Thesis (M.S.)--University of Michigan, 1994. / eContent provider-neutral record in process. Description based on print version record.

Thesis (Ph.D.)--Murdoch University, 2009. / Thesis submitted to the Faculty of Sustainability, Environmental and Life Sciences. Includes bibliographical references (leaves 201-242)

Thesis (M. Sc. Agriculture (Soil Science)) -- University of Limpopo, 2016 / This study aimed at assess phosphorus (P) solubility and bioavailability from non-reactive Phalaborwa ground phosphate rock (GPR) using thermophilic co-composting technology. Two types of organic wastes (Cattle, CM and poultry manure, PM) were used to produce different mix ratios (5:5, 7:3, 8:2 and 9:1) of phospho-composts. Control compost of both manures without GPR addition were included. Samples of each compost heap were taken at mesophilic, thermophilic, cooling and maturity stages and used for bioquality and chemical tests. Microbial counts, enzyme activity, molecular analysis, and the quatification of different P forms and fractions were carried out on all compost samples. Results showed that the concentration of P measured in the different phospho-composts differed significantly (p < 0.05). The 8:2 mix ratio gave quantitatively higher P concentration in both CM- and PM-based phospho-composts. Organic P form had the lowest concentration when compared to other P forms and fractions while water soluble-P had the highest concentration as compared to other P fractions. The content of actinomycetes showed correlated positively with EC, phosphatase β-glucosidase, fungi and bacteria but negatively correlated with organic P, Ca-P water P and pH. There was a positive and significant correlation between electrical conductivity, enzyme activity (phosphatase, dehydrogenase and β-glucosidase), fungi, actinomycete and P fractions (Bray P1, Ca-P and Pi value). Acid phosphatase activity correlated negatively with water extractable P, organic P and Ca-P contents but revealed a positively significant correlation with bacteria, fungi and actinomycete counts. Generally higher microbial counts were measured in CM- than PM-based phospho-composts but the concentrations varied with each microbial species. Highest fungi (7.27 CFU g-1) and actinomycete (6.83 CFU g-1) counts were generally recorded in the control composts, which was quantitatively higher in CM- than PM-based phospho-composts. Quantitatively higher enzyme activities were measured across compost types and mix ratios during the cooling phase phospho-compost production; but were statistically comparable to measured values at maturity phase. Acid phosphatase and β-glucosidase enzymes were predominately higher at maturity phase in all cattle manure-based phospho-compost excluding the 5:5 mix ratio. In PM-based phospho-compost, both β-glucosidase and phosphatase were higher at initial phase with PM5:5 , PM9:1 and PM10:0. Dehydrogenase activities were predominately higher at thermophilic and cooling phase from both PM- and CM-based phospho-compost. Results of molecular analysis revealed that Bacillus sp. and Acholeplasma cavigenitalium sp. were dorminant in PM-based phospho-composts while Pseudomonas sp. and Acholeplasma pleciae dorminated the CM-based phospho-composts. In conclusion, results of this study revealed that the type of manure used exerts great influence on the bioquality parameters and the amount of P released. Key words: Phospho-compost, Compost quality, Enzyme activities, Nutrient cycling, Ground phosphate rock, Phosphorus forms and fractions

Indiana University-Purdue University Indianapolis (IUPUI) / Phosphorus (P) is essential for aquatic life; cycling between both inorganic and organic forms to maintain an ecological balance. Its addition into P-scarce freshwaters, either through terrestrial (external) or sedimentary (internal) loading, may disrupt this balance causing blooms of phytoplankton to flourish, often resulting in harmful environmental and anthropogenic consequences. Accordingly, reduction of external P loading has been commonly implemented with a recent focus on sediment-bound legacy P that is mobilized into the water column during dynamic redox conditions. Mobile P species have been identified as both inorganic and organic, with the former representing the most bioavailable fraction, and the latter serving as a source for labile P in freshwaters when in high demand, particularly during blooms. Missisquoi Bay in Lake Champlain, VT experiences harmful cyanobacterial blooms driven by internal P loading and has been the target of numerous geochemical and hydrological studies. This thesis describes a high-resolution investigation of both the organic P and organic matter compositions of the bay with respect to mobility, reactivity, and bioavailability using Fourier Transform-Ion Cyclotron Mass Spectrometry (FT-ICR MS). Sediment from Missisquoi Bay was extracted with a diverse set of reagents, resulting in fractionation of both organic matter and organic P, and illustrating the distribution of various labile and recalcitrant compounds. Many of these molecules are associated with porewater or easily extractable mineral surfaces providing a link to the benthic organic matter and phosphorus fractions available to microorganisms. Additionally, the organic chemistry of the bay was investigated seasonally from May 2017 to January 2018 revealing biological processing from the spring runoff season through the post-bloom summer season. The transition from late summer to under ice conditions in winter was less severe with a higher commonality between both organic matter and organic P compounds, suggesting reduced biological and abiotic degradation. Moreover, short-term anoxic incubations of sediment cores from each season revealed the presence of diverse organic signatures from sorption processes, and a significant contribution of benthic microbial activity to the benthic organic geochemistry.

No description available.

Harmful algal blooms (HABs) can be detrimental to ecosystems, human health, and economies. The low levels of phosphorus remaining in the effluent of municipal wastewater treatment plants can contribute to HAB formation. To achieve more complete phosphorus removal, an effluent treatment method has been proposed that uses phosphorus-deprived, filamentous microalgae to quickly assimilate soluble phosphorus to low concentrations. This study investigated two parameters that influence the feasibility of such a system: (1) the biomass growth productivity of algal cultures during the phosphorus deprivation period and (2) the correlation between the duration of this period and the phosphorus uptake rate by the biomass when contacted with the water to be treated. A single strain of filamentous algae, Tribonema minus, was used. Two experiments lasting 8-9 days compared the biomass productivity of cultures of T. minus grown in phosphorus-replete and -deplete media. While no significant difference in productivity was observed between treatments, further studies should be done to confirm this finding. In addition, 39 uptake contact experiments were conducted. The soluble phosphorus uptake rate was measured for algae deprived of phosphorus for 0 to 12 days of growth. The highest observed uptake rate was 3.83 mg P/g VSS-h, during the first three hours of contact, by biomass that had been phosphorus-deprived for 12 days. The correlation between phosphorus deprivation duration and 3-h uptake rate was 0.34 mg P/g VSS-h per day of deprivation (R2 = 0.81). Additional development efforts seem justified based on these results.

No description available.

The measurement of phosphorus which is available to plants is a problem closely related to the forms and amounts of phosphorus present in soils. The fractionation of soil phosphorus, based on a series of extractions, is a procedure that has been utilized by many investigators. In this study, this scheme was utilized in an attempt to improve and evaluate the effectiveness of some methods employed in the measurement of available phosphorus to plants. / Ph. D.

A nutrient is defined as a chemical element necessary for life. In streams, phosphorus is typically one of the most important nutrients and often limits microbial (algae, bacteria, and fungi) growth. As a result, retention of phosphorus within streams largely determines productivity. Factors that influence retention include temperature (Elwood et al. 1981b), velocity (Bencala 1983), and organic matter (Mulholland et al. 1984). Watershed input-output budgets have been commonly used to evaluate nutrient retention characteristics (Borman et al. 1974). These studies provide information about nutrient flux through ecosystems but offer little information about mechanisms governing nutrient dynamics. In contrast, nutrient spiralling, as described by Webster and Patten (1979), provides a method to evaluate retention and the mechanisms governing it. A nutrient spiral is defined as the distance traveled by a nutrient ion as it completes one cycle from dissolved form to particulate form and back to dissolved form. The distance a nutrient ion travels in dissolved form is called the uptake length and typically accounts for > 90% of spiralling length (Newbold et al. 1983). Uptake length is commonly used instead of spiralling length, because unlike spiralling length, uptake length can be measured without the use of radiotracers. Nutrient spiralling, developed in the late 70's and early 80's, is a relatively new concept. Work on spiralling length (or uptake length) has just begun to allude to possible mechanisms of solute retention and the relative importance of these mechanisms (see Solute Working Group 1990 for a review of concepts and methodology). Recent nutrient retention studies have shown phosphorus retention to be affected by both physical (e.g. temperature, velocity) and biological (e.g. microbial activity, organic matter biomass) factors. However, these studies have yielded conflicting information as to the relative importance of these factors. For example, Gregory (1978) and Elwood et al. (1981) demonstrated that uptake was mostly biotic, while Meyer (1979) found that uptake was determined by physical factors in the streams she studied. This contradiction suggests that streams may range from those driven primarily by biological mechanisms to streams driven almost entirely by physical factors with most streams falling somewhere between these extremes. The relative importance of physical and biological factors may vary spatially and temporally within a stream. This study was designed to systematically identify and examine factors that influence nutrient retention. More specifically, the objectives of this study were: 1) Examine microbial colonization and breakdown characteristics of leaves with different amounts of structural rigidity, under different constrainment techniques, to gain insight into how these characteristics may affect nutrient retention. 2) Use artificial streams to separate and identify factors governing nutrient retention by controlling flow and using different amounts and types of leaf material. 3) Evaluate how land-use practices may alter phosphorus retention mechanisms by comparing results of nutrient releases in natural streams draining undisturbed mixed hardwood watersheds with releases in streams draining disturbed watersheds (i.e. watersheds that had been logged and planted in white pine). / Ph. D.

Call number: LD2668 .T4 1937 H61