Influence of carbon and nitrogen on cellulose and lignin degradation in forest soils

1995 ◽  
Vol 25 (8) ◽  
pp. 1231-1236 ◽  
Author(s):  
James A. Entry ◽  
Carole B. Backman
Keyword(s):  
Organic Matter ◽  
Soil Type ◽  
Fungal Biomass ◽  
Lignin Degradation ◽  
Cellulose Degradation ◽  
Bacterial Biomass ◽  
Terrestrial Ecosystems ◽  
Organic Matter Decomposition ◽  
Decomposition Rates ◽  
C And N

The concentration of lignin in plant tissue is a major factor controlling organic matter decomposition rates in terrestrial ecosystems. Microcosms were used to determine the influence of C and N additions on active bacterial and active fungal biomass, cellulose degradation, and lignin degradation at 4, 8, and 12 weeks in soils from the Tuskeege National Forest in southern Alabama. Active bacterial and active fungal biomass was determined by direct microscopy; cellulose and lignin degradation were measured radiometrically. The experimental design was a 33 latin square. Treatments were as follows: soil type, soil C (soils amended with the equivalent of 0, 400, or 800 kg C•ha−1 as cellulose), and soil N (soils amended with the equivalent of 0, 250, or 500 kg N•ha−1 as NH4NO3). Active bacterial biomass, active fungal biomass, and cellulose and lignin degradation did not differ with soil type. Active bacterial biomass was not affected by N or C additions. As C and N concentrations increased, active fungal biomass as well as cellulose and lignin degradation increased. The concentration of C and N (together) in the soil correlated with both cellulose and lignin degradation (r2 = 0.76, p < 0.001; r2 = 0.44, p < 0.001, respectively). Active fungal biomass correlated curvilinearly with both cellulose and lignin degradation (r2 = 0.38, p < 0.001; r2 = 0.33, p < 0.001, respectively). The lignin:N ratio is often used to predict organic matter decomposition rates in terrestrial ecosystems. These results lead us to conclude that a cellulose:lignin:N ratio may be a more accurate predictor of organic matter decomposition rates than C:N ratio or lignin:N ratios.

scholarly journals Linking Genes to Traits in Fungi

2021 ◽  
Author(s):  
A. L. Romero-Olivares ◽  
E. W. Morrison ◽  
A. Pringle ◽  
S. D. Frey
Keyword(s):  
Organic Matter ◽  
Nitrogen Uptake ◽  
Brown Rot ◽  
Terrestrial Ecosystems ◽  
Organic Matter Decomposition ◽  
Gene Frequencies ◽  
Ecological Processes ◽  
Linked Gene ◽  
Carbon Cycles ◽  
Brown Rot Fungi

AbstractFungi are mediators of the nitrogen and carbon cycles in terrestrial ecosystems. Examining how nitrogen uptake and organic matter decomposition potential differs in fungi can provide insight into the underlying mechanisms driving fungal ecological processes and ecosystem functioning. In this study, we assessed the frequency of genes encoding for specific enzymes that facilitate nitrogen uptake and organic matter decomposition in 879 fungal genomes with fungal taxa grouped into trait-based categories. Our linked gene-trait data approach revealed that gene frequencies vary across and within trait-based groups and that trait-based categories differ in trait space. We present two examples of how this linked gene-trait approach can be used to address ecological questions. First, we show that this type of approach can help us better understand, and potentially predict, how fungi will respond to environmental stress. Specifically, we found that trait-based categories with high nitrogen uptake gene frequency increased in relative abundance when exposed to high soil nitrogen enrichment. Second, by comparing frequencies of nitrogen uptake and organic matter decomposition genes, we found that most ectomycorrhizal fungi in our dataset have similar gene frequencies to brown rot fungi. This demonstrates that gene-trait data approaches can shed light on potential evolutionary trajectories of life history traits in fungi. We present a framework for exploring nitrogen uptake and organic matter decomposition gene frequencies in fungal trait-based groups and provide two concise examples on how to use our framework to address ecological questions from a mechanistic perspective.

scholarly journals Sediment community responses to marine vs. terrigenous organic matter in a submarine canyon

2013 ◽  
Vol 10 (1) ◽  
pp. 67-80 ◽  
Author(s):  
W. R. Hunter ◽  
A. Jamieson ◽  
V. A. I. Huvenne ◽  
U. Witte
Keyword(s):  
Organic Matter ◽  
Feeding Activity ◽  
N Uptake ◽  
Bacterial Biomass ◽  
Submarine Canyon ◽  
Stable Isotope Labelling ◽  
C And N ◽  
13C Label ◽  
Experimental Treatments

Abstract. The Whittard Canyon is a branching submarine canyon on the Celtic continental margin, which may act as a conduit for sediment and organic matter (OM) transport from the European continental slope to the abyssal sea floor. In situ stable-isotope labelling experiments were conducted in the eastern and western branches of the Whittard Canyon, testing short-term (3–7 days) responses of sediment communities to deposition of nitrogen-rich marine (Thalassiosira weissflogii) and nitrogen-poor terrigenous (Triticum aestivum) phytodetritus. 13C and 15N labels were traced into faunal biomass and bulk sediments, and the 13C label traced into bacterial polar lipid fatty acids (PLFAs). Isotopic labels penetrated to 5 cm sediment depth, with no differences between stations or experimental treatments (substrate or time). Macrofaunal assemblage structure differed between the eastern and western canyon branches. Following deposition of marine phytodetritus, no changes in macrofaunal feeding activity were observed between the eastern and western branches, with little change between 3 and 7 days. Macrofaunal C and N uptake was substantially lower following deposition of terrigenous phytodetritus with feeding activity governed by a strong N demand. Bacterial C uptake was greatest in the western branch of the Whittard Canyon, but feeding activity decreased between 3 and 7 days. Bacterial processing of marine and terrigenous OM were similar to the macrofauna in surficial (0–1 cm) sediments. However, in deeper sediments bacteria utilised greater proportions of terrigenous OM. Bacterial biomass decreased following phytodetritus deposition and was negatively correlated to macrofaunal feeding activity. Consequently, this study suggests that macrofaunal–bacterial interactions influence benthic C cycling in the Whittard Canyon, resulting in differential fates for marine and terrigenous OM.

scholarly journals Compositional and chemical characteristics of dissolved organic matter in various types of cropped and natural Chinese soils

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Songyan Li ◽  
Meng Li ◽  
Guoxi Wang ◽  
Xiaolei Sun ◽  
Beidou Xi ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Soil Type ◽  
Spectral Characteristics ◽  
Terrestrial Ecosystems ◽  
Soil Types ◽  
Chemical Characteristics ◽  
Natural Soils ◽  
Red Soils ◽  
Chernozem Soils

Abstract Background Exploration of composition and chemical characteristics of soil dissolved organic matter (DOM) is significant to understand its biogeochemical role in terrestrial ecosystems. A total of 43 cropped and 16 natural soils (0–20 cm) under four soil types (cinnamon, chernozem, red and paddy soils) across China were collected to investigate the spectral characteristics of DOM using UV–Vis and 3D-EEM spectroscopy. Results The chernozem soils exhibited the highest aromaticity and humification degree among the four soil types. Ranges of biological index (BIX, 0.53–1.17) and fluorescence index (FI, 1.55–2.10) were found in the investigated DOM, showing joint contribution from allochthonous and autochthonous sources. Higher BIX and FI in the DOM of the paddy and red soils indicated a greater reliance on autochthonous sources for these two soil types. The cropped soils showed no significant differences in chemical characteristics and sources from the natural soils for the cinnamon, chernozem and red soils. UVA (16.2–47.9%) and UVC fulvic-like substances (15.4–40.5%) were the prevailing DOM components, which were highest in the chernozem soils. Additionally, the cropped soils had a higher proportion of humic-like substances than the natural soils in the DOM. Conclusions Both soil type and land-use strongly affected the chemical characteristics of soil DOM, but only soil type had an impact on the DOM composition for the collected soils. These findings may contribute to the prediction of the biochemical behavior of soil DOM under different soil types and land-uses in terrestrial ecosystems.

Mountain lakes increase organic matter decomposition rates in streams

2010 ◽  
Vol 29 (2) ◽  
pp. 521-529 ◽  
Author(s):  
Keli J. Goodman ◽  
Michelle A. Baker ◽  
Wayne A. Wurtsbaugh
Keyword(s):  
Organic Matter ◽  
Mountain Lakes ◽  
Organic Matter Decomposition ◽  
Decomposition Rates

Temperature sensitivity of soil organic matter decomposition varies with biochar application and soil type

Pedosphere ◽  
2020 ◽  
Vol 30 (3) ◽  
pp. 336-342
Author(s):  
Tatiana F. RITTL ◽  
Luiza CANISARES ◽  
Edvaldo SAGRILO ◽  
Klaus BUTTERBACH-BAHL ◽  
Michael DANNENMANN ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Temperature Sensitivity ◽  
Soil Type ◽  
Organic Matter Decomposition ◽  
Soil Organic Matter Decomposition

scholarly journals Sensitivity analysis of six soil organic matter models applied to the decomposition of animal manures and crop residues

2016 ◽  
Vol 11 ◽  
Author(s):  
Daniele Cavalli ◽  
Pietro Marino Gallina ◽  
Luca Bechini
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Organic Matter Decomposition ◽  
Model Parameters ◽  
Monod Kinetics ◽  
Decomposition Rates ◽  
Mineral N ◽  
First Order ◽  
Inhibition Hypothesis ◽  
C Decomposition

Two features distinguishing soil organic matter simulation models are the type of kinetics used to calculate pool decomposition rates, and the algorithm used to handle the effects of N shortage on C decomposition. Compared to widely used first-order kinetics, Monod kinetics more realistically represent organic matter decomposition, because they relate decomposition to both substrate and decomposer size. Most models impose a fixed C to N ratio for microbial biomass. When N required by microbial biomass to decompose a given amount of substrate- C is larger than soil available N, carbon decomposition rates are limited proportionally to N deficit (N inhibition hypothesis). Alternatively, C-overflow was proposed as a way of getting rid of excess C, by allocating it to a storage pool of polysaccharides. We built six models to compare the combinations of three decomposition kinetics (first-order, Monod, and reverse Monod), and two ways to simulate the effect of N shortage on C decomposition (N inhibition and C-overflow). We conducted sensitivity analysis to identify model parameters that mostly affected CO<sub>2</sub> emissions and soil mineral N during a simulated 189-day laboratory incubation assuming constant water content and temperature. We evaluated model outputs sensitivity at different stages of organic matter decomposition in a soil amended with three inputs of increasing C to N ratio: liquid manure, solid manure, and low-N crop residue. Only few model parameters and their interactions were responsible for consistent variations of CO<sub>2</sub> and soil mineral N. These parameters were mostly related to microbial biomass and to the partitioning of applied C among input pools, as well as their decomposition constants. In addition, in models with Monod kinetics, CO<sub>2</sub> was also sensitive to a variation of the halfsaturation constants. C-overflow enhanced pool decomposition compared to N inhibition hypothesis when N shortage occurred. Accumulated C in the polysaccharides pool decomposed slowly; therefore model outputs were not sensitive to a variation of its decay constant. Six-month organic matter decomposition was generally higher for models implementing classical Monod kinetics, followed by models with first-order and reverse Monod kinetics, due to the effect of soil microbial biomass growth on decomposition rates. Moreover, models implementing Monod kinetics predicted positive priming effects of native organic matter after soil amendment, according to co-metabolism theory. Thus, priming was proportional to the increase of the microbial biomass and in turn to the decomposability of applied organic matter. We conclude that model calibration should focus only on the few important parameters.

scholarly journals Models of soil organic matter decomposition: the SOILR package, version 1.0

2012 ◽  
Vol 5 (2) ◽  
pp. 993-1039 ◽  
Author(s):  
C. A. Sierra ◽  
M. Müller ◽  
S. E. Trumbore
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Matter Decomposition ◽  
Important Process ◽  
Decomposition Rates ◽  
Modeling Framework ◽  
Soil Organic Matter Decomposition ◽  
The Earth ◽  
Decomposition Models ◽  
Model Structures

Abstract. Organic matter decomposition is a very important process within the Earth System because it controls the rates of mineralization of carbon and other biogeochemical elements, determining their flux to the atmosphere and the hydrosphere. SOILR is a modeling framework that contains a library of functions and tools for modeling soil organic matter decomposition under the R environment for computing. It implements a variety of model structures and tools to represent carbon storage and release from soil organic matter. In SOILR organic matter decomposition is represented as a linear system of ordinary differential equations that generalizes the structure of most compartment-based decomposition models. A variety of functions is also available to represent environmental effects on decomposition rates. This document presents the conceptual basis for the functions implemented in the package. It is complementary to the help pages released with the software.

scholarly journals Reproducible determination of dissolved organic matter photosensitivity

2020 ◽  
Author(s):  
Alec W. Armstrong ◽  
Leanne Powers ◽  
Michael Gonsior
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Terrestrial Ecosystems ◽  
Freshwater Wetlands ◽  
Experimental Conditions ◽  
Time Resolved ◽  
Precise Control ◽  
C And N ◽  
Aquatic Food ◽  
Dom Composition

Abstract. Dissolved organic matter (DOM) connects aquatic and terrestrial ecosystems, plays an important role in C and N cycles, and supports aquatic food webs. Understanding DOM chemical composition and reactivity is key to predict its ecological role, but characterization is difficult as natural DOM is comprised of a large but unknown number of distinct molecules. Photochemistry is one of the environmental processes responsible for changing the molecular composition of DOM and DOM composition also defines its susceptibility to photochemical alteration. Reliably differentiating the photosensitivity of DOM from different sources can improve our knowledge of how DOM composition is shaped by photochemical alteration and aid research into photochemistry's role in various DOM transformation processes. Here we describe an approach to measure and compare DOM photosensitivity consistently based on the kinetics of changes in DOM fluorescence during 20h photodegradation experiments. We assess the influence of experimental conditions that might affect reproducibility, discuss our modelling approach, offer guidelines for adopting our methods, and illustrate possible applications for ecological inferences. Central to our approach is the use of a reference material, precise control of conditions, leveraging actinometry to estimate photon dose, and frequent (every 20 minutes) fluorescence and absorbance measurements during exposure to artificial sunlight. We compared DOM from freshwater wetlands, a stream, an estuary, and Sargassum sp. leachate and observed differences in sensitivity that could help identify or explain differences in their composition. Finally, we offer an example applying our approach to compare DOM photosensitivity in two adjacent wetlands as seasonal hydrologic changes alter their DOM sources. Our approach may improve reproducibility when compared to other methods and captures time-resolved changes in optical properties that may have been missed previously.

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