ARCHIVED CONTENT: In December 2020, the CZO program was succeeded by the Critical Zone Collaborative Network (CZ Net) ×

Cross-CZO Studies

A goal of the CZO program is to catalyze transformative Earth surface science

in the coming decade by developing cross-CZO science that helps to establish:

a unifying theory of CZ evolution;
coupled systems models to explore how CZ services respond to anthropogenic, climatic, and tectonic forcing;
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

CZO National cross-network activities.

The nine CZOs together have proposed the following activities to facilitate and promote cross-site science among the CZOs.

CZ Network Cyberseminar Series. The CZOs will work to run six cyberseminars/yr. Seminars will follow the following framework; all viewers can see the slides; the speaker can point and annotate, and participants can comment and question by voice or text. This cyberseries will build upon the series of six talks run for CZO by CUAHSI in 2011-2012. In the next 5 years, we will highlight scientists, postdocs, and students working on CZ questions, including those that are not a member of a CZO team. In some cases, a cyberseminar may be scheduled as follow-up after one of the cross-network activities outlined below. All CZ topics will be included.

CZ Network Research (CZNR) Workshops. Each observatory will run one ~2.5-day CZNR Workshop on an interdisciplinary topic. Workshop size will be ~12 scientists and students from in and outside of the CZO network. Each CZO host will provide travel allowances, housing, and meals. The intent is to stimulate researchers to work together and across disciplines. The broadly advertised workshops will result in a proposal, synthesis paper, or integrative model. CZO data will be highlighted appropriately in the context of data from other sites.

Drill-the-Ridge. Access to the bottom of the weathered rock zone is difficult to gain but is widely recognized as the CZ region we understand the least. In recognition of this, the CZO network produced a special issue in Earth Surface Processes and Landforms, and ran a special session at AGU. Pilot coring projects have been run at all six original CZOs, and will be extended. The idea, called “Drill the Ridge” was proposed at the International Workshop on Design of Global Environmental Gradient Experiments using International CZO Networks (8-9 Nov 2011, University of Delaware). The goal at each site will be to reach the water table and fresh rock, typically by wireline drilling, extracting core and overburden. Downhole logging will also be pursued, i.e., electrical logging, calipers, acoustic televiewer, optical televiewer, compensated density caliper, thermal neutral (relative porosity), heat pulse flowmeter, and hydrophysical logging. If possible, the borehole will be completed as a well, and instrumented with water level and temperature sensors, and will be used to collect water samples monthly using the method of choice (bailing or pump) at each site. These pilot coring projects will provide training for students in drilling technologies. The data from this initial Drill-the-Ridge campaign will provide preliminary data to be used to inform future proposals to core in more locations, with accompanying geophysical surveys, pump testing, and microbiological sampling. The depth of these initial pilot holes will vary from site to site. Holes will vary from 10 to 300 m in depth.

Joint Research Field Campaigns. All observatories will run three 5-day CZ Joint Research Field Campaigns spread over the next five years. Each site will host one field campaign, similar in format but with different foci. The host will support travel and accommodation for a total of 12 students, postdocs or scientists from other CZOs in each campaign. The intent is to stimulate researchers to develop shared data, to work together across disciplines, and to introduce students to new sites and techniques. It is expected that results from each Campaign will become part of the CZO community data resources. If appropriate, the CZOs may use the CZ Network Research Workshops to develop focused questions for the field campaigns, or for the CZ Network Research Workshops.

Cross-CZO modeling. Ongoing modeling activities at each of the CZOs will be communicated and integrated across the network through a series of cross site visits to other CZOs. During those visits, modelers will be cross-fertilized in terms of conceptualizations and codes and will learn how to make best use of available data. To facilitate this effort, each CZO will support travel to enable modelers to visit or travel to other CZOs.

NSF Division of Earth Sciences (EAR) Postdoctoral Fellowships have been awarded to scientists working to develop cross-CZO research programs.

Jill Marshall

Jill Marshall of the University of Oregon has been recently awarded an NSF postdoctoral fellowship for her cross-CZO proposal: Cracking the critical zone: Tree roots in fractures and a proposed mechanistic soil production function. The study’s overarching objective is to parameterize and calibrate a soil production function (a geomorphic process law) for forested landscapes based on observations of the mechanics of root-driven bedrock damage and detachment. The lack of a mechanistic bedrock to soil production function has hampered progress on a broad array of problems in critical zone science. This project will enable numerical experiments that explore how the presence and absence of vegetation control surface and near-surface processes and landscape form. Project mentors are Dr. William Dietrich (Director Eel River CZO), UC Berkeley (primary host institution), and Dr. Robert Anderson (Investigator Boulder Creek CZO), University of Colorado. Jill will start research during mid-summer 2015, working at the Eel River, Boulder Creek, and Southern Sierra CZOs where she can take advantage of the three CZO’s exposed roots in bedrock fractures, and site-specific differences in climate-driven rock-water availability and rock properties.

Read about more cross-CZO work of previous fellowship recipients: Dr. Adrian Harpold and Dr. Diana Karwan

Jill Marshall