., Jenkins M.W., Kane J.M., Kolb T.E., Law D.J., Lewis J.D., Limousin J-M., Love D.M., Macalady A.K., Martinez-Vilalta J., Mencuccini M., Mitchell P.J., Muss J.D., O'Brien M.J., O'Grady A.P., Pangle R.E., Pinkard E.A., Piper F.I., Plaut J.A., Pockman W.T., Quirk J., Reinhardt K., Ripullone F., Ryan M.G., Sala A., Sevanto S., Sperry J.S., Vargas R., Vennetier M., Way D.A., Xu C., Yepez E.A., and McDowell N.G. (2017): Nature Ecology & Evolution 1: 1285–1291 (Catalina-Jemez)
Growing new generations of critical zone scientists. Adam S. Wymore, Nicole R. West, Kate Maher, Pamela L. Sullivan, Adrian Harpold, Diana Karwan, Jill A. Marshall, Julia Perdrial, Daniella M. Rempe, Lin Ma (2017): Earth Surface Processes and Landforms (National, Luquillo) Cross-CZO National
The temperature response surface for mortality risk of tree species with future drought. Adams H.D., Barron-Gafford G.A., Minor R.L., Gardea A.A., Bentley L.P., Law D.J., Breshears D.D., McDowell N.G., Huxman T.E. (2017): Environmental Research Letters (accepted) (Catalina-Jemez)
Photosynthetic phenological variation may promote coexistence among co-dominant tree species in a Madrean sky island mixed conifer forest. Potts D.L., Minor R.L., Braun Z., Barron-Gafford G.A. (2017): Tree Physiology 37(9): 1229–1238 (Catalina-Jemez)
Dual-phase mass balance modeling of small mineral particle losses from sedimentary rock-derived soils . Bern, Carleton R. and Yesavage, Tiffany (2017): Chemical Geology (in review) (Shale Hills)
Event-scale power law recession analysis: quantifying methodological uncertainty. Dralle, D. N., Karst, N. J., Charalampous, K., Veenstra, A., and Thompson, S. E. (2017): Hydrology and Earth System Sciences 21:65-81 (Eel)
Rise and fall of toxic benthic freshwater cyanobacteria (Anabaena spp) in the Eel river: Buoyancy and dispersal. Bouma-Gregson, K., Power, M.E., and Bormans, M. (2017): Harmful Algae 66: 79-87 (Eel)
A reactive transport model for Marcellus shale weathering. Heidari, P., Li Li, Lixin Jin, Jennifer Z. Williams, and Susan L. Brantley (2017): Geochimica et Cosmochimica Acta, 217:421-440 (Shale Hills)
Patterns of change in high frequency precipitation variability over North America. Roque-Malo, S. and Kumar, P. (2017): Nature.com (IML)