Chapter 4
The Democracy of Dirt: Relating
Micro-Scale Dynamics to Macro-Scale
Ecosystem Function
Joshua Schimel
Abstract Soil can be analogized as a “democracy” in which there are three “political parties” (microbes, minerals, and organic molecules) that sometimes compete
and sometimes cooperate in controlling biogeochemical process in the soil system.
These interactions are in turn regulated by the media that regulate the flow of
material and information through the system; in soil the key medium is moisture,
which regulates substrate solubility and transport. Modern soil science is increasingly sophisticated in our tools to analyze these phenomena with high resolution at
fine scales— ‘omics identifies thousands of microbial taxa, tomography maps the
3-D pore structure of a single aggregate, and chromatography-mass spectrometry
systems identify molecules in soil. Yet, we are still challenged to assimilate the
masses of data these methods produce to explain the overall functioning of the soil
system. For example, why do molecules that microbes can metabolize in minutes
still persist for centuries or millennia? How we assimilate these new data into the
models (conceptual and mathematical) that we use to understand and characterize
the soil system is fundamental to developing integrated perspectives on soil and its
roles in biogeochemical cycles. In this chapter, I discuss ideas and approaches for
integrating data to better bridge from the micron-scale processes that occur on
mineral surfaces or in individual soil pores to meter- and kilometer-scale phenomena
within soil profiles and landscapes and which drive the functioning of terrestrial
ecosystems.
4.1 Introduction
Democracy is the worst form of government, except for all those other forms that have been
tried. . .
J. Schimel (*)
Department of Ecology, Evolution, and Marine Biology, University of California, California,
USA
e-mail: schimel@lifesci.ucsb.edu
© Springer Nature Switzerland AG 2021
C. J. Hurst (ed.), Microbes: The Foundation Stone of the Biosphere, Advances in
Environmental Microbiology 8, https://doi.org/10.1007/978-3-030-63512-1_4
89
The Democracy of Dirt: Relating
Micro-Scale Dynamics to Macro-Scale
Ecosystem Function
Joshua Schimel
Abstract Soil can be analogized as a “democracy” in which there are three “political parties” (microbes, minerals, and organic molecules) that sometimes compete
and sometimes cooperate in controlling biogeochemical process in the soil system.
These interactions are in turn regulated by the media that regulate the flow of
material and information through the system; in soil the key medium is moisture,
which regulates substrate solubility and transport. Modern soil science is increasingly sophisticated in our tools to analyze these phenomena with high resolution at
fine scales— ‘omics identifies thousands of microbial taxa, tomography maps the
3-D pore structure of a single aggregate, and chromatography-mass spectrometry
systems identify molecules in soil. Yet, we are still challenged to assimilate the
masses of data these methods produce to explain the overall functioning of the soil
system. For example, why do molecules that microbes can metabolize in minutes
still persist for centuries or millennia? How we assimilate these new data into the
models (conceptual and mathematical) that we use to understand and characterize
the soil system is fundamental to developing integrated perspectives on soil and its
roles in biogeochemical cycles. In this chapter, I discuss ideas and approaches for
integrating data to better bridge from the micron-scale processes that occur on
mineral surfaces or in individual soil pores to meter- and kilometer-scale phenomena
within soil profiles and landscapes and which drive the functioning of terrestrial
ecosystems.
4.1 Introduction
Democracy is the worst form of government, except for all those other forms that have been
tried. . .
J. Schimel (*)
Department of Ecology, Evolution, and Marine Biology, University of California, California,
USA
e-mail: schimel@lifesci.ucsb.edu
© Springer Nature Switzerland AG 2021
C. J. Hurst (ed.), Microbes: The Foundation Stone of the Biosphere, Advances in
Environmental Microbiology 8, https://doi.org/10.1007/978-3-030-63512-1_4
89