Designing a network of critical zone observatories to explore the living skin of the terrestrial Earth

Brantley, SL

McDowell, WH

Dietrich, WE

White, TS

Kumar, P

Anderson, SP

Chorover, J

Ann Lohse, K

Bales, RC

Richter, DD

Grant, G

Gaillardet, J

2020-08-01T15:51:59Z

2020-08-01T15:51:59Z

2017-12-18

2020-08-01T15:51:51Z

The critical zone (CZ), the dynamic living skin of the Earth, extends from the top of the vegetative canopy through the soil and down to fresh bedrock and the bottom of the groundwater. All humans live in and depend on the CZ. This zone has three co-evolving surfaces: the top of the vegetative canopy, the ground surface, and a deep subsurface below which Earth's materials are unweathered. The network of nine CZ observatories supported by the US National Science Foundation has made advances in three broad areas of CZ research relating to the co-evolving surfaces. First, monitoring has revealed how natural and anthropogenic inputs at the vegetation canopy and ground surface cause subsurface responses in water, regolith structure, minerals, and biotic activity to considerable depths. This response, in turn, impacts aboveground biota and climate. Second, drilling and geophysical imaging now reveal how the deep subsurface of the CZ varies across landscapes, which in turn influences aboveground ecosystems. Third, several new mechanistic models now provide quantitative predictions of the spatial structure of the subsurface of the CZ.
Many countries fund critical zone observatories (CZOs) to measure the fluxes of solutes, water, energy, gases, and sediments in the CZ and some relate these observations to the histories of those fluxes recorded in landforms, biota, soils, sediments, and rocks. Each US observatory has succeeded in (i) synthesizing research across disciplines into convergent approaches; (ii) providing long-term measurements to compare across sites; (iii) testing and developing models; (iv) collecting and measuring baseline data for comparison to catastrophic events; (v) stimulating new process-based hypotheses; (vi) catalyzing development of new techniques and instrumentation; (vii) informing the public about the CZ; (viii) mentoring students and teaching about emerging multidisciplinary CZ science; and (ix) discovering new insights about the CZ. Many of these activities can only be accomplished with observatories. Here we review the CZO enterprise in the United States and identify how such observatories could operate in the future as a network designed to generate critical scientific insights. Specifically, we recognize the need for the network to study network-level questions, expand the environments under investigation, accommodate both hypothesis testing and monitoring, and involve more stakeholders. We propose a driving question for future CZ science and a hubs-and-campaigns model to address that question and target the CZ as one unit. Only with such integrative efforts will we learn to steward the life-sustaining critical zone now and into the future.

2196-6311

2196-632X

https://hdl.handle.net/10161/21237

en

Copernicus GmbH

Earth Surface Dynamics

10.5194/esurf-5-841-2017

Science & Technology

Physical Sciences

Geography, Physical

Geosciences, Multidisciplinary

Physical Geography

Geology

INTENSIVELY MANAGED LANDSCAPES

COLORADO FRONT RANGE

SOIL PROCESSES

CLIMATE-CHANGE

NEW-MEXICO

FOREST

WATER

VARIABILITY

CATCHMENT

EVOLUTION

Designing a network of critical zone observatories to explore the living skin of the terrestrial Earth

Journal article

841

860

4

Nicholas School of the Environment

Environmental Sciences and Policy

Duke

Published

5