Spatial differences along the elevation gradient characterizing our Critical Zone Observatory's field areas - from forest ecology to preciptation phase to bedrock composition - create a natural laboratory to study changes in critical zone characteristics and processes across the landscape. While this elevation transect experiences rapid seasonal changes, from snow cover to wet soil to dry soil in a 1-2 month period, climate warming will shift this transition to an earlier time and a higher elevation. Researchers can also use the gradient then as a substitution of space for time to research how critical zone processes respond to natural and anthropogenic environmental changes, including warmer average temperatures and forest thinning.
Our growing community of critical zone scientists from multiple institutions and areas of research expertise are carrying out investigations in the Sierra National Forest, Kings River Experimental Watershed, San Joaquin Experimental Range, and Sequoia National Park.
Learn more about our field areas and instrumentation -->
Conduct research at our CZO -->
Critical Zone researchers are currently investigating a tightly linked set of research questions at our Observatory, including:
While some research is centered on a single discipline, many questions require a multi-disciplinary approach. Our measurements and monitoring efforts overlap with other observatories in the National Science Foundation's U.S. Critical Zone Observatory Network in order to rapidly improve Earth systems models.
Explore examples of current research topics in detail -->
Since it was initiated in 2007, the Southern Sierra CZO has become a platform for a wide variety of research. Much of the research during the first five years addressed these questions:
Among the many results to date at our CZO, four key findings stand out:
24 Nov 2020 - More news about SSCZO on Center for Ecosystem Climate Solutions, which grew out of the SSCZO, also on Sustainable California
24 Nov 2020 - This film, plus our 90-minute documentary Beyond the Brink, are also available at https://www.beyondthebrink.global/
27 Oct 2020 - They’re beneath our feet, but we seldom hear important signals in the soils
17 Jun 2020 - For an updated listing of these talks, including abstracts, see /national/education-outreach/sustainability-2020/ The U.S....
04 May 2020 - Onward California - University of California television spots showcase Southern Sierra CZO research
19 Nov 2019 - A list of CZ-related sessions, abstracts and events at the 2019 AGU Fall Meeting.
08 Jul 2019 - 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.
19 Nov 2018 - The 2018 AGU Fall Meeting will be held December 10-14 in Washington, D.C.
11 May 2018 - Too many trees in Sierra Nevada forests stress water supplies, scientists say
10 May 2018 - The Discoveries section of the National Science Foundation's website on Critical Zone Observatories (CZOs).
22 Mar 2018 - NSF Southern Sierra CZO researchers peer into North America’s West Coast salmon rivers
21 Jun 2017 - University of California Television (UCTV) features Bales, Conklin, Glaser, Safeeq, and others on the new Sustainable California channel
11 Apr 2016 - New York Times reporter, Henry Fountain spoke with Southern Sierra CZO PIs Roger Bales and Martha Conklin and investigtor Mohammad Safeeq as they...
07 Sep 2015 - Get a sense of the people and the work. Several members of the Southern Sierra CZO are profiled here, including students and professors.
14 Nov 2018 - Say 'Hello!' to biogeochemist Morgan Barnes! Morgan specializes in the study of soil nutrient biogeochemistry, focusing on phosphorus in the Sierras
06 Nov 2018 - Marshall Receives 2018 Luna B. Leopold Young Scientist Award
24 Oct 2018 - Meet forest ecologist Jeff Lauder! Lauder's research focuses on Sierra Nevada Conifers and how they have been responding to stress during drought!
12 Sep 2018 - Two postdoctoral scholar positions and multiple MS or PhD research assistantships are currently available at the University of California, Merced....
07 Sep 2018 - Recent activities and findings, funding opportunities, upcoming events, and other updates
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 Cross-CZO
Ecological and genomic attributes of novel bacterial taxa that thrive in subsurface soil horizons. Brewer, Tess E., Emma L. Aronson, Keshav Arogyaswamy, Sharon A. Billings, Jon K. Botthoff, Ashley N. Campbell, Nicholas C. Dove, Dawson Fairbanks, Rachel E. Gallery, Stephen C. Hart, Jason Kaye, Gary King, Geoffrey Logan, Kathleen A. Lohse, Mia R. Maltz, Emilio Mayorga, Caitlin O’Neill, Sarah M. Owens, Aaron Packman, Jennifer Pett-Ridge, Alain F. Plante, Daniel D. Richter, Whendee L. Silver, Wendy H. Yang, Noah Fierer (2019): mBio Oct 2019, 10 (5) e01318-19 Cross-CZO National
Southern Sierra Critical Zone Observatory and Kings River Experimental Watersheds: A Synthesis of Measurements, New Insights, and Future Directions. O'Geen, A.; Safeeq, M.; Wagenbrenner, J.; Stacy, E.; Hartsough, P.; Devine, S.; Tian, Z.; Ferrell, R.; Hopmans, J.W.; and Bales, R. (2018): Vadose Zone Journal, 17:180081
Mercury sourcing and sequestration in weathering profiles at six Critical Zone Observatories. Richardson, Justin B., Arnulfo A. Aguirre, Heather L. Buss, A. Toby O'Geen, Xin Gu, Daniella M. Rempe, and Daniel deB. Richter (2018): Global Biogeochemical Cycles, 32(10):1542-1555 Cross-CZO National
Ideas and perspectives: Strengthening the biogeosciences in environmental research networks. Richter, D.D., S.A. Billings, P.M. Groffman, E.F. Kelly, K.A. Lohse, W.H. McDowell, T.S. White, S. Anderson, D.D. Baldocchi, S. Banwart, S. Brantley, J.J. Braun, Z.S. Brecheisen, C.W. Cook, H.E. Hartnett, S.E. Hobbie, J. Gaillardet, E. Jobbagy, H.F. Jungkunst, C.E. Kazanski, J. Krishnaswamy, D. Markewitz, K. O’Neill, C.S. Riebe, P. Schroeder, C. Siebe, W.L. Silver, A. Thompson, A. Verhoef, G. Zhang (2018): Biogeosciences 15: 4815-4832 Cross-CZO National
Prevalence and magnitude of groundwater use by vegetation: a global stable isotope meta-analysis. Jaivime Evaristo and Jeffrey J. McDonnell (2017): Scientific Reports 7 Cross-CZO National
Special issue of The Earth Scientist about the Critical Zone and the US NSF Critical Zone Observatory (CZO) program. CZO Education/Outreach team (2016): The Earth Scientist, Volume XXXII, Issue 3, Fall 2016 Cross-CZO National
Watersheds dynamics following wildfires: Nonlinear feedbacks and implications on hydrologic responses. Maina, F.Z.; Siirila‐Woodburn, E.R. (2019): Hydrological Processes, 34 (1)
Plant Accessible Water Storage Capacity and Tree-Scale Root Interactions Determine How Forest Density Reductions Alter Forest Water Use and Productivity. TAGUE, C.L., & M.A. MORITZ (2019): Frontiers in Forests and Global Change
California forest die-off linked to multi-year deep soil drying in 2012–2015 drought. GOULDEN, M.L. & R.C. BALES (2019): Nature Geoscience, 12
The changing water cycle: The eco-hydrologic impacts of forest density reduction in Mediterranean (seasonally dry) regions. TAGUE, C.L., MORITZ, M., HANAN, E (2019): WIREs Water
Fight or Flight? Tradeoffs Between Drought Defense and Reproduction in Conifers. LAUDER, J.D. E. V. MORAN, S. J. HART (2019): Tree Physiology
Water residence time (age) and flow path exert synchronous effects on annual characteristics of dissolved organic carbon in terrestrial runoff. JEPSEN, S.M., T.C. HARMON, S. SADRO, B. REID, S. CHANDRA (2019): Science of the Total Environment
Toward Better Understanding of Terrestrial Processes through Long-Term Hydrological Observatories (Introduction to Special Section: Hydrological Observatories). BOGENA, H.R., T. WHITE, O. BOUR, K.H. JENSEN (2019): Vadose Zone Journal, 17, 1
research | Research Foci | Multiple Disciplines | Cross-CZO Studies