Brenda L. Kirkland

Alternative origins for nannobacteria-like objects in calcite

More than 40 calcite-precipitation experiments were performed under sterile conditions in order to investigate the origins of 25–300 nm spherical-, rod-, and ovoid-shaped objects that have been widely interpreted as evidence of nanometer-scale life (i.e., nannobacteria). Individual experiments included the addition of soluble organic compounds, common species of eubacteria, or phage-induced eubacterial lysates. These experiments indicate that many of the nanometer-scale objects have inorganic or nonnannobacterial origins. In the precipitation experiments, calcite formed euhedral crystals 50–800 nm in diameter and smaller (<50 nm) anhedral or rounded particles or protocrystals. The small anhedral or rounded solids resembled nannobacteria. The relative amount of anhedral or rounded calcite was greatest in experiments with a dissolved organic component. These controlled experiments are in accord with observations that rounded nanometer-scale objects are more common in minerals formed in organic-rich environments. Bacterial fragments occur as rounded to irregularly shaped particles that included cell-wall fragments, expulsed cytoplasm, and relict capsules that also closely resembled nannobacteria. Acid etching of the large euhedral crystals produced in the precipitation experiments also resulted in the formation of nanometer-scale features that resembled nannobacteria in natural carbonates. The shapes of the etching artifacts vary as a function of the strength of the acid and the duration of etching. Much caution is advisable in interpreting the origin of rounded features <50 nm.

Getting to the source: aeolian influx to the Permian Delaware basin region

Abstract Although an aeolian origin for the siliciclastics of the Permian (Guadalupian) Delaware and adjacent basins and shelf has been recognized, their source has remained elusive. An Ancestral Rockies source to the west and northwest has been traditionally favored. We propose instead that these sediments were derived from aeolian systems to the northeast and represented by the Whitehorse Group in the Anadarko Basin. This hypothesis is based upon (1) recognition of the aeolian nature of the Whitehorse, (2) regional correlation of the Whitehorse Group with portions of the Artesia Group, (3) paleoclimatic model-predicted and measured southwestward sediment transport for the Whitehorse, and (4) a proposed transport corridor over emergent mudflats along the northern margins of basisins in the Texas Panhandle and onto the New Mexico shelf. Potentially, a Whitehorse-Artesia link could show the formation of this mixed carbonate/siliciclastic system as the result of the interactions of diverse and distant environmental systems under eustatic and climatic forcing factors.

Electron microscopic and immunological evidence of nanobacterial-like structures in calcified carotid arteries, aortic aneurysms, and cardiac valves

Background: Definitive mechanisms causing vascular calcification are unknown. Experiments were designed to evaluate explanted calcified human vascular tissue for the presence of nanometer-scale objects hypothesized to be a type of bacteria associated with calcified geological specimens and human kidney stones (Folk RL; J Sed Petrology 63:990-999, 1993; Kajander EO, et al., PNAS 95:8274-9279, 1998).

Improvement of Carbon Dioxide Sweep Efficiency by Utilization of Microbial Permeability Profile Modification to Reduce the Amount of Oil Bypassed During Carbon Dioxide Flood

The objective of this project was to couple microbial permeability profile modification (MPPM), with carbon dioxide flooding to improve oil recovery from the Upper Cretaceous Little Creek Oil Field situated in Lincoln and Pike counties, MS. This study determined that MPPM technology, which improves production by utilizing environmentally friendly nutrient solutions to simulate the growth of the indigenous microflora in the most permeable zones of the reservoir thus diverting production to less permeable, previously unswept zones, increased oil production without interfering with the carbon dioxide flooding operation. Laboratory tests determined that no microorganisms were produced in formation waters, but were present in cores. Perhaps the single most significant contribution of this study is the demonstration that microorganisms are active at a formation temperature of 115⁰C (239⁰F) by using a specially designed culturing device. Laboratory tests were employed to simulate the MPPM process by demonstrating that microorganisms could be activated with the resulting production of oil in coreflood tests performed in the presence of carbon dioxide at 66˚C (the highest temperature that could be employed in the coreflood facility). Geological assessment determined significant heterogeneity in the Eutaw Formation, and documented relatively thin, variably-lithified, well-laminated sandstone interbedded with heavily-bioturbated, clay-rich sandstone and shale. Live core samples of the Upper Cretaceous Eutaw Formation from the Heidelberg Field, MS were quantitatively assessed using SEM, and showed that during MPPM permeability modification occurs ubiquitously within pore and throat spaces of 10-20 μm diameter. Testing of the MPPM procedure in the Little Creek Field showed a significant increase in production occurred in two of the five production test wells; furthermore, the decline curve in each of the production wells became noticeably less steep. This project greatly extends the number of oil fields in which MPPM can be implemented.