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Dr. Shikma Zaarur

Rock to soil

 

 

My research focuses on the geochemical processes of rock weathering and soil formation; geochemical dynamics and geobiochemical cycles in the critical zone on macro and micro scales. My work includes field and laboratory-based research combining a wide range of advanced geochemical and analytical methods.
 

What is the ‘Critical Zone’?

critical zone
After Chorover et al, 2007. Catalina-Jemez CZO.

 

While reaching only up to tens of meters at most and negligible in most schematic cross sections of Earth, the ‘critical zone’, which spans from the vegetation canopy to the bedrock or aquifer bottom, sustains most terrestrial life on Earth. The most studied of the critical zone sub-layers is the soils. The balances between inputs and outputs to this layer, make this a dynamic system by definition and the nature of this dynamic relationship determines the ability of the soils to support ecosystems and sustain life.

The critical zone develops from chemical weathering and biological activity that breaks down bedrock and forms soils. This weathering process is a major player in in the global carbon cycle and thus, aside from its agricultural, ecological and economic values, the formation and development of the critical zone play a fundamental role in global chemical and climate cycles.

 

 

 

Why is this important?

My motivation for research comes from the fundamental curiosity to understand the natural processes that shape Earth and its surface. My passion for critical zone and soil geochemistry arises from the recognition of this important layer in our everyday lives. It is well accepted that due to anthropogenic interference, soil erosion exceeds soil production, resulting in massive soil loss on both local and global scales; this is a non-renewable resource, on the time scale of human life. I believe we have an obligation to study and understand soil dynamics and nutrient cycling, so we can better manage this invaluable resource. This understanding must be based on quantifying the natural processes of soil dynamics and a detailed understanding of the processes involved.

 

Why geochemistry?

The main (but not only) tools I use in my research are geochemical. Different geological (and geobiochemical) processes, produce different rocks and minerals with different chemical and isotopic compositions. This results in unique geochemical fingerprints that allows us to trace and study the underlying processes at play. Geochemistry, in a way, is like a language that allows us to “read” the story of Earth’s history and ongoing processes.

rock cycle