scholarly journals Benthic Bacterial and Fungal Productivity and Carbon Turnover in a Freshwater Marsh

2006 ◽  
Vol 72 (1) ◽  
pp. 596-605 ◽  
Author(s):  
Nanna Buesing ◽  
Mark O. Gessner
Keyword(s):  
Heterotrophic Bacteria ◽  
Plant Litter ◽  
Microbial Production ◽  
Freshwater Marsh ◽  
Sediment Layer ◽  
Submerged Plant ◽  
Production Rates ◽  
Carbon Demand ◽  
Microbial Carbon ◽  
Bacteria And Fungi

ABSTRACT Heterotrophic bacteria and fungi are widely recognized as crucial mediators of carbon, nutrient, and energy flow in ecosystems, yet information on their total annual production in benthic habitats is lacking. To assess the significance of annual microbial production in a structurally complex system, we measured production rates of bacteria and fungi over an annual cycle in four aerobic habitats of a littoral freshwater marsh. Production rates of fungi in plant litter were substantial (0.2 to 2.4 mg C g−1 C) but were clearly outweighed by those of bacteria (2.6 to 18.8 mg C g−1 C) throughout the year. This indicates that bacteria represent the most actively growing microorganisms on marsh plant litter in submerged conditions, a finding that contrasts strikingly with results from both standing dead shoots of marsh plants and submerged plant litter decaying in streams. Concomitant measurements of microbial respiration (1.5 to 15.3 mg C-CO2 g−1 of plant litter C day−1) point to high microbial growth efficiencies on the plant litter, averaging 45.5%. The submerged plant litter layer together with the thin aerobic sediment layer underneath (average depth of 5 mm) contributed the bulk of microbial production per square meter of marsh surface (99%), whereas bacterial production in the marsh water column and epiphytic biofilms was negligible. The magnitude of the combined production in these compartments (∼1,490 g C m−2 year−1) highlights the importance of carbon flows through microbial biomass, to the extent that even massive primary productivity of the marsh plants (603 g C m−2 year−1) and subsidiary carbon sources (∼330 g C m−2 year−1) were insufficient to meet the microbial carbon demand. These findings suggest that littoral freshwater marshes are genuine hot spots of aerobic microbial carbon transformations, which may act as net organic carbon importers from adjacent systems and, in turn, emit large amounts of CO2 (here, ∼870 g C m−2 year−1) into the atmosphere.

scholarly journals Transcription of protease and chitinase genes provides a window onto macromolecular organic nitrogen decomposition in soil

2020 ◽  
Author(s):  
Ella T. Sieradzki ◽  
Erin E. Nuccio ◽  
Jennifer Pett-Ridge ◽  
Mary K. Firestone
Keyword(s):  
Soil Bacteria ◽  
Extracellular Enzymes ◽  
Plant Litter ◽  
Organic Substrates ◽  
Extracellular Proteases ◽  
Carbon And Nitrogen ◽  
Limiting Nutrient ◽  
Soil Bacteria And Fungi ◽  
Bacteria And Fungi ◽  
Chitinase Genes

AbstractNitrogen is a common limiting nutrient in soil in part because most N is present as macromolecular organic compounds, not directly available to plants. The microbial community present in soil near roots (rhizosphere) is in many ways analogous to the human gut microbiome, transforming nutrients present in organic substrates to forms available to plants through extracellular enzymes. Many recent studies have focused on the genetic potential for nitrogen cycling by bacteria in the rhizosphere, and on measuring inorganic N pools and fluxes. Between those two bodies of knowledge, there is scarce information on functionality of macromolecular nitrogen decomposing bacteria and fungi and how it relates to life stages of the plant. This is particularly important as many soil bacteria identified in community composition studies can be inactive or not viable. Here we use a time-series of metatranscriptomes from rhizosphere and bulk soil bacteria and fungi to follow extracellular protease and chitinase expression during rhizosphere aging. In addition, we explore the effect of adding plant litter as a source of macromolecular carbon and nitrogen. Expression of extracellular proteases increased over time in the absence of litter, more so in the presence of roots, whereas the dominant chitinase (chit1) was upregulated with exposure to litter. Structural groups of proteases were surprisingly dominated by serineproteases, possibly due to the importance of betaproteobacteria and actinobacteria in this grassland soil. Extracellular proteases of betaprotebacterial origin were more highly expressed in the presence of roots, whereas deltaroteobacteria and fungi responded to the presence of litter. We found functional guilds specializing in decomposition of proteins in the rhizosphere, detritusphere and in the vicinity of aging roots. We also identify a guild that appears to specialize in protein decomposition in the presence of roots and litter and increases its activity in aging rhizosphere, which may imply that this guild targets rhizodeposits or the senescing root itself as a protein source. Different temporal patterns of guilds imply that rather than functional redundancy, microbial decomposers operate within distinct niches.

scholarly journals The chemicals (formaldehyde and toluene) influence on soil microorganisms of leached chernozem

2016 ◽  
Vol 5 (3) ◽  
pp. 21-25
Author(s):  
Natalya Anatolyevna Ilyina ◽  
Tatyana Valentinovna Fufaeva ◽  
Natalya Anatolyevna Kazakova ◽  
Nataliya Mikhailovna Kasatkina ◽  
Evgeniya Alexandrovna Vilkova
Keyword(s):  
Soil Microorganisms ◽  
Heterotrophic Bacteria ◽  
Soil Formation ◽  
Chemical Production ◽  
Leached Chernozem ◽  
Physico Chemical ◽  
Production And Consumption ◽  
The Status ◽  
Number Of Microorganisms ◽  
Bacteria And Fungi

The paper assesses the status of the soil cover associated with the pollution of its waste chemical production and consumption. The authors present the data of formaldehyde and toluene influence on the abundance of actinomycetes, heterotrophic bacteria and fungi, as these groups of microorganisms provide self-purification capacity of the soil and participate in soil formation processes. In this paper microbiological and physico-chemical methods of research are used. The study of species composition changes of some soil microorganisms groups of leached chernozem under the influence of formaldehyde and toluene showed that this factor causes changes in the complex of soil microorganisms. This factor is reflected in the decreased species richness and diversity and increase of pollution-tolerant microorganisms. These studies investigate a number of microorganisms that provide self-purification capacity of the soil and participate in soil formation. The results show the nature of the influence of different doses of formaldehyde and toluene on the structure and functioning of the complex of soil microorganisms, as well as reveal the mechanism of action of chemicals (formaldehyde and toluene) on soil microbiota associated with its resistance and the manifestation of toxicity of the soil.

scholarly journals Organic sediment formed during inundation of a degraded fen grassland emits large fluxes of CH<sub>4</sub> and CO<sub>2</sub>

2011 ◽  
Vol 8 (6) ◽  
pp. 1539-1550 ◽  
Author(s):  
M. Hahn-Schöfl ◽  
D. Zak ◽  
M. Minke ◽  
J. Gelbrecht ◽  
J. Augustin ◽  
...  
Keyword(s):  
Organic Matter ◽  
Plant Litter ◽  
Electron Acceptors ◽  
Sediment Layer ◽  
Organic Substrates ◽  
Peat Layer ◽  
Ch4 Production ◽  
Fresh Plant ◽  
Fresh Organic Matter ◽  
Organic Sediment

Abstract. Peatland restoration by inundation of drained areas can alter local greenhouse gas emissions as CO2 and CH4. Factors that can influence these emissions include the quality and amount of substrates available for anaerobic degradation processes and the sources and availability of electron acceptors. In order to learn about possible sources of high CO2 and CH4. emissions from a rewetted degraded fen grassland, we performed incubation experiments that tested the effects of fresh plant litter in the flooded peats on pore water chemistry and CO2 and CH4. production and emission. The position in the soil profile of the pre-existing drained peat substrate affected initial rates of anaerobic CO2 production subsequent to flooding, with the uppermost peat layer producing the greatest specific rates of CO2 evolution. CH4 production rates depended on the availability of electron acceptors and was significant only when sulfate concentrations were reduced in the pore waters. Very high specific rates of both CO2 (maximum of 412 mg C d−1 kg−1 C) and CH4 production (788 mg C d−1 kg−1 C) were observed in a new sediment layer that accumulated over the 2.5 years since the site was flooded. This new sediment layer was characterized by overall low C content, but represented a mixture of sand and relatively easily decomposable plant litter from reed canary grass killed by flooding. Samples that excluded this new sediment layer but included intact roots remaining from flooded grasses had specific rates of CO2 (max. 28 mg C d−1 kg−1 C) and CH4 (max. 34 mg C d−1 kg−1 C) production that were 10–20 times lower than for the new sediment layer and were comparable to those of a newly flooded upper peat layer. Lowest rates of anaerobic CO2 and CH4 production (range of 4–8 mg C d−1 kg−1 C and <1 mg C d−1 kg−1 C) were observed when all fresh organic matter sources (plant litter and roots) were excluded. In conclusion, the presence of fresh organic substrates such as plant and root litter originating from plants killed by inundation has a high potential for CH4 production, whereas peat without any fresh plant-derived material is relatively inert. Significant anaerobic CO2 and CH4 production in peat only occurs when some labile organic matter is available, e.g. from remaining roots or root exudates.

scholarly journals Co-Occurring Anammox, Denitrification, and Codenitrification in Agricultural Soils

2012 ◽  
Vol 79 (1) ◽  
pp. 168-176 ◽  
Author(s):  
Andrew Long ◽  
Joshua Heitman ◽  
Craig Tobias ◽  
Rebecca Philips ◽  
Bongkeun Song
Keyword(s):  
Agricultural Soils ◽  
The United States ◽  
Soil Samples ◽  
Soil Incubation ◽  
Production Rates ◽  
Content Type ◽  
The North ◽  
Incubation Experiments ◽  
Bacteria And Fungi ◽  
Isotope Analyses

ABSTRACTAnammox and denitrification mediated by bacteria are known to be the major microbial processes converting fixed N to N2gas in various ecosystems. Codenitrification and denitrification by fungi are additional pathways producing N2in soils. However, fungal codenitrification and denitrification have not been well investigated in agricultural soils. To evaluate bacterial and fungal processes contributing to N2production, molecular and15N isotope analyses were conducted with soil samples collected at six different agricultural fields in the United States. Denitrifying and anammox bacterial abundances were measured based on quantitative PCR (qPCR) of nitrous oxide reductase (nosZ) and hydrazine oxidase (hzo) genes, respectively, while the internal transcribed spacer (ITS) ofFusarium oxysporumwas quantified to estimate the abundance of codenitrifying and denitrifying fungi.15N tracer incubation experiments with15NO3−or15NH4+addition were conducted to measure the N2production rates from anammox, denitrification, and codenitrification. Soil incubation experiments with antibiotic treatments were also used to differentiate between fungal and bacterial N2production rates in soil samples. Denitrifying bacteria were found to be the most abundant, followed byF. oxysporumbased on the qPCR assays. The potential denitrification rates by bacteria and fungi ranged from 4.118 to 42.121 nmol N2-N g−1day−1, while the combined potential rates of anammox and codenitrification ranged from 2.796 to 147.711 nmol N2-N g−1day−1. Soil incubation experiments with antibiotics indicated that fungal codenitrification was the primary process contributing to N2production in the North Carolina soil. This study clearly demonstrates the importance of fungal processes in the agricultural N cycle.

scholarly journals Bacterial and fungal colonization and decomposition of submerged plant litter: consequences for biogenic silica dissolution

2016 ◽  
Vol 92 (3) ◽  
pp. fiw011 ◽  
Author(s):  
Hanna Alfredsson ◽  
Wim Clymans ◽  
Johanna Stadmark ◽  
Daniel Conley ◽  
Johannes Rousk
Keyword(s):  
Biogenic Silica ◽  
Plant Litter ◽  
Fungal Colonization ◽  
Submerged Plant ◽  
Silica Dissolution

Occurrence of heterotrophic bacteria and fungi in cold and hot water distribution systems using water of different quality

1995 ◽  
Vol 41 (12) ◽  
pp. 1088-1094 ◽  
Author(s):  
Outi M. Zacheus ◽  
Pertti J. Martikainen
Keyword(s):  
Surface Water ◽  
Water Samples ◽  
Distribution Systems ◽  
Heterotrophic Bacteria ◽  
Cold Water ◽  
Hot Water ◽  
Thermophilic Fungi ◽  
Cell Counts ◽  
Bacteria And Fungi ◽  
Water Plants

The microbiological quality of cold and hot water samples of 67 Finnish buildings was studied. Most of the buildings were apartment buildings receiving their cold water from municipal groundwater or surface water plants. Disinfection with chlorine was applied in all the surface water plants and 33% of the groundwater plants. Water samples in buildings were taken from incoming cold water, from the hot water main just before and after the heat exchanger, and from a tap or shower in an apartment. The viable counts of mesophilic bacteria and fungi and total cell counts were higher in cold than in hot water samples. In hot water, the microbial counts were higher in samples from taps and showers than from the mains. In taps and showers, the decrease in hot water temperature probably increased the microbial numbers. Thermophilic bacteria appeared with high numbers in all the hot water samples, but thermophilic fungi were found in only one sample. Bacterial biomass and mean cell volume were greater in processed surface water than in processed groundwater samples. Disinfection with chlorine reduced the viable plate counts, although the chlorine concentration was extremely low in the water samples studied.Key words: heterotrophic bacteria, fungi, distribution system, groundwater, surface water.

Wastewater treatment by algal turf scrubbing

2001 ◽  
Vol 44 (11-12) ◽  
pp. 427-433 ◽  
Author(s):  
R.L. Craggs
Keyword(s):  
Wastewater Treatment ◽  
Heterotrophic Bacteria ◽  
Treated Wastewater ◽  
Algal Turf ◽  
Agricultural Drainage ◽  
Treatment Processes ◽  
Periphyton Biomass ◽  
Algal Photosynthesis ◽  
Bacteria And Fungi ◽  
Shallow Stream

Algal turf scrubbing (ATS) is a novel wetland technology that has been designed and engineered to promote natural wastewater treatment processes. Algal turf scrubbing improves water quality by passing a shallow stream of wastewater over the surface of a gently sloped floway. The floway is colonised by a natural heterogeneous assemblage of periphyton consisting of cyanobacteria, filamentous algae and epiphytic diatoms together with aerobic bacteria and fungi. Algal photosynthesis provides oxygen for aerobic breakdown of wastewater by heterotrophic bacteria. Pollutants are extracted from the wastewater by several processes including assimilation, adsorption, filtration and precipitation. The algal turf is harvested periodically to remove the accumulated periphyton biomass and associated pollutants from the system. This paper will present results from a demonstration ATS facility in Patterson, California which was used to polish secondarily treated wastewater. The design and operational factors that influence the treatment performance of ATS systems is discussed. Results indicate the potential of the ATS for nutrient removal from secondarily treated wastewater and agricultural drainage waters.

The use of radiation-sterilized soil to study the ammonium nutrition of wheat

Soil Research ◽  
1969 ◽  
Vol 7 (1) ◽  
pp. 57 ◽  
Author(s):  
AD Rovira ◽  
GD Bowen
Keyword(s):  
Plant Growth ◽  
Gamma Radiation ◽  
Heterotrophic Bacteria ◽  
Natural Conditions ◽  
Nitrogen Turnover ◽  
Ammonium N ◽  
Unsterilized Soil ◽  
Ammonium Nutrition ◽  
Bacteria And Fungi

The recolonization by Nitrosomonas and Nitrobacter of a soil sterilized by gamma radiation was extremely slow compared with the rates of recolonization by heterotrophic bacteria and fungi. As a consequence, ammonium N formed during and following irradiation was not nitrified for at least 11 weeks and plants growing on irradiated inoculated soil were ammonia fed. Under these conditions plant growth was better in irradiated-inoculated soil than in unsterilized soil. After 3 weeks, wheat from irradiated inoculated soil had three times the asparagine content found in wheat from unsterilized soil. Soil that has been irradiated then inoculated could be a useful tool for studying both nitrogen turnover in soil and the availability of nitrate and ammonium to plants growing in soil under nearly natural conditions.

Pseudomonas putida inoculation promotes submerged plant Vallisneria natans growth by carbon conversion in a plant–microbe interaction

2018 ◽  
Vol 69 (5) ◽  
pp. 851
Author(s):  
Lin Gan ◽  
Hui Zhao ◽  
Aili Wang ◽  
Sanshan Li ◽  
Jia Liu ◽  
...  
Keyword(s):  
Plant Growth ◽  
Pseudomonas Putida ◽  
Leaf Area ◽  
Heterotrophic Bacteria ◽  
Dissolved Inorganic Carbon ◽  
Light Limitation ◽  
Co2 Uptake ◽  
Carbon Conversion ◽  
Submerged Plant ◽  
Vallisneria Natans

Submerged plant growth is limited by the reduction of underwater photosynthesis attributed to low CO2 availability, as well as light limitation associated with underwater conditions. Heterotrophic bacteria and fungi play an important role in local aqueous dissolved inorganic carbon (DIC) content surrounding submerged plants. In order to investigate the effects of carbon conversion in plant–microbe interactions on plant growth, in the present study we inoculated the plant medium of Vallisneria natans with Pseudomonas putida KT2440 and measured carbon conversion in the system, as well as several indices of plant growth. The quantity of P. putida KT2440 increased twofold because of the availability of organic matter produced by V. natans. Similarly, P. putida KT2440 supplied DIC for V. natans, improving its photosynthetic rate. Moreover, the significantly higher leaf area, specific leaf area and fresh biomass of V. natans attributed to the presence of P. putida KT2440 demonstrated that the interaction between V. natans and P. putida enhanced the efficiency of nutrient and CO2 uptake by V. natans, promoting V. natans growth. Therefore, we suggest that the carbon and oxygen microcycle based on the protocooperation of V. natans and P. putida KT2440 may accelerate the transformation of carbon to increase carbon availability to promote the growth of both plant and microbe.

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