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Our Projects
Understanding and accurately predicting the complexities of the terrestrial carbon cycle poses a significant challenge. It requires a deep comprehension of the fundamental mechanisms driving it and the ability to quantify these mechanisms across different scales, ranging from the micro to the global level. The terrestrial carbon cycle primarily unfolds at the soil surface within the vadose zone, where conditions vary spatially and temporally. These conditions result from intricate interactions among physical, chemical, and biological components. Our goal is to shed light on the primary driver of the terrestrial carbon cycle—the water cycle—by uncovering its dynamic coupling with terrestrial carbon fluxes at various scales, from the small to the large.
Phase distribution in natural porous media
Water plays a crucial role in driving biogeochemical cycles within terrestrial ecosystems, exerting influence on vital processes such as nutrient cycling, transport, fluxes, and microbial activity. Employing non-invasive techniques such as micro-CT scanning and microscopy, we aim to gain comprehensive insights into the spatial distribution of water across diverse soil types and environmental conditions. This enables us to establish universal scaling laws for air-water spatial distribution, which are subsequently utilized in biogeochemical modeling efforts.
Interaction between organic matter and microorganisms
Soil microorganisms play a pivotal role in the terrestrial carbon cycle, contributing significantly to the largest carbon dioxide flux to the atmosphere. Their capacity to utilize roots and litterfall as an energy source is instrumental in regulating carbon cycling on land. Employing high-resolution micro-scale observations, we delve into the intricate interactions between organic matter, encompassing roots and particulate organic carbon, at the pore scale. Through this research, our goal is to elucidate the fundamental mechanisms shaping the rhizosphere environment, particularly in response to various environmental conditions.
Terrestrial carbon cycle under changing environmental conditions
One of the paramount challenges of the 21st century is the escalating concentration of carbon dioxide in the atmosphere, driving global warming. To unravel the complex environment governing the carbon cycle and its potential future changes, we use climate chambers in laboratory settings to control environmental conditions, alongside advanced water and carbon sensors. These tools enable us to observe how different water carbon fluxes, such as photosynthesis and respiration, and reservoirs, including organic matter and microorganisms, within terrestrial ecosystems respond to diverse climatic conditions across various ecosystem types.
Fluid flow and (bio-)reactive transport in porous media
Fluid flow and (bio)chemical transport and reactions are integral to numerous environmental and industrial applications, including nutrient transport, remediation of polluted sites, carbon dioxide storage, oil recovery, geothermal energy extraction, and filtration processes. The inherent complexity of natural porous media, coupled with the dynamic nature of environmental conditions, presents significant challenges in characterizing these phenomena. Our research is dedicated to study the interplay between flow dynamics, mixing/transport processes, and reaction kinetics occurring in fluid-fluid, fluid-solid, and biologically-induced reactions within porous and fractured media. We employ various scales of observation and modeling techniques to achieve this goal.
Machine learning approach to assess the terrestrial ecosystem response to climate change
We employ machine learning approaches to estimate the terrestrial carbon (for now) cycle on a global scale. Utilizing diverse sources of data, including flux tower data, remote sensing imagery, soil proporties, mineralogy, and microbial databases. Our objective is to establish a simple and cost-effective method to assess the terrestrial carbon cycle and to predict future alterations at a global scale.
Feel free to reach out to me if you have any questions...
Contact email: alon.nissan@mail.huji.ac.il
The Department of Soil and Water Sciences, The Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem
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