Eugene T. Premuzic

The nature and distribution of organic matter in the surface sediments of world oceans and seas

Existing data on the distribution of organic carbon and nitrogen in marine sediments have been analyzed in order to better understand the physical and chemical processes involved in this aspect of the global carbon cycle. Maps of the global distribution of organic carbon and nitrogen in the sediments of world oceans and seas are presented. Correlation analyses of the available information dealing with the distribution of marine sedimentary organic matter has revealed that in terms of bulk parameters (%COrg and %N Kjeldahl), there is an apparent accumulation of organic matter on the continental slope (water column depth 200–2000 m). Specific interactions between clays and organic matter, although indicated in laboratory experiments, have not been detected by these analyses.

Organic storage of CO2 on the continental slope off the mid-Atlantic bight, the southeastern Bering Sea, and the Peru Coast

A comparison is made of organic content, sedimentation rates derived from 14C and 210Pb analyses, 13C and 15N isotope ratios, amorphous silica, particle size, and calcium carbonate within sediments from slopes off the mid-Atlantic bight, the southeastern Bering Sea, and the Peru coast. These sediments are mainly marine, diatom-rich, and about one-third of the organic carbon is recent, reflecting a possible transient of shelf export in response to mans increased activities since the industrial revolution. Using a combination of sedimentation and mixing rates of carbon, the C:N ratio of sediments within the upper 50 cm, and the amount of nitrogen thought to be released from the coastal zone, independent estimates suggest a carbon loading to world slopes of ∼0.3 to 0.5 × 109 tons C y−1. The Bering slope exhibits no anthropogenic transients, however, while increased carbon loading may have occurred off Peru in response to overfishing and off the mid-Atlantic bight in response to eutrophication. The generality of our results depends on which of the three systems is most representative of world slopes.

Induced Formation of Chelating Agents by Pseudomonas aeruginosa Grown in Presence of Thorium and Uranium

Chelating agents produced by microorganisms enhance the dissolution of iron and increase its mobility and bioavailability. Since there are some similarities in the biological behavior of ferric, thorium and uranuyl ions, microorganisms resistant to thorium and uranium and capable of growing in their presence may produce sequestering agents for these metals in a manner similar to those produced for iron. Such complexation would increase the mobility and bioavailability of thorium and uranium in the environment.Pseudomonas aeruginosa species are resistant to certain heavy metals and have also been found in thorium, uranium and plutonium contaminated areas. In the present work, the ability ofP. aeruginosa to elaborate sequestering agents in medium containing thorium or uranium salts was tested. Addition of 10, 100, and 1,000 ppm of uranium or thorium to culture medium increased the lag period of the organism as the concentration of the metal increased. At concentrations of 1,000 ppm and higher, there was an extended lag period followed by reduction in growth. Uranium has a stronger inhibitory effect on growth of the organism than thorium at similar concentrations. Analyses of the culture media have shown, that relative to the control and under the experimental conditions used, the microorganisms have produced several new chelating agents for thorium and uranium.Some of the bacterially produced compounds resemble, but are not identical to the known iron chelating siderophores isolated from microorganisms, and some of their chemical properties are discussed in this report.

Fate of nutrient enrichment on continental shelves as indicated by the C/N content of bottom sediments

Publisher Summary This chapter discusses the fate of nutrient enrichment on continental shelves as indicated by the C/N content of bottom sediments. The ratio of carbon to nitrogen (C/N) content in most marine organisms is less than six , unlike that of land plants which use more carbohydrates for their support structures and have C/N ratios >15. Detrital particles in the sea also have a C/N ratio greater than 10 as a result of the increased recycling of nitrogen compounds compared to slower decomposition of refractory carbon compounds. Although C/N ratios of >20 can be induced in laboratory cultures of phytoplankton under nitrogen starvation, individual phytoplankton cells are probably not nitrogen limited in the ocean. At close to maximal growth rates, laboratory cultures of phytoplankton have, in fact, C/N ratios

Selectivity in metal uptake by stationary phase microbial populations

In the interaction of metals with the cellular biomass of microorganisms in aqueous solutions, cell wall contituents have been implicated as being responsible for metal binding. Chemical and structural characteristics of cell membranes vary with species and should therefore influence the selective capacity for uptake of different metals by different microorganisms, and thus also influence the behavior of metallic species in the environment. While the rates of uptake of metals by microorganisms have been studied extensively, the comparative capacity for selective uptake of metals by different species of microorganisms under identical experimental conditions has not been studied systematically. To test for this property, cellular biomass derived from eight representative microorganisms has been allowed to interact under similar experimental conditions with acidic solutions of seven heavy metals. The results of these studies show that, in addition to metal selectivity, there is also a species dependent differentiation in the uptake capacity.

On the usefulness of sulfur isotope ratios in crude oil correlations

Sulfur isotope analyses have been completed for twelve samples of marine Jurassic oils from a single basin, and are presented along with previous chemical analyses of the same oils (Seifert and Moldowan, 1978). Two isotopic anomalies are discussed in light of correlational analyses, and show that sulfur isotope ratios, when used with other chemical variables, are sensitive indicators of subtle changes in initial source input. Measurements of δ34S in correlational studies of crude oil characterization and identification are recommended.

Biochemical processing of heavy oils and residuum

During the past several decades, the petroleum industry has adjusted gradually to accommodate the changes in market product demands, government regulations, and the quality and cost of feedstock crude oils. For example, the trends show that the demand for distillate fuels, such as diesel, as compared to gasoline are increasing. Air-quality standards have put additional demand on the processing of heavier and higher sulfur feed stocks. Thus, the 1990 Clean Air Act amendments require the industry to produce greater quantities of oxygenated gasoline, and lower sulfur diesel and reformulated gasoline. Biochemical technology may play an important role in responding to these demands on the petroleum industry. Since oil is of biological origin, some biochemical reactions started at the beginning of its formation are still continuing in reservoirs on a geological time scale. Although these rates are very slow, many reactions can proceed readily under optimal conditions. This article will address some of the reactions that may be useful for processing heavy oils and refinery residuum. 6 refs., 2 figs., 3 tabs.

Geothermal waste treatment biotechnology

Studies at the Brookhaven National Laboratory (BNL) have led to the development of a technically and economically feasible, as well as environmentally acceptable, biochemical process for detoxification of geothermal residues. For this process, selected microorganisms that live in extreme environments have served as models for the new biotechnology. Assuming a 2,500-kg / h sludge production rate, the new technology is capable of a better than 80% removal rate of toxic metals, usually in less than a 25-hour period. The process itself depends on a number of flexible parameters, allowing this technology to be tailored to specific needs of different geothermal producing regimes, such as those found in the Salton Sea and the Geysers area of California. Thus geothermal residual sludges and brines can be processed to remove only a few metals, such as arsenic and mercury, or many metals, ranging from valuable metals such as chromium, gold, and silver to radionuclides, such as radium. In some cases, combined metal removal and metal recovery processes may be cost efficient and therefore advantageous. The emerging biotechnology for the treatment of geothermal energy production wastes is versatile and offers a number of application options, which are discussed in the paper.

The significance of chemical markers in the bioprocessing of fossil fuels

Abstract Biochemical conversion of crude oils is a multi-step process proceeding through a series of biochemical reactions. These reactions can be characterized by a set of chemical markers which are associated with the chemical composition of crude oils. Reactions with heavy crude oils indicate that there is an overall decrease in the concentration and chemical speciation of organic sulfur compounds, and a redistribution of hydrocarbons and organometallic species. The contents of trace metals in the crude oils, such as nickel and vanadium, also decrease. Further, heavy ends of crudes, containing the asphaltenes and the polar nitrogen, sulfur, and oxygen containing fractions, as well as the organometallic compounds and complexes, are biochemically converted to lower molecular weight chemical species. In the studies reported in this paper, microorganisms used to mediate such reactions were thermophilic (> 60°C) and pressure tolerant (up to 2500 psi). These organisms are also capable of biochemical conversion of bituminous and lignite coals in an analogous manner to their action on crude oils and follow similar trends characterized by chemical markers. For example, X-ray absorption near-edge structural (XANES) analyses of biotreated crude oils and low grade coals show that biochemical reactions lead to decreases in organic sulfides and thiophenes with a concurrent increase in sulfoxide contents. Chemically related constituents present in heavy crude oil fractions and low grade coals are the asphaltenes. Asphaltenes are complex structures containing heteroatoms and metals involved in inter- and intra-molecular bridges and stereochemical configurations. The chemical markers associated with the biochemical conversion of oils and coals indicate multiple biochemical processes involving chemical reactions at sites containing heteroatoms and metals leading to a breakdown of the structure(s) to smaller molecular weight units. Thus, using chemical markers as diagnostic tools, the extent and the efficiency of fossil fuel bioconversion may be predicted and monitored, allowing for better cost-efficient field trials. Recent results in this area will be presented and discussed in this paper.

Biodegradation of coals

Abstract Selected strains of bacteria [from the Brookhaven National Laboratory (BNL) collection], capable of degrading heavy crude oils, were used to treat bituminous and lignite coals. Products resulting from biochemical reactions among several microorganisms and different coals were examined by pyrolysis gas chromatography-mass spectrometry (Py. g.c.-m.s.), and X-ray absorption near edge structure (XANES) spectroscopy. The results indicated considerable variations in the organic sulfur as well as modifications in coal structure. Furthermore, biochemical reactions involved in the microbial interactions with coals appeared to be microbial species dependent.