Debjani Sihi

Debjani Sihi
Emory University | EU · Department of Environmental Sciences

PhD, University of Florida

About

52
Publications
11,588
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
508
Citations
Additional affiliations
January 2018 - August 2020
Oak Ridge National Laboratory
Position
  • PostDoc Position
August 2015 - December 2017
University of Maryland Center for Environmental Science
Position
  • PostDoc Position
August 2011 - July 2015
University of Florida
Position
  • Research Assistant

Publications

Publications (52)
Article
Full-text available
Recent developments in modelling soil organic carbon decomposition include the explicit incorporation of enzyme and microbial dynamics. A characteristic of these models is a positive feedback between substrate and consumers which is absent in traditional first order decay models. Under sufficient large substrate, this new feedback allows an unconst...
Article
Full-text available
Estimates of gaseous carbon (C) fluxes in wetlands are heavily based on temperature. However, isolating specific effects of temperature on anaerobic C processing from other controls (C quality and nutrients) has proven difficult. Here, we test the hypothesis that temperature sensitivity of soil organic matter (SOM) decomposition is more influenced...
Article
Full-text available
Temperature sensitivity of anaerobic carbon mineralization in wetlands remains poorly represented in most climate models and is especially unconstrained for warmer subtropical and tropical systems which account for a large proportion of global methane emissions. Several studies of experimental warming have documented thermal acclimation of soil res...
Article
Heterotrophic respiration (Rh), microbial processing of soil organic matter to carbon dioxide (CO2), is a major, yet highly uncertain, carbon (C) flux from terrestrial systems to the atmosphere. Temperature sensitivity of Rh is often represented with a simple Q10 function in ecosystem models and earth system models (ESMs), sometimes accompanied by...
Article
Recent developments of enzyme-based decomposition models highlight the importance of enzyme kinetics with warming, but most modeling exercises are based on studies with a step-wise warming. This approach may mask the effect of temperature in controlling in-situ activities as in most ecosystems the rate of warming is more gradual than these step war...
Article
Full-text available
Preventing degradation, facilitating restoration, and maintaining soil health is fundamental for achieving ecosystem stability and resilience. A healthy soil ecosystem is supported by favorable components in the soil that promote biological productivity and provide ecosystem services. Bio-indicators of soil health are measurable properties that def...
Article
Full-text available
Ammonium polyphosphate (APP) is currently being increasingly used as source of phosphorus (P) fertilizer worldwide and has exhibited positive effects on soil P availability in calcareous soils. However, the mechanisms of APP-induced abiotic and biotic transformations of soil P remain elusive. Influences of APP application on P transformation in a c...
Article
Full-text available
Soil nitrous oxide (N2O) emissions are an important driver of climate change and are a major mechanism of labile nitrogen (N) loss from terrestrial ecosystems. Evidence increasingly suggests that locations on the landscape that experience biogeochemical fluxes disproportionate to the surrounding matrix (hot spots) and time periods that show disprop...
Article
Full-text available
A comprehensive understanding of the long-term data on the crop, soils, environment, climate, and production management would facilitate efficient data-driven decision-making in agriculture production under changing climate. We have employed an explainable machine learning algorithm (random forest model coupled with LIME; Local Interpretable Model-...
Article
Full-text available
It is a critical time to reflect on the National Ecological Observatory Network (NEON) science to date as well as envision what research can be done right now with NEON (and other) data and what training is needed to enable a diverse user community. NEON became fully operational in May 2019 and has pivoted from planning and construction to operatio...
Article
Full-text available
Per-and polyfluoroalkyl substances (PFAS) are highly persistent synthetic organic contaminants that can cause serious human health concerns such as obesity, liver damage, kidney cancer, hypertension, immunotoxicity and other human health issues. Integrated crop-livestock systems combine agricultural crop production with milk and/or meat production...
Article
Full-text available
A reanalysis is a physically consistent set of optimally merged simulated model states and historical observational data, using data assimilation. High computational costs for modelled processes and assimilation algorithms has led to Earth system specific reanalysis products for the atmosphere, the ocean and the land separately. Recent developments...
Article
Full-text available
A long‐standing goal of ecology has been to understand the cycling of carbon in forests. This has taken on new urgency with the need to address a rapidly changing climate. Forests serve as long‐term stores for atmospheric CO2, but their continued ability to take up new carbon is dependent on future changes in climate and other factors such as age....
Article
Full-text available
In this study, an inexpensive Nix Pro (Nix Sensor Ltd.) color sensor was used to develop prediction models for soil iron (Fe) content. Thirty‐eight soil samples were collected from five agricultural fields across the Animas watershed to develop and validate soil Fe prediction models. We used color space models to develop three different parameter s...
Article
Full-text available
EPA) regional screening levels (RSL). Total concentrations of 6 out of 7 metals were below the RSL; only As exceeded the soil screening value of 7.07 mg kg −1 at some locations in the agricultural fields. We also determined water-soluble (WS) and exchangeable fractions (Ex) of As that might be available for agricultural crop uptake using sequential...
Article
Full-text available
A growing world population and increases in food and energy consumption have placed production agriculture in a difficult situation. The rapid growth in food production through specialized operations such as monoculture cropping systems has aligned to satisfy increases in demand for food and fiber. However, its adverse impacts on natural resources...
Article
Full-text available
Extractant for estimating plant-available arsenic (As) in soil has not been universally established. Moreover, to assess and monitor the complex chemical behavior of arsenic (As) in soil and subsequently, its transfer in crops, a suitable extraction protocol considering the soil properties in relation to crop uptake is required. For this purpose, a...
Article
Full-text available
Tropical ecosystems contribute significantly to global emissions of methane (CH4), and landscape topography influences the rate of CH4 emissions from wet tropical forest soils. However, extreme events such as drought can alter normal topographic patterns of emissions. Here we explain the dynamics of CH4 emissions during normal and drought condition...
Article
Full-text available
Disturbances fundamentally alter ecosystem functions, yet predicting their impacts remains a key scientific challenge. While the study of disturbances is ubiquitous across many ecological disciplines, there is no agreed-upon, cross-disciplinary foundation for discussing or quantifying the complexity of disturbances, and no consistent terminology or...
Article
Full-text available
Understanding seasonal and diurnal dynamics of ecosystem respiration (Reco) in forests is challenging, because Reco can only be measured directly during night‐time by eddy‐covariance flux towers. Reco is the sum of soil respiration (Rsoil) and above‐ground respiration (in theory, RAG = Reco − Rsoil). Rsoil can be measured day and night and can prov...
Article
Full-text available
Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil-toatmosphere CO2 flux, commonly though imprecisely termed soil respiration (RS), is one of the largest car...
Article
Full-text available
Measuring the soil‐to‐atmosphere carbon dioxide (CO2) flux (soil respiration, RS) is important to understanding terrestrial carbon balance and to forecasting climate change. Such measurements are frequently made using measurement collars permanently inserted into the soil surface. However, differences in measurement duration and frequency, as well...
Article
Full-text available
Scientists leverage long-term environmental measurements, emerging satellite observations, and recent modeling advances to examine changes in ecosystem carbon and water cycling.
Preprint
Full-text available
Tropical ecosystems contribute significantly to global emissions of methane (CH4) and landscape topography influences the rate of CH4 emissions from wet tropical forest soils. However, extreme events such as drought can alter normal topographic patterns of emissions. Here we explain the dynamics of CH4 emissions during normal and drought conditions...
Article
Full-text available
Optimizing barley (hordeum vulgare L.) production in Idaho and other parts of the Pacific Northwest (PNW) should focus on farm resource management. The effect of post-harvest residue management on barley residue decomposition has not been adequately studied. Thus, the objective of this study was to determine the effect of residue placement (surface...
Article
Full-text available
Water contamination is often reported in agriculturally intensive areas such as the Indo-Gangetic Plain (IGP) in southeastern Asia. We evaluated the impact of the organic and conventional farming of basmati rice on water quality during the rainy season (July to October) of 2011 and 2016 at Kaithal, Haryana, India. The study area comprised seven org...
Article
Full-text available
Water contamination is often reported in agriculturally intensive areas such as the Indo-Gangetic Plain (IGP) in southeastern Asia. We evaluated the impact of the organic and conventional farming of basmati rice on water quality during the rainy season (July to October) of 2011 and 2016 at Kaithal, Haryana, India. The study area comprised seven org...
Preprint
Disturbances fundamentally alter ecosystem functions; yet predicting the impacts of disturbances remains a key scientific challenge. The study of disturbances is ubiquitous across almost all ecological disciplines, yet varying terminology and methodologies have led to the lack of an agreed upon, cross-disciplinary foundation for discussing and quan...
Chapter
Depending upon type and pedogenic stage, soils are subject to biotic and abiotic interactions of complex nature depending on type, nature and specific properties. Soil biogeochemistry involves the study of elemental cycling as mediated by complex and inseparable interactions between the biotic (living) and abiotic (non-living) components of soils....
Chapter
Heavy metals are among the main pollutants affecting plant photosynthesis. A broad literature screening reveals that heavy metals impair, in a type‐ and dose‐dependent manner, many aspects related to the photosynthetic apparatus. This chapter explores how stomatal and mesophyll conductances, chloroplasts, photosynthetic pigments, photosystems I and...
Article
Production and consumption of nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) are affected by complex interactions of temperature, moisture, and substrate supply, which are further complicated by spatial heterogeneity of the soil matrix. This microsite heterogeneity is often invoked to explain non-normal distributions of greenhouse gas...
Article
Full-text available
Soil organic matter (SOM) is central to soil carbon (C) storage and terrestrial nutrient cycling. New data have upended the traditional model of stabilization, which held that stable SOM was mostly made of undecomposed plant molecules. We now know that microbial by-products and dead cells comprise unexpectedly large amounts of stable SOM because th...
Article
Full-text available
Soil organic matter (SOM) is a critical ecosystem variable regulated by interacting physical, chemical and biological processes. Collaborative efforts to integrate perspectives, data, and models from interdisciplinary research and observation networks can significantly advance predictive understanding of SOM. We outline how integrating three networ...
Article
Root Trait and Soil Carbon Workshop; Oak Ridge National Laboratory, Oak Ridge, Tennessee, 31 July to 1 August 2018
Chapter
Rice (Oryza sativa L.) is the second largest cereal crop produced globally, with a worldwide production of about 720 million metric tons in recent years and contributing toward for 20% of the global calorie intake. The growing condition of rice is extreme such as high vs. low temperature and high vs. low level of CO2 concentration [CO2]. Given CO2...
Article
Management of phosphorus (P) loss in soils with heavy manure application requires improved understanding of the transformation characteristics of soil P. Influences of manure application on the forms and sorption-desorption characteristics of P in surface (0–30 cm) and subsurface (30–60 cm) layer of a calcareous soil were investigated in a six-year...
Article
Conventional agricultural practices that use excessive chemical fertilizers and pesticides come at a great price with respect to soil health, a key component to achieve agricultural sustainability. Organic farming could serve as an alternative agricultural system and solve the problems associated with the usage of agro-chemicals by sustainable use...
Article
Rice (Oryza sativa L.) is the most important staple food crop in the southern region of Asia, and Indian subcontinent being one of the major producers. Production of conventional transplanted rice requires a large amount of irrigation water, labor, and energy. The scarcity of irrigation water has encouraged farmers to adopt an alternative rice prod...
Article
Rice (Oryza sativa L.) is the most important staple food crop in the southern region of Asia, and Indian subcontinent being one of the major producers. Production of conventional transplanted rice requires a large amount of irrigation water, labor, and energy. The scarcity of irrigation water has encouraged farmers to adopt an alternative rice prod...
Article
Rice (Oryza sativa L.) is the most important staple food crop in the southern region of Asia, and Indian subcontinent being one of the major producers. Production of conventional transplanted rice requires a large amount of irrigation water, labor, and energy. The scarcity of irrigation water has encouraged farmers to adopt an alternative rice prod...
Conference Paper
Soil fluxes of methane (CH4) are often sensitive to soil water content, and the same soil profile may alternate between being a net source or a net sink for CH4 depending on the concentration of oxygen (O2) at microbial microsites. The dynamics of soil moisture and O2 are likely to play a pivotal role in biotic feedbacks to climate change, but it r...
Conference Paper
Extracellular enzymes are the proximate agents for organic matter degradation, but the turnover rate of enzymes is often assumed in most decomposition models without direct observations. Here, we assess turnover rates of C (ß-D-glucosidase), N (Leucine aminopeptidase), and P (Phosphomonoesterase) degrading enzymes by spiking commercially available...
Conference Paper
Recent developments of enzyme-based decomposition models highlight the importance of enzyme kinetics with warming, but most modeling exercises are based on studies with a step-wise warming. This approach may mask the effect of temperature in controlling in-situ activities as in most ecosystems soil temperature change more gradually than air tempera...
Conference Paper
Net uptake of atmospheric nitrous oxide (N2O) has been observed sporadically for many years. Such observations have often been discounted as measurement error or noise, but they were reported frequently enough to gain some acceptance as valid. The advent of fast response field instruments with good sensitivity and precision has permitted confirmati...
Article
Full-text available
Recent developments in modelling soil organic carbon decomposition include the explicit incorporation of enzyme and microbial dynamics. A characteristic of these models is a positive feedback between substrate and consumers which is absent in traditional first order decay models. Under sufficient large substrate, this new feedback allows an unconst...
Conference Paper
Temperature sensitivity of anaerobic carbon processing in wetlands remains poorly represented in most climate models, especially for warmer systems which account for a significant proportion of global CH4 emission. Several studies of experimental warming have documented acclimation of soil respiration involving adjustments in microbial physiology o...
Technical Report
Final report. St. Johns River Water Management District, Palatka, FL
Conference Paper
Anaerobic carbon (C) processing in warmer peatlands is relatively unexplored compared to northern systems. Temperature has a dominant influence on CO2 and CH4 fluxes in northern wetlands. However, specific effects of temperature on C mineralization in warmer wetlands remain difficult to isolate from other factors such as C quality and nutrients. Ou...

Network

Cited By

Projects

Project (1)
Project
Details on this project can be found here: http://research.al.umces.edu/~davidson/index.php/research-projects/integrated-belowground-greenhouse-gas-flux-measurements-and-modeling/