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Unit 1.1 - CZ Overview

Timothy White (Pennsylvania State University)
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This page first made public: May 15, 2017

Summary

The Critical Zone encompasses the external or near-surface Earth extending from the top of the vegetation canopy down to and including the subsurface zone of freely circulating fresh groundwater. Complex biogeochemical processes combine here to transform rock and biomass into the central component of the Critical Zone: soil. The Zone sustains nearly all terrestrial life, including humanity, nonetheless ever-increasing negative impacts of human society on the Critical Zone continue.

This lesson uses lecture, readings, and web exploration to provide students an introduction to Critical Zone science from which they should grasp key concepts outlined below. Do not fret over every detail, that will be accomplished through the remainder of the semester. This unit will stress that Critical Zone science truly is multi- and trans-disciplinary. Critical Zone processes are represented by coupled physical, biological, and chemical processes—and an array of scientific expertise in many fields including geology, soil science, biology, ecology, geochemistry, geomorphology, hydrology, and more, is needed to understand the Critical Zone.

Learning Goals

By the end of this lesson students should be able to:

  • Define the CZ and its importance to humanity.
  • Explain/give an example of the four driving questions of CZ science:
    • How do variations in and perturbations to chemical and physical weathering processes impact the CZ?
    • How do biogeochemical processes govern long-term sustainability of water and soil resources?
    • How do processes that nourish ecosystems change over human and geologic time scales?
    • What processes control fluxes of carbon, particulates, and reactive gases over different time scales?
  • Describe the main challenges and needs of an integrated national research effort focused on Critical Zone science.
    • What is the structure of the integrated national research effort that exists?
    • Who does this program serve?
  • List some general human (and other) impacts on the Critical Zone.

Context for Use

This unit will encompass a single 75 minute class meeting from which students will gain: a basic understanding of the Critical Zone, and a framework in which the remainder of the course can be understood; an Internet connection is required for the final part of the in-class activity. The Critical Zone refers to the thin outer veneer of Earth between the top of the vegetation canopy down to the deepest depths in Earth's crust at which fresh groundwater freely circulates—in effect, the zone where most terrestrial life as we know it thrives. Humanity and all terrestrial life rely on the CZ. Consider a single mechanism capable of nurturing life, supporting agriculture, cleansing water, buffering atmospheric gas levels, to name a few processes. It is this zone, or system, critical to the maintenance of healthy life on Earth, that you will learn about during this course. Interestingly, very little transdisciplinary and integrative science has been accomplished in the CZ, primarily because historically no national-level funding enabled such studies. However, the NSF has corrected this oversight through the creation and funding of the Critical Zone Observatory program. Thus you have entered an emerging realm of science, truly a frontier, in which new concepts will be advanced and new discoveries will be made as we progress through this course.

Description and Teaching Materials

Unit 1.1 Lesson Plan (one 75-min class session)

In this unit, students are primarily tasked with reading five reports (one report by each of four groups, and one chapter individually) and browsing five websites to gain some basic knowledge of Critical Zone science and observatories; a lecture (provided below) supplements these activities.

The reports include a science plan developed by the Critical Zone science community prior to the establishment of the U.S. National Science Foundation's CZO program, a National Research Council report that helped to formally guide the lead-up to the observatory program, a report that is the culmination of a workshop of international CZ scientists who identified a series of science challenges to be addressed by the CZ community in the coming decade, and an interim report on the accomplishments of CZOs to date. Combined, these reports provide basic knowledge of "what is" CZ science and provide some history and framework for understanding CZ science and CZOs.

In addition to the pre-class readings, students will explore five websites during class:

  1. U.S. Critical Zone Observatory
  2. U.S. National Science Foundation
  3. U.S. National Research Council
  4. Soil Transformations in European Catchments (SoilTrEC) ( This site may be offline. ) and
  5. Critical Zone Exploration Network (CZEN)
Browsing the first website will provide basic information as well as sources of information that students may return to throughout the semester; the SoilTrEC and CZEN Web sites provide the primary portals for linking to international CZ initiatives. The other two websites introduce the federal government organizations that guide and fund such basic research endeavors in the United States.

The students are also asked to begin to consider potential topics for a semester project and to communicate and clear a topic with the instructor by the end of week three of the semester.

Before Class

Pre-class Reading Groups

Throughout this course, we will treat some reading assignments in the following way:

  • The class will be divided into different reading groups
  • Each group will be assigned an article(s) to read.
  • Each group will make a brief (~5 minute) report to the class summarizing their reading assignment.
    • Articles should be reviewed prior to class to capture the main themes and topics discussed and how these relate to this class, module and entire course. As the course proceeds, students will begin to tie concepts learned in earlier lessons to the ongoing lessons and in the process will make the links that are at the heart of this very transdisciplinary science.
    • Research articles should also be reviewed prior to class using the following generic scientific analysis framework and any specific questions provided.
  • Each group will pre-read and meet outside of class to prepare their brief presentation on one of the 4 reports listed below under Pre-class reading articles.
    • focus on concepts of general and broad importance, for example:
      • What do CZOs do?
      • Why is CZ science important? Why are CZOs important?
      • What are the common objectives of CZOs? Place these within the context of the four driving questions:
        • How do variations in and perturbations to chemical and physical weathering processes impact the CZ?
        • How do biogeochemical processes govern long-term sustainability of water and soil resources?
        • How do processes that nourish ecosystems change over human and geologic time scales?
        • What processes control fluxes of carbon, particulates, and reactive gases over different time scales?

Pre-class reading articles:

    1. Committee on Basic Research Opportunities in the Earth Sciences. (2001). The Critical Zone: Earth's Near-surface Environment. In Basic Research Opportunities in Earth Science (pp. 35–45). Washington, D.C.: National Academy Press.
      • Please pay particular attention to Figure 2.1.
    2. Brantley, S., White, T., White, A., Sparks, D., Richter, D., Pregitzer, K., et al. (2006). Frontiers in exploration of the Critical Zone. In Frontiers in exploration of the Critical Zone: Report of a workshop sponsored by the National Science Foundation (NSF) (pp. 1–30). Newark, DE.
      • Please pay particular attention to Figures 4–7, 10, 11 and 13, and Table 1.
    3. Banwart, S., Chorover, J., Gaillardet, J., Sparks, D., White, T., et al. (2013). Sustaining Earth's Critical Zone: Basic Science and Interdisciplinary Solutions for Global Challenges, University of Sheffield, United Kingdom, ISBN: 978-0-9576890-0-8.
    4. NSF Review Panel (2011), Critical Zone Observatory Program, NSF (https://www.nsf.gov/geo/ear/programs/czo-panel-report-april11.doc)

During Class (75 min total)

Part I: Class lecture: Overview of CZO's (15 min)

This unit should begin with a thirty-minute lecture (PowerPoint 2007 (.pptx) 2.8MB Jan31 17) aimed at introducing the students to the highlights of what they will read in their group assignment and individual reading and website browsing (see below, References and Resources). A "retrieval practice" approach to metacognition should be implemented during this lecture by asking frequent relevant exam-style questions, and then gathering the students toward the end of class to revisit those questions (and answers). The goals for the remainder of the lesson should be two-fold:

1) To meet individually with each student to begin to explore potential semester project topics of interest to the student and acceptable to the instructor. The instructor will follow one of two directions as described below under Lesson Plan, which generally link to at least one of the course-level goals as well as address an issue(s) relating to sustainability of Critical Zone resources, environmental (CZ) stability, and/or human quality of life, health and safety. The semester project will develop over the following schedule:

a) clearance of a final topic with the instructor by the end of week 3;

b) a 2-page outline due by the end of week 6;

c) a 2 slides/2 minutes update presentation in week 12; and,

d) a 10-15 minute presentation, and a 10-pages, double-spaced, properly-referenced report of the topic in class during week 15.

2) To browse various websites (listed below) to further the students' understanding of basic science policy and funding in the United States, online resources for studying the Critical Zone, and the international scope of Critical Zone science.

Materials

Part II: Reading Groups will report on reading assignments (30 min)

  • Each group gives a ~5 min summary of their reading. The 30 minutes allotted for this activity are meant to account for groups that go over the 5 minute limit and to provide for the logistics of switching between groups.

Part III: Class lecture: Introduction to Semester Project (15 min)

  • Handout: Link to Project objectives and requirements
    • NSF Request for Proposals (RFP) (Microsoft Word 2007 (.docx) 18kB Apr12 17) - students write a 10-page proposal for a hypothetical NSF RFP
    • Alternative Assignment: Grand Challenge Paper (Microsoft Word 2007 (.docx) 23kB Apr12 17) - students write a 10-page paper and give a 10-15 minute class presentation on a topic of their choosing.
Part IV: In-class web browsing (requires computers/internet) (15 min)

Homework - Pre/Post Critical Zone Science Personal Reflection

(Note: this assignment is listed under Unit 0.1 on the student pages)

Write a one-page statement of four aspects of the Critical Zone:

  • define what it is;
  • explain where it is;
  • describe how it functions; and,
  • why it is important to society.

Include a brief description of student learning goals for the semester to be compared to a similar statement to be written in the final week of the semester---in the latter case, a statement of reflection on what you learned and whether you achieved your goals.

Assessment

Pre/Post Critical Zone Science Personal Reflection

For homework at the end of this unit, the students will write a one-page statement of four aspects of the Critical Zone: define what it is, explain where it is, and describe how it functions and why it is important to society. The student should also briefly describe what the four driving questions mean to them. Finally, the statement should also include a brief description of the student's learning goals for the semester to be compared to a similar statement to be written in the final week of the semester---in the latter case, a statement of reflection on what they learned and whether they achieved their goals. The statement will provide the instructor with baseline information regarding students' knowledge and comprehension of Critical Zone concepts, as well as a mechanism for assessing the students' growth in Critical Zone science knowledge through the semester. The statement also provides the students with a self assessment tool.

A Short Essay Rubric (Microsoft Word 2007 (.docx) 25kB Dec26 16) is provided.

References and Resources

The four reports for group reading are:
  1. Committee on Basic Research Opportunities in the Earth Sciences. (2001). The Critical Zone: Earth's Near-surface Environment. In Basic Research Opportunities in Earth Science (pp. 35–45). Washington, D.C.: National Academy Press.
    • Please pay particular attention to Figure 2.1.
  2. Brantley, S., White, T., White, A., Sparks, D., Richter, D., Pregitzer, K., et al. (2006). Frontiers in exploration of the Critical Zone. In Frontiers in exploration of the Critical Zone: Report of a workshop sponsored by the National Science Foundation (NSF) (pp. 1–30). Newark, DE.
    • Please pay particular attention to Figures 4–7, 10, 11 and 13, and Table 1.
  3. Banwart, S., Chorover, J., Gaillardet, J., Sparks, D., White, T., et al. (2013). Sustaining Earth's Critical Zone: Basic Science and Interdisciplinary Solutions for Global Challenges, University of Sheffield, United Kingdom, ISBN: 978-0-9576890-0-8.
  4. NSF Review Panel (2011), Critical Zone Observatory Program, NSF (https://www.nsf.gov/geo/ear/programs/czo-panel-report-april11.doc)

Individually, students browse the following websites and read the following chapter:

  • U.S. Critical Zone Observatory Website: http://www.criticalzone.org
    • an important website that you will visit and use repeatedly throughout this course.
    • specifically note the 9 existing U.S. CZOs
  • U.S. National Science Foundation Website: http://www.nsf.gov

    • the U.S. federal agency that funds the CZO network; click on "About" and read through this brief introduction to the NSF, following the MORE links for greater detail.
  • U.S. National Research Council Website: http://www.nationalacademies.org/nrc/

    • Learn about how research strategies and policies are developed in the U.S.; browse the section on the Earth and Life Studies Division (DELS), and under DELS, read the "About us" section.
  • Soil Transformations in European Catchments Website: (SoilTrEC); http://www.soiltrec.eu/

    • one-time European equivalent of the U.S. CZO program.
  • Critical Zone Exploration Network Website: http://www.czen.org

    • the "go to" site for international CZ science; read the "About CZEN" section.

  • White T., Brantley S., Banwart S., Chorover J., Dietrich W., Derry L., Lohse K., Anderson S., Aufdendkampe A., Bales R., Kumar P., Richter D., McDowell B. (2015) Chapter 2 – The Role of Critical Zone Observatories in Critical Zone Science, in Developments in Earth Surface Processes 19: 15–78, CZO link
    • Focus on sections 2.1, 2.3 and 2.4; 2.2 gets into too much detail about the individual CZO sites.

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These materials are part of a collection of classroom-tested modules and courses developed by InTeGrate. The materials engage students in understanding the earth system as it intertwines with key societal issues. The collection is freely available and ready to be adapted by undergraduate educators across a range of courses including: general education or majors courses in Earth-focused disciplines such as geoscience or environmental science, social science, engineering, and other sciences, as well as courses for interdisciplinary programs.
Explore the Collection »