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.
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.
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:
02 Nov 2017 - UC Merced scientists are sharing their research, stories, and expertise at Merced City School District's new STEAM Center.
30 Oct 2017 - Water Resources Research published a new special collection in September 2017 featuring concentration-discharge research from multiple CZOs.
21 Jun 2017 - University of California Television (UCTV) features Bales, Conklin, Glaser, Safeeq, and others on the new Sustainable California channel
04 May 2017 - Onward California - University of California television spots showcase Southern Sierra CZO research
21 Apr 2017 - AGU has published a collection of commentaries highlighting the important role Earth and space science research plays in society.
06 Apr 2017 - 2017 CZO Webinar Series: Critical Zone and Society.
28 Mar 2017 - NSF Press Release: New research finding provides insight into role dust may play as ecosystems change
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.
06 Nov 2017 - By Michelle Gilmore and Leigh Bernacchi Ever wonder how we know what we know about water? Twenty-five intrepid water and forest managers,...
03 Oct 2017 - Five master's students at the UCSB Bren School are incentivizing restoration strategies for private landholders with Sierra RCD.
19 Jul 2017 - 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.
28 Mar 2017 - A team of researchers found that dust provides a much greater amount of nutrients to vegetation in the Sierra Nevada than previously thought.
20 Dec 2016 - Lawrence Livermore and UC Merced researchers are tracking water through the critical zone using cutting-edge technology and new collection methods.
Growing new generations of critical zone scientists. Wymore Adam S., Nicole R. West, Kate Maher, Pamela L. Sullivan, Adrian Harpold, Diana Karwan, Jill A. Marshall, Julia Perdrial, Daniella M. Rempe and Lin Ma (2017): Earth Surface Processes and Landforms 42 (14): 2498-2502 Cross-CZO National
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 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
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 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
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 Cross-CZO
Influence of terrain aspect on water partitioning, vegetation structure, and vegetation greening in high elevation catchments in northern New Mexico. Zapata-Rios X., Brooks P.D., Troch P.A., McIntosh J. and Guo Q. (2016): Ecohydrology 9(5): 782-795 Cross-CZO National
Hydrological partitioning in the critical zone: Recent advances and opportunities for developing transferable understanding of water cycle dynamics. Brooks P.D., Chorover J., Fan Y., Godsey S.E., Maxwell R.M., McNamara J.P., and Tague C. (2015): Water Resources Research 51 (9): 6973-6987 Cross-CZO
Global patterns of dust and bedrock nutrient supply to montane ecosystems. Arvin, L.J.; Riebe, C.S.; Aciego, S.M.; Blakowski, M.A. (2017): Science Advances, Vol. 3, no. 12, eeao1588
Concentration-discharge relationships in headwater streams of the Sierra Nevada, California. Hunsaker, C. T., Johnson, D. W. (2017): Water Resources Research 53, 7869–7884
Snowmelt controls on concentration‐discharge relationships and the balance of oxidative and acid‐base weathering fluxes in an alpine catchment, East River, Colorado. Winnick M.J., Carroll R.W.H., Williams K.H., Maxwell, R.M., Dong, W., Maher K. (2017): Water Resources Research 53, 2507–2523 Cross-CZO National
Insights into hydrologic and hydrochemical processes based on concentration‐discharge and end‐member mixing analyses in the mid‐Merced River Basin, Sierra Nevada, California. Liu F., Conklin M.H., Shaw G.D (2017): Water Resources Research 53, 832–850
Quantifying nutrient uptake as driver of rock weathering in forest ecosystems by magnesium stable isotopes. Uhlig, D., Schuessler, J.A., Bouchez, J., Dixon, J.L., von Blanckenburg, F. (2017): Biogeosciences 14, 3111-3128
Technical report: The design and evaluation of a basin-scale wireless sensor network for mountain hydrology. Zhang, Z.; Glaser, S.D.; Bales, R.C.; Conklin, M.; Rice, R.; Marks, D.G. (2017): Water Resources Research.
The problem of predicting the particle size distribution of sediment supplied by hillslopes to rivers. Sklar, L. S., Riebe, C. S., Marshall, J. A., Genetti, J., Leclere, S., Lukens, C. L., Merces, V. (2017): Geomorphology. 277 31.