scholarly journals Abundance and Diversity of Viruses in Six Delaware Soils

2005 ◽  
Vol 71 (6) ◽  
pp. 3119-3125 ◽  
Author(s):  
Kurt E. Williamson ◽  
Mark Radosevich ◽  
K. Eric Wommack
Keyword(s):  
Land Use ◽  
Forest Soils ◽  
Agricultural Soils ◽  
Dry Weight ◽  
Morphological Data ◽  
Epifluorescence Microscopy ◽  
Viral Abundance ◽  
Wide Range ◽  
Virus Communities ◽  
Abundance And Diversity

ABSTRACT The importance of viruses in marine microbial ecology has been established over the past decade. Specifically, viruses influence bacterial abundance and community composition through lysis and alter bacterial genetic diversity through transduction and lysogenic conversion. By contrast, the abundance and distribution of viruses in soils are almost completely unknown. This study describes the abundance and diversity of autochthonous viruses in six Delaware soils: two agricultural soils, two coastal plain forest soils, and two piedmont forest soils. Viral abundance was measured using epifluorescence microscopy, while viral diversity was assessed from morphological data obtained through transmission electron microscopy. Extracted soil virus communities were dominated by bacteriophages that demonstrated a wide range of capsid diameters (20 nm to 160 nm) and morphologies, including filamentous forms and phages with elongated capsids. The reciprocal Simpson's index suggests that forest soils harbor more diverse assemblages of viruses, particularly in terms of morphological distribution. Repeated extractions of virus-like particles (VLPs) from soils indicated that the initial round of extraction removes approximately 70% of extractable viruses. Higher VLP abundances were observed in forest soils (1.31 × 109 to 4.17 × 109 g−1 dry weight) than in agricultural soils (8.7 × 108 to 1.1 × 109 g−1 dry weight). Soil VLP abundance was significantly correlated to moisture content (r = 0.988) but not to soil texture. Land use (agricultural or forested) was significantly correlated to both bacterial (r = 0.885) and viral (r = 0.812) abundances, as were soil organic matter and water content. Thus, land use is a significant factor influencing viral abundance and diversity in soils.

scholarly journals Soil-Atmosphere CO Exchanges and Microbial Biogeochemistry of CO Transformations in a Brazilian Agricultural Ecosystem

2002 ◽  
Vol 68 (9) ◽  
pp. 4480-4485 ◽  
Author(s):  
Gary M. King ◽  
M. Hungria
Keyword(s):  
Land Use ◽  
Co Oxidation ◽  
Forest Soils ◽  
Dry Weight ◽  
Ambient Conditions ◽  
Agricultural Ecosystem ◽  
Soil Atmosphere ◽  
Cultivated Plant ◽  
Tillage Method ◽  
Cultivated Soils

ABSTRACT Although anthropogenic land use has major impacts on the exchange of soil and atmosphere gas in general, relatively little is known about its impacts on carbon monoxide. We compared soil-atmosphere CO exchanges as a function of land use, crop type, and tillage treatment on an experimental farm in Parãna, Brazil, that is representative of regionally important agricultural ecosystems. Our results showed that cultivated soils consumed CO at rates between 3 and 6 mg of CO m−2 day−1, with no statistically significant effect of tillage method or crop. However, CO exchange for a pasture soil was near zero, and an unmanaged woodlot emitted CO at a rate of 9 mg of CO m−2 day−1. Neither nitrite, aluminum sulfate, nor methyl fluoride additions affected CO consumption by tilled or untilled soils from soybean plots, indicating that CO oxidation did not depend on ammonia oxidizers and that CO oxidation patterns differed in part from patterns reported for forest soils. The apparent Km for CO uptake, 5 to 11 ppm, was similar to values reported for temperate forest soils; V max values, approximately 1 μg of CO g (dry weight)−1 h−1, were comparable for woodlot and cultivated soils in spite of the fact that the latter consumed CO under ambient conditions. Short-term (24-h) exposure to elevated levels of CO (10% CO) partially inhibited uptake at lower concentrations (i.e., 100 ppm), suggesting that the sensitivity to CO of microbial populations that are active in situ differs from that of known carboxydotrophs. Soil-free soybean and corn roots consumed CO when they were incubated with 100-ppm concentrations and produced CO when they were incubated with ambient concentrations. These results document for the first time a role for cultivated plant roots in the dynamics of CO in an agricultural ecosystem.

The effect of organic amendment, water content, and oxygen on the incorporation of 15N2 by some agricultural and forest soils

1969 ◽  
Vol 15 (8) ◽  
pp. 899-905 ◽  
Author(s):  
R. Brouzes ◽  
J. Lasik ◽  
R. Knowles
Keyword(s):  
Forest Soils ◽  
Organic Amendment ◽  
Agricultural Soils ◽  
Dry Weight ◽  
Anaerobic Conditions ◽  
Litter Addition ◽  
Consistent Effect ◽  
Ph Values ◽  
Area Basis ◽  
Profile Depth

Thirty samples of nine soil profiles were variously treated and incubated in aerobic and in anaerobic 15N-labelled atmospheres in the laboratory. The addition of glucose to agricultural soils stimulated nitrogen fixation, especially under anaerobic conditions, but glucose had little or no consistent effect in most forest soils. The addition of straw litter to aerobically incubated waterlogged agricultural soils caused increased fixation. In general, however, and especially in forest soils, there was no consistent effect of either litter addition or waterlogging. It may be noted that in many cases greater fixation occurred in waterlogged soil–litter mixtures when incubated anaerobically than when incubated aerobically. About 80% of all treatments showed greater fixation under anaerobic than under aerobic conditions. Nitrogen incorporation during 28 days at 25 °C ranged from 0 to 70 μg N/g dry weight. Estimates on an area basis for a 17-cm profile depth ranged from 2 to 200 kg N fixed/ha per year.Azotobacter was confined to agricultural soils above about pH 6.5. Clostridium was widely distributed and usually abundant even in soils with pH values as low as 3.3. "Oligonitrophiles" were abundant but their significance remains uncertain.

scholarly journals An Inexpensive, Accurate, and Precise Wet-Mount Method for Enumerating Aquatic Viruses

2015 ◽  
Vol 81 (9) ◽  
pp. 2995-3000 ◽  
Author(s):  
Brady R. Cunningham ◽  
Jennifer R. Brum ◽  
Sarah M. Schwenck ◽  
Matthew B. Sullivan ◽  
Seth G. John
Keyword(s):  
Cost Effective ◽  
Epifluorescence Microscopy ◽  
Viral Abundance ◽  
Ceramic Filters ◽  
Metabolic Functions ◽  
Wet Mount ◽  
Wide Range ◽  
Viral Isolates ◽  
Freshwater Environments

ABSTRACTViruses affect biogeochemical cycling, microbial mortality, gene flow, and metabolic functions in diverse environments through infection and lysis of microorganisms. Fundamental to quantitatively investigating these roles is the determination of viral abundance in both field and laboratory samples. One current, widely used method to accomplish this with aquatic samples is the “filter mount” method, in which samples are filtered onto costly 0.02-μm-pore-size ceramic filters for enumeration of viruses by epifluorescence microscopy. Here we describe a cost-effective (ca. 500-fold-lower materials cost) alternative virus enumeration method in which fluorescently stained samples are wet mounted directly onto slides, after optional chemical flocculation of viruses in samples with viral concentrations of <5 × 107viruses ml−1. The concentration of viruses in the sample is then determined from the ratio of viruses to a known concentration of added microsphere beads via epifluorescence microscopy. Virus concentrations obtained by using this wet-mount method, with and without chemical flocculation, were significantly correlated with, and had precision equivalent to, those obtained by the filter mount method across concentrations ranging from 2.17 × 106to 1.37 × 108viruses ml−1when tested by using cultivated viral isolates and natural samples from marine and freshwater environments. In summary, the wet-mount method is significantly less expensive than the filter mount method and is appropriate for rapid, precise, and accurate enumeration of aquatic viruses over a wide range of viral concentrations (≥1 × 106viruses ml−1) encountered in field and laboratory samples.

Patterns in diversity and composition of the microbenthos of subarctic intertidal beaches with different morphodynamics

2020 ◽  
Vol 648 ◽  
pp. 19-38
Author(s):  
AI Azovsky ◽  
YA Mazei ◽  
MA Saburova ◽  
PV Sapozhnikov
Keyword(s):  
Species Abundance ◽  
Abundance Ratio ◽  
Wave Action ◽  
Coarse Grained ◽  
Sediment Properties ◽  
Β Diversity ◽  
Α Diversity ◽  
Wide Range ◽  
Similar Mode ◽  
Abundance And Diversity

Diversity and composition of benthic diatom algae and ciliates were studied at several beaches along the White and Barents seas: from highly exposed, reflective beaches with coarse-grained sands to sheltered, dissipative silty-sandy flats. For diatoms, the epipelic to epipsammic species abundance ratio was significantly correlated with the beach index and mean particle size, while neither α-diversity measures nor mean cell length were related to beach properties. In contrast, most of the characteristics of ciliate assemblages (diversity, total abundance and biomass, mean individual weight and percentage of karyorelictids) demonstrated a strong correlation to beach properties, remaining low at exposed beaches but increasing sharply in more sheltered conditions. β-diversity did not correlate with beach properties for either diatoms or ciliates. We suggest that wave action and sediment properties are the main drivers controlling the diversity and composition of the intertidal microbenthos. Diatoms and ciliates, however, demonstrated divergent response to these factors. Epipelic and epipsammic diatoms exhibited 2 different strategies to adapt to their environments and therefore were complementarily distributed along the environmental gradient and compensated for each other in diversity. Most ciliates demonstrated a similar mode of habitat selection but differed in their degree of tolerance. Euryporal (including mesoporal) species were relatively tolerant to wave action and therefore occurred under a wide range of beach conditions, though their abundance and diversity were highest in fine, relatively stable sediments on sheltered beaches, whereas the specific interstitial (i.e. genuine microporal) species were mostly restricted to only these habitats.

SOME TRENDS IN GRASSLAND FARMING IN EUROPE

1977 ◽  
pp. 5-19
Author(s):  
R.W. Brougham
Keyword(s):  
Land Use ◽  
Crude Protein ◽  
Energy Usage ◽  
Hill Country ◽  
Wide Range

IN an assessment such as this, one could cover a wide range of topics fairly shallowly or a lesser number in a bit more depth. I have opted for the latter. The topics discussed will embrace some trends in dairying, beef farming, sheep farming, hill country farming, and land use generally, species and variety usage in grassland farming, use of crude protein produced from pasture, and some implications of energy usage.

Key directions and methodological features of modern studies of land use changes

2019 ◽  
pp. 62-68
Author(s):  
Pavlo Kazmir ◽  
Lyubomyr Kazmir
Keyword(s):  
Land Use ◽  
Land Use Changes ◽  
Scientific Discipline ◽  
Shared Responsibility ◽  
Management Tools ◽  
Land Change Science ◽  
Wide Range ◽  
Land Relations ◽  
Future Policy ◽  
Planning Methodology

Interest in land-use changes (LUC) research has been growing rapidly in recent years. This topic has already become the subject of a separate scientific discipline – land use science (or land change science). In order to formulate relevant future policy and develop appropriate land-use management tools, it is crucial to know how the LUC шьзфсе the environment and society condition. For Ukraine, where the structure of land use and the system of land resources management have significantly changed during the years of post-socialist transformation of land relations, the study of the LUC on a modern methodological basis is especially actual. The paper, based on a critical analysis of publications in leading international journals over the last thirty years, identifies key directions of LUC studies and analyzes their methodological features. There is a significant increase of the number of works based on the results of meta-studies and the use of a wide range of methods for modeling the LUC processes, their causes and possible consequences. The great "synergistic potential" of integration of the selected directions is noted, which makes it possible to accelerate the development of the general theory of land use and increase its use efficiency in substantiation of management decisions in the sphere of land use and modernization of the mechanisms of state land, spatial and ecological policies with consideration of existing and potential globalizing challenges. In this context, the key role of the land use integrated planning methodology at regional and local levels is emphasized. This methodology would require close cooperation between government, business and the public in developing a common vision for the implementation of specific land use plans and projects based on the principles of subsidiarity, participativity and shared responsibility.

Analysis of Land Use Land Cover in Annapurna Conservation Area in Gandaki Province, Nepal using Vegetation Index and Land Use Land Cover Datasets

2019 ◽  
Vol 2 (2) ◽  
pp. 87-99
Author(s):  
Shiva Pokhrel ◽  
Chungla Sherpa
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Vegetation Index ◽  
National Level ◽  
Climate Mitigation ◽  
Land Use Land Cover ◽  
Conservation Area ◽  
Barren Land ◽  
Wide Range ◽  
Annapurna Conservation Area

Conservation areas are originally well-known for protecting landscape features and wildlife. They are playing key role in conserving and providing a wide range of ecosystem services, social, economic and cultural benefits as well as vital places for climate mitigation and adaptation. We have analyzed decadal changes in land cover and status of vegetation cover in the conservation area using both national level available data on land use land cover (LULC) changes (1990-2010) and normalized difference vegetation index (NDVI) (2010-2018) in Annapurna conservation area. LULC showed the barren land as the most dominant land cover types in all three different time series 1990, 2000 and 2010 with followed by snow cover, grassland, forest, agriculture and water body. The highest NDVI values were observed at Southern, Southwestern and Southeastern part of conservation area consisting of forest area, shrub land and grassland while toward low to negative in the upper middle to the Northern part of the conservation area.

scholarly journals Current Wildland Fire Patterns and Challenges in Europe: A Synthesis of National Perspectives

2021 ◽  
Vol 14 ◽  
pp. 117862212110281
Author(s):  
Nieves Fernandez-Anez ◽  
Andrey Krasovskiy ◽  
Mortimer Müller ◽  
Harald Vacik ◽  
Jan Baetens ◽  
...  
Keyword(s):  
Land Use ◽  
Large Scale ◽  
Wildland Fire ◽  
Human Life ◽  
Local Analysis ◽  
Wildland Fires ◽  
Fire Statistics ◽  
Quantitative Evidence ◽  
Wide Range ◽  
Fire Patterns

Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009–2018) across Europe. For each of the 31 countries included, we present a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action “Fire and the Earth System: Science & Society” funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wildland fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3) against more robust quantitative evidence.

scholarly journals Abandoned agricultural soils from the central part of the Yamal region of Russia: morphology, diversity, and chemical properties

2020 ◽  
Vol 5 (1) ◽  
pp. 94-106
Author(s):  
Evgeny Abakumov ◽  
Evgeniya Morgun ◽  
Alexandr Pechkin ◽  
Vyacheslav Polyakov
Keyword(s):  
Land Use ◽  
Agricultural Soils ◽  
Anthropogenic Impacts ◽  
Chemical Properties ◽  
Organic Carbon Content ◽  
Active Growth ◽  
Natural Processes ◽  
Agrochemical Properties ◽  
Fallow Lands ◽  
Abandoned Lands

AbstractThe post-anthropogenic and soil cover transformations of former agricultural soils on the abandoned lands in the Russian Arctic territory are poorly investigated due to the active growth of the city complexes and increasing area occupied by agricultural lands. That is lead to an increase in the area of the arable lands surrounding the polar urbanized territories. Today, most of that land allocated for agricultural needs has been abandoned or affected by other types of land use. This study aimed to investigate the abandoned lands surrounding some of the settlements in the central part of the Yamal region. The soil diversity, morphology, and chemical and agrochemical properties were investigated with special reference to the specific transformations that occur to fallow lands under permafrost-affected cryogenic-ecosystem conditions. Analysis of data show that these soils are characterized by features relating to both, previous (and existing), anthropogenic impacts and natural processes such as cryogenic mass transfer. The degradation of the arable humus-enriched horizon was not as pronounced as it has been in more humid boreal environments over recent decades. The organic carbon content in topsoil depends on the land use and varied considerably among the soil types. The former arable topsoil horizon has been stable over time in terms of its morphological features and agrochemical state. Despite the high soil acidity levels, thenutrient content in the anthropogenically impacted soils was still high, even though being abandoned for 20 years.

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