Bacterial Diversity Patterns Differ in Soils Developing in Sub-tropical and Cool-Temperate Ecosystems.

Microbial diversity patterns have been surveyed in many different soils and ecosystems, but we are unaware of studies comparing similar soils developing from similar parent materials in contrasting climates. In 2008, developmental chronosequences with ages ranging from 105 to 500,000 years across Georgia (GA) and Michigan (MI) were studied to investigate how bacterial community composition and diversity change as a result of local environmental gradients that develop during pedogenesis. Geographic factors were studied between and within locations spanning two scales: (1) regionally between 0.

Fecal coliform modeling under two flow scenarios in St. Louis Bay of Mississippi.

St. Louis Bay, along with its two major tributaries, Wolf River and Jourdan River, are included in the Mississippi 1998 Section 303(d) List for violation of the designated water use of recreation and shellfish harvesting. Fecal coliform was identified as one of the pollutants that caused the water quality impairment.

Online high-performance size exclusion chromatography-nuclear magnetic resonance for the characterization of dissolved organic matter.

The substantial heterogeneity of dissolved organic matter (DOM) inhibits detailed chromatographic analysis with conventional detectors as little structural information can be obtained in the presence of extensive coelution. Here we examine the direct hyphenation of high-performance size exclusion chromatography (HPSEC) with nuclear magnetic resonance (NMR) spectroscopy to determine how size-distinguished fractions differ in composition. The results support the applicability of using HPSEC to generate more homogeneous fractions of DOM prior to NMR analysis and demonstrate that structure is significantly altered with size.

Application and evaluation of two nutrient algorithms of Hydrological Simulation Program Fortran in Wolf River watershed.

This study performs a comparison of two nutrient algorithms of Hydrological Simulation Program Fortran, PQUAL/IQUAL and AGCHEM. Watershed nutrient models with, PQUAL/IQUAL and AGCHEM, were developed and calibrated separately with observed data in the Wolf River watershed. Compared to AGCHEM modules, the PQUAL/IQUAL algorithm was found to have several disadvantages.

Modeling nutrient dynamics under critical flow conditions in three tributaries of St. Louis Bay.

Previous research results indicated that dry weather condition has complicated impacts on nitrogen dynamics; monitored and modeling data showed both increased and decreased levels. In order to facilitate the total maximum daily loads (TMDLs) development at three tributaries of St. Louis Bay estuary, the nitrogen dynamics were investigated for two designed critical flow conditions by integrating Hydrological Simulation Program Fortran (HSPF), Environmental Fluid Dynamics Code (EFDC), and Water Quality Analysis Simulation Program (WASP).

Watershed modeling of dissolved oxygen and biochemical oxygen demand using a hydrological simulation Fortran program.

Several inland water bodies in the St. Louis Bay watershed have been identified as being potentially impaired due to low level of dissolved oxygen (DO). In order to calculate the total maximum daily loads (TMDL), a standard watershed model supported by U.

1H and 19F nuclear magnetic resonance microimaging of water and chemical distribution in soil columns.

Nuclear magnetic resonance (NMR) microimaging is a noninvasive and nondestructive technique that has great potential for the study of soil processes. Hydrogen-1 NMR microimaging techniques were used to examine the distribution of water in four different soil cores. Fluorine-19 NMR microimaging is also used to study the transport of three model contaminants (hexafluorobenzene, sodium fluoride, and trifluralin) in soil columns.

Degradation and sorption of fluometuron and metabolites in conservation tillage soils.

Soil sorption and dissipation of fluometuron (FLM) and three metabolites, desmethyl fluometuron (DMF), trifluoromethyl phenyl urea (TFMPU), and trifluoromethyl aniline (TFMA), were assessed in conservation tillage soils. In study I, surface Dundee silt loam soils from no-tillage (NT) and reduced-tillage (RT) areas were treated with 14C ring-labeled FLM or TFMA or unlabeled DMF, incubated for 34-42 days, extracted, and analyzed. Mineralization and volatilization of 14C-labeled FLM or TFMA were monitored.

The application of 1H high-resolution magic-angle spinning NMR for the study of clay-organic associations in natural and synthetic complexes.

The preferential sorption of model compounds to calcium-exchanged montmorillonite surfaces was investigated using 1H high-resolution magic-angle spinning (HR-MAS) and liquid-state NMR. Synthetic mixtures, representing the major structural categories abundant in natural organic matter (NOM), and two soil extracts were sorbed to montmorillonite. The NMR spectra indicate that, of the organic components observable by 1H HR-MAS NMR, aliphatic components preferentially sorb to the clay surface, while carbohydrates and amino acids mainly remain in the supernatant.

The application of LC-NMR and LC-SPE-NMR to compositional studies of natural organic matter.

Non-living natural organic matter (NOM) is ubiquitous in the oceans, atmosphere, sediments, and soils, and represents the most abundant organic carbon reserves on earth. However, a large proportion is considered to be "molecularly uncharacterized" because the inherent complexity of NOM is problematic when applying conventional analytical techniques. This manuscript presents initial applications of LC-NMR (1H) and LC-SPE-NMR (1H) to the studies of NOM isolated from water and soil.

Identifying residues in natural organic matter through spectral prediction and pattern matching of 2D NMR datasets.

This paper describes procedures for the generation of 2D NMR databases containing spectra predicted from chemical structures. These databases allow flexible searching via chemical structure, substructure or similarity of structure as well as spectral features. In this paper we use the biopolymer lignin as an example.

The identification of plant derived structures in humic materials using three-dimensional NMR spectroscopy.

Here we demonstrate the application of 3-D NMR spectroscopy to structural studies of humic substances, the most abundant of organic compounds on earth. The increased spectral dispersion provided by the additional dimension is proven to be highly advantageous in separating the overlapping signals observed in 2-D spectra. Assignments of the major aliphatic structures and selected aromatic moieties are given as examples.

Industrial age anthropogenic inputs of heavy metals into the pedosphere.

Heavy metals have been increasingly released into our environment. We present here, for the first time, the global industrial age production of Cd, Cu, Cr, Hg, Ni, Pb, and Zn, and their potential accumulation and environmental effects in the pedosphere. World soils have been seriously polluted by Pb and Cd and slightly by Zn.

Molecular structures and associations of humic substances in the terrestrial environment.

Here we show, for the first time, evidence of the primary molecular structures in humic substances (HS), the most abundant naturally occurring organic molecules on Earth, and their associations as mixtures in terrestrial systems. Multi-dimensional nuclear magnetic resonance (NMR) experiments show us that the major molecular structural components in the mixtures operationally defined as HS are aliphatic acids, ethers, esters and alcohols; aromatic lignin derived fragments; polysaccharides and polypeptides. By means of diffusion ordered spectroscopy, distinct diffusion coefficients consistent with relatively low molecular weight molecules were observed for all the components in the mixtures, and saccharides were the largest single class of component present.

Improvements in the two-dimensional nuclear magnetic resonance spectroscopy of humic substances.

Understanding pollutant sorption, bioremediation of these pollutants, and their interactions with humic substances requires knowledge of molecular-level processes. New developments with nuclear magnetic resonance (NMR) experiments and labeled compounds have improved the overall understanding of these mechanisms. The advancements made with two-dimensional NMR show great promise, as structural information and hydrogen-carbon bond connectivity can be discerned.

Pathways and kinetics of redistribution of cobalt among solid-phase fractions in arid-zone soils under saturated regime.

An adequate supply of Co in pasture is important to the health of grazing animals. Bio-availability of Co in soils is largely depended upon its distribution among solid-phase fractions. Distribution of cobalt in six arid-zone soils and its redistribution among the solid-phase fractions during long-term saturated paste incubation were studied.