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Electrogenic Na-Ca Exchange Clears Ca2+ Loads From Retinal Amacrine Cells In Culture, E. Gleason, S. Borges, M. Wilson Jan 1995

Electrogenic Na-Ca Exchange Clears Ca2+ Loads From Retinal Amacrine Cells In Culture, E. Gleason, S. Borges, M. Wilson

Faculty Publications

Calcium influx into cultured retinal amacrine cells is followed by a small, slow, inward current that we show here results from the operation of electrogenic Na-Ca exchange. The activity of the exchanger is shown to correlate with the magnitude of the Ca2+ load and to depend on both the Ca2+ and Na+ gradients. Li+ is unable to substitute for Na+ and in the absence of Na+, slow tail currents are almost entirely suppressed. A rapid change in [K+](o) does not affect the activity of the exchanger, suggesting that only Na+ and Ca2+ are transported. The ratio of charge entering as …

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Gene Conversion As A Secondary Mechanism Of Short Interspersed Element (Sine) Evolution, David H. Kass, Mark A. Batzer, Prescott L. Deininger Jan 1995

Gene Conversion As A Secondary Mechanism Of Short Interspersed Element (Sine) Evolution, David H. Kass, Mark A. Batzer, Prescott L. Deininger

Faculty Publications

The Alu repetitive family of short interspersed elements (SINEs) in primates can be subdivided into distinct subfamilies by specific diagnostic nucleotide changes. The older subfamilies are generally very abundant, while the younger subfamilies have fewer copies. Some of the youngest Alu elements are absent in the orthologous loci of nonhuman primates, indicative of recent retroposition events, the primary mode of SINE evolution. PCR analysis of one young Alu subfamily (Sb2) member found in the low-density lipoprotein receptor gene apparently revealed the presence of this element in the green monkey, orangutan, gorilla, and chimpanzee genomes, as well as the human genome. …

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Role Of Erythroid Kruppel-Like Factor In Human Γ- To Β-Globin Gene Switching, D. Donze, T. M. Townes, J. J. Bieker Jan 1995

Role Of Erythroid Kruppel-Like Factor In Human Γ- To Β-Globin Gene Switching, D. Donze, T. M. Townes, J. J. Bieker

Faculty Publications

Erythroid Kruppel-like factor (EKLF) is an erythroid-specific transcription factor that contains zinc finger domains similar to the Kruppel protein of Drosophila melanogaster. Previous studies demonstrated that EKLF binds to the CACCC box in the human β-globin gene promoter and activates transcription. CACCC box mutations that cause severe β-thalassemias in humans inhibit EKLF binding. Results described in this paper suggest that EKLF functions predominately in adult erythroid tissue. The EKLF gene is expressed at a 3-fold higher level in adult erythroid tissue than in fetal erythroid tissue, and the EKLF protein binds to the human β-globin promoter 8-fold more efficiently than …

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Seizing Evidence From Suspects For Forensic Analysis, Paul C. Giannelli Jan 1995

Seizing Evidence From Suspects For Forensic Analysis, Paul C. Giannelli

Faculty Publications

No abstract provided.

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Predicting The Effects Of Climate Change On Water Yield And Forest Production In The Northeastern United States, John D. Aber, Scott V. Ollinger, Anthony C. Federer, Peter B. Reich, David W. Kicklighter, Jerry M. Melillo, R. G. Lathrop Jr. Jan 1995

Predicting The Effects Of Climate Change On Water Yield And Forest Production In The Northeastern United States, John D. Aber, Scott V. Ollinger, Anthony C. Federer, Peter B. Reich, David W. Kicklighter, Jerry M. Melillo, R. G. Lathrop Jr.

Faculty Publications

Rapid and simultaneous changes in temperature, precipitation and the atmospheric concentration of CO2 are predicted to occur over the next century. Simple, well-validated models of ecosystem function are required to predict the effects of these changes. This paper describes an improved version of a forest carbon and water balance model (PnET-II) and the application of the model to predict stand- and regional-level effects of changes in temperature, precipitation and atmospheric CO2 concentration. PnET-II is a simple, generalized, monthly time-step model of water and carbon balances (gross and net) driven by nitrogen availability as expressed through foliar N concentration. Improvements from …

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Somatic Embryogenesis And Polyamines In Woody Plants, Rakesh Minocha, Subhash C. Minocha, Liisa Kaarina Simola Jan 1995

Somatic Embryogenesis And Polyamines In Woody Plants, Rakesh Minocha, Subhash C. Minocha, Liisa Kaarina Simola

Faculty Publications

The formation of whole plants from cultured cells is interesting not only because of its applications for mass propagation but also as a prime example of the process of controlled development and differentiation in plants. Cultures capable of producing somatic embryos with high frequency provide ideal experimental systems to study and understand the biochemical basis of hormonal regulation of the developmental process. This knowledge should lead to the planning of media and various treatments that allow us to obtain whole plants from single cells in recalcitrant plant species.

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New Optical Cell Design For Laser Flash Photolysis Studies In Supercritical Fluids, Steven R. Goates, Milton L. Lee, Qin Ji, Edward M. Eyring, Rudi Van Eldik, Kedika Bal Reddy Jan 1995

New Optical Cell Design For Laser Flash Photolysis Studies In Supercritical Fluids, Steven R. Goates, Milton L. Lee, Qin Ji, Edward M. Eyring, Rudi Van Eldik, Kedika Bal Reddy

Faculty Publications

A high-pressure optical cell has been designed that achieves an effective separation between the chemical sample and the pressurizing medium and system. This design limits possible sample contamination and catalytic effects under supercritical fluid sample conditions. Laser flash photolysis experiments were carried out on molybdenum hexacarbonyl dissolved in supercritical CO2. The thermal ring closure reaction of the species Mo(CO)5L, where L is 2,2- bipyridine was found to proceed at rates comparable to those measured previously in liquid benzene or toluene. Much larger activation volumes were found for the reaction in supercritical CO2 than in liquid toluene.

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Country/Region Reports -- United States Of America, Linda A. Malone Jan 1995

Country/Region Reports -- United States Of America, Linda A. Malone

Faculty Publications

No abstract provided.

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Student Evaluations Of Teaching Effectiveness: The Interpretation Of Observational Data And The Principle Of Faute De Mieux, B. Burt Gerstman Jan 1995

Student Evaluations Of Teaching Effectiveness: The Interpretation Of Observational Data And The Principle Of Faute De Mieux, B. Burt Gerstman

Faculty Publications

Student opinion surveys are important but widely misunderstood tools for evaluating teaching effectiveness. In this brief review, an analogy is drawn between the use and interpretation of observational data for public health and biomedical research and the use of student opinion data in evaluating teach ing effectiveness. Sources of systematic error in the form of selection bias, information bias, and confounding are defined and illustrated. Original data concerning intermittent "quid pro quo" confounding (i.e., the effect of expected grades on student evaluations of teaching) are presented. Finally, the principle of faute de mieux ("lack of anything better") and the interpretation …

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Growth Rate As A Function Of Food Consumption In Hatchling Sceloporus Virgatus (Sauria: Iguanidae), Geoffrey R. Smith Jan 1995

Growth Rate As A Function Of Food Consumption In Hatchling Sceloporus Virgatus (Sauria: Iguanidae), Geoffrey R. Smith

Faculty Publications

No abstract provided.

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Book Review Of Principles Of International Environmental Law, Linda A. Malone Jan 1995

Book Review Of Principles Of International Environmental Law, Linda A. Malone

Faculty Publications

No abstract provided.

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Life, Death And Public Policy, Larry I. Palmer Jan 1995

Life, Death And Public Policy, Larry I. Palmer

Faculty Publications

No abstract provided.

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Biblical Evidence For The Universality Of The Genesis Flood, Richard M. Davidson Jan 1995

Biblical Evidence For The Universality Of The Genesis Flood, Richard M. Davidson

Faculty Publications

No abstract provided.

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Em Interaction Of Handset Antennas And A Human In Personal Communications, Michael A. Jensen, Yahya Rahmat-Samii Jan 1995

Em Interaction Of Handset Antennas And A Human In Personal Communications, Michael A. Jensen, Yahya Rahmat-Samii

Faculty Publications

In personal communications, the electromagnetic interaction between handset-mounted antennas and the nearby biological tissue is a key consideration. This paper presents a thorough investigation of this antenna-tissue interaction using the finite-difference time-domain (FDTD) electromagnetic simulation approach with detailed models of real-life antennas on a transceiver handset. The monopole, side-mounted planar inverted F, top-mounted bent inverted F, and back-mounted planar inverted F antennas are selected as representative examples of external and internal configurations. Detailed models of the human head and hand are implemented to investigate the effects of the tissue location and physical model on the antenna performance. Experimental results are …

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African Origin Of Human-Specific Polymorphic Alu Insertions, Mark A. Batzer, Mark Stoneking, Michelle Alegria-Hartman, Hernan Bazan, David H. Kass, Tamim H. Shaikh, Gabriel E. Novick, Panayiotis A. Ioannou, W. Douglas Scheer, Rene J. Herrera, Prescott L. Deininger Dec 1994

African Origin Of Human-Specific Polymorphic Alu Insertions, Mark A. Batzer, Mark Stoneking, Michelle Alegria-Hartman, Hernan Bazan, David H. Kass, Tamim H. Shaikh, Gabriel E. Novick, Panayiotis A. Ioannou, W. Douglas Scheer, Rene J. Herrera, Prescott L. Deininger

Faculty Publications

Alu elements are a family of interspersed repeats that have mobilized throughout primate genomes by retroposition from a few 'master' genes. Among the 500,000 Alu elements in the human genome are members of the human- specific subfamily that are not fixed in the human species; that is, not all chromosomes carry an Alu element at a particular locus. Four such polymorphic human-specific Alu insertions were analyzed by a rapid, PCR-based assay that uses primers that flank the insertion point to determine genotypes based on the presence or absence of the Alu element. These four polymorphic Alu insertions were shown to …

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A Preliminary Mass Balance Model Of Primary Productivity And Dissolved Oxygen In The Mississippi River Plume/Inner Gulf Shelf Region, Victor J. Bierman Jr., Scott C. Hinz, William J. Wiseman Jr., Nancy N. Rabalais, R. Eugene Turner Dec 1994

A Preliminary Mass Balance Model Of Primary Productivity And Dissolved Oxygen In The Mississippi River Plume/Inner Gulf Shelf Region, Victor J. Bierman Jr., Scott C. Hinz, William J. Wiseman Jr., Nancy N. Rabalais, R. Eugene Turner

Faculty Publications

A deterministic, mass balance model for phytoplankton, nutrients, and dissolved oxygen was applied to the Mississippi River Plume/Inner Gulf Shelf (MRP/IGS) region. The model was calibrated to a comprehensive set of field data collected during July 1990 at over 200 sampling stations in the northern Gulf of Mexico. The spatial domain of the model is represented by a three-dimensional, 21-segment water-column .grid extending from the Mississippi River Delta west to the Louisiana-Texas border, and from the shoreline seaward to the 30-60 m bathymetric contours. Diagnostic analyses and numerical experiments were conducted with the calibrated model to better understand the environmental …

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Comparison Of Continuous Records Of Near-Bottom Dissolved Oxygen From The Hypoxia Zone Along The Louisiana Coast, Nancy N. Rabalais, William J. Wiseman, R. Eugene Turner Dec 1994

Comparison Of Continuous Records Of Near-Bottom Dissolved Oxygen From The Hypoxia Zone Along The Louisiana Coast, Nancy N. Rabalais, William J. Wiseman, R. Eugene Turner

Faculty Publications

Oxygen depletion is a seasonally dominant feature of the lower water column on the highly-stratified, riverine-influenced continental shelf of Louisiana. The areal extent of hypoxia (bottom waters ≤2 mg l−1 dissolved oxygen) in mid-summer may encompass up to 9,500 km2, from the Mississippi River delta to the upper Texas coast, with the spatial configuration of the zone varying interannually. We placed two continuously recording oxygen meters (Endeco 1184) within 1 m of the seabed in 20-m water depth at two locations 77 km apart where we previously documented midsummer bottom water hypoxia. The oxygen meters recorded considerably different oxygen conditions …

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Processing Of Song Signals In The Cricket And Its Hormonal Control, Gordon Atkins, John Stout Dec 1994

Processing Of Song Signals In The Cricket And Its Hormonal Control, Gordon Atkins, John Stout

Faculty Publications

SYNOPSIS. Phonotaxis by female crickets to the calling song of males, is an important model for investigating the neural basis of auditory behavior. Recent advances make it possible to explain some components of this behavior and its hormonal control, at the level of identified neurons and molecular expression within those neurons. Tonotopically arranged afferents from the cricket's ear, project to local and intersegmental prothoracic interneurons. Bilateral processing of signals and some temporal-pattern specific processing occurs in the prothoracic ganglion and influences acoustic information that is sent to the brain via ascending interneurons that are demonstrably involved in phonotaxis. High, low …

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Denitrification, Nutrient Regeneration And Carbon Mineralization In Sediments Of Galveston Bay, Texas, Usa, Andrew R. Zimmerman, Ronald Benner Nov 1994

Denitrification, Nutrient Regeneration And Carbon Mineralization In Sediments Of Galveston Bay, Texas, Usa, Andrew R. Zimmerman, Ronald Benner

Faculty Publications

Rates of benthic denitrification, oxygen consumption and nutrient regeneration were measured during winter, spring and summer in Galveston Bay (Texas, USA) sediments. Denitrification ranged from 0 to 47 µmol N2 m-2 h-1 with maximal rates generally occurring in the summer and the upper estuary. Oxygen consumption rates ranged from 38 µmol O2 m-2 h-1 in the winter to 353 µmol O2 m-2 h-1 in the summer and were correlated with denitrification rates. Variations in bay water temperature accounted for 52 % of the variability associated with denitrification rates whereas only 28% …

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Semiclassical Quantization Of A Nonintegrable System: Pushing The Fourier Method Into The Chaotic Regime, Karl Sohlberg, Randall B. Shirts Nov 1994

Semiclassical Quantization Of A Nonintegrable System: Pushing The Fourier Method Into The Chaotic Regime, Karl Sohlberg, Randall B. Shirts

Faculty Publications

Semiclassical Einstein–Brillouin–Keller (EBK) quantization of the nonintegrable Hénon–Heiles Hamiltonian succeeds using the Fourier transform method of Martens and Ezra. Two innovations are required for this success: (1) the use of tunneling corrected quantizing actions obtained from an approximate, one-dimensional Hamiltonian and (2) exploitation of intermediate-time approximate quasiperiodicity or "vague tori'' wherein the Fourier transform of chaotic motion over 10–100 vibrational periods allows the determination of frequencies and amplitudes which approximate motion during the time interval. Approximate tori, actions, and EBK energy levels are then straightforward. We use an interpolation method to smooth over small resonance zones that are not expected …

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Ultrasonic Enhancement Of Antibiotic Action On Gram-Negative Bacteria, William G. Pitt, Michael O. Mcbride, Jared K. Lunceford, Randall J. Roper, Richard D. Sagers Nov 1994

Ultrasonic Enhancement Of Antibiotic Action On Gram-Negative Bacteria, William G. Pitt, Michael O. Mcbride, Jared K. Lunceford, Randall J. Roper, Richard D. Sagers

Faculty Publications

The effect of gentamicin upon planktonic cultures of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, and Staphylococcus aureus was measured with and without application of 67-kHz ultrasonic stimulation. The ultrasound was applied at levels that had no inhibitory or bactericidal activity against the bacteria. Measurements of the MIC and bactericidal activity of gentamicin against planktonic cultures of P. aeruginosa and E. coli demonstrated that simultaneous application of 67-kHz ultrasound enhanced the effectiveness of the antibiotic. A synergistic effect was observed and bacterial viability was reduced several orders of magnitude when gentamicin concentrations and ultrasonic levels which by themselves did not reduce …

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Who Are The Parents Biotechnological Children?, Larry I. Palmer Oct 1994

Who Are The Parents Biotechnological Children?, Larry I. Palmer

Faculty Publications

We do not underestimate the difficulties of legislating on this subject. In addition to the inevitable confrontation with the ethical and moral issues involved, there is the question of the wisdom and effectiveness of regulating a matter so private, yet of such public interest. Legislative consideration of surrogacy may also provide the opportunity to begin to focus on the overall implications of the new reproductive biotechnology- in vitro fertilization, preservation of sperms and eggs, embryo implantation and the like. The problem is how to enjoy the benefits of the technology-especially for infertile couples-while minimizing the risk of abuse. The problem …

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Biochemical And Histological Changes During Ovarian Development Of Cobia, Rachycentron Canadum, From The Northern Gulf Of Mexico, Patricia M. Biesiot, Robert E. Caylor, James S. Franks Oct 1994

Biochemical And Histological Changes During Ovarian Development Of Cobia, Rachycentron Canadum, From The Northern Gulf Of Mexico, Patricia M. Biesiot, Robert E. Caylor, James S. Franks

Faculty Publications

Female cobia, Rachycentron canadum, were sampled on their spawning grounds in the Northern Gulf of Mexico to study changes in proximate analysis (protein, lipid, carbohydrate, and ash) of the ovaries during gonadal maturation. Four major stages of oocyte development were studied: stage 1, previtellogenesis; stage 2, vitellogenesis; stage 3, final maturation; and stage 4, postovulation. Cobia are multiple spawning fish; therefore, ovaries engaged in a sequential round of oogenesis were distinguished as stages 1' and 2'. Protein was the major constituent of cobia ovaries and its contribution of cobia ovaries and its contribution remained fairly constant (49-55% fo the …

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Comparison Of The S Genes And The Biological Properties Of Respiratory And Enteropathogenic Bovine Coronaviruses, X. Zhang, W. Herbst, K. G. Kousoulas, J. Storz Sep 1994

Comparison Of The S Genes And The Biological Properties Of Respiratory And Enteropathogenic Bovine Coronaviruses, X. Zhang, W. Herbst, K. G. Kousoulas, J. Storz

Faculty Publications

The nucleotide sequence of the S gene of the bovine respiratory coronavirus (BRCV) strain G95, which was isolated from nasal swabs of a calf suffering from respiratory disorders, was determined and compared with the S gene of the enteropathogenic bovine coronavirus (BECV) strain LY138. Sequence analysis revealed 98.7% nucleotide and 98.3% deduced amino acid identities between the S genes of BRCV-G95 and BECV-LY138 without any deletions or insertions. Nucleotide substitutions were distributed randomly throughout the gene. Five monoclonal antibodies specific for the S protein distinguished BRCV-G95 from BECV-L9, but failed to differentiate it from BECV-LY138 in Western blots under denatured …

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The Structure And Dynamics Of The Cs2 Molecular Ion, Karl Sohlberg, Chan Yibai Sep 1994

The Structure And Dynamics Of The Cs2 Molecular Ion, Karl Sohlberg, Chan Yibai

Faculty Publications

Several common elementary methods of computing molecular properties, prerequisite to molecular dynamics studies, are tested for their validity for CS+2. Judged sufficiently accurate, these methods are then used to aid in investigating the collisionally activated dissociation of CS+2 upon impact with xenon. Rice–Ramsperger–Kassel–Marcus (RRKM) unimolecular decay rate calculations are presented and compared to experimental studies employing collisional activation. RRKM theory is shown to reproduce the experimental results for collision energies near threshold. When corrected for vibrational anharmonicity, the RRKM calculation shows agreement with the experimental results over a slightly wider range of energies. A discussion is given on the applicability …

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Stature Change In Prehistoric Maya Of The Southern Lowlands, Marie E. Danforth Sep 1994

Stature Change In Prehistoric Maya Of The Southern Lowlands, Marie E. Danforth

Faculty Publications

Since the 1950s, a decline in stature has been offered as evidence of increasing nutritional stress in prehistoric Maya populations, particularly during the Late Classic collapse. A review of the extant skeletal data, however, reveals very inconsistent support for such a decline. The primary explanation for the variation may reside in the small number of skeletal series that have representatives of more than one time period. Other possible explanations include methodological problems associated with stature reconstruction, reliability in sex determination, and variation in health response according to site size and location.

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Global Arrest Of Translation During Invertebrate Quiescence, Gretchen E. Hofmann, Steven C. Hand Aug 1994

Global Arrest Of Translation During Invertebrate Quiescence, Gretchen E. Hofmann, Steven C. Hand

Faculty Publications

Comparing the translational capacities of cell-free systems from aerobically developing embryos of the brine shrimp Artemia franciscana vs. quiescent embryos has revealed a global arrest of protein synthesis. Incorporation rates of [3H]leucine by lysates from 4-h anoxic embryos were 8% of those from aerobic (control) embryos, when assayed at the respective pH values measured for each treatment in vivo. Exposure of embryos to 4 h of aerobic acidosis (elevated CO2 in the presence of oxygen) suppressed protein synthesis to 3% of control values. These latter two experimental treatments promote developmental arrest of Artemia embryos and, concomitantly, cause acute declines in …

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Aging And Exercise: A Health Perspective, Joanna L. Bokovoy, Steven N. Blair Jul 1994

Aging And Exercise: A Health Perspective, Joanna L. Bokovoy, Steven N. Blair

Faculty Publications

Habitual exercise provides protection against fatal coronary heart disease, extends longevity, and enhances quality of life. National surveys show less physical activity in older men and women compared with middle-aged and younger persons; older women are particularly sedentary. Although there are still few longitudinal studies on exercise and physical activity in older individuals, the data support a positive relationship between physical activity and health function in older individuals. The data further show that with regular physical activity, health and fitness are maintained or even increased over time in older individuals. Studies on physical activity requirements for beneficial health effects in …

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Computer Network Resources For Economists, William L. Goffe Jul 1994

Computer Network Resources For Economists, William L. Goffe

Faculty Publications

No abstract provided.

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Activity And Distribution Of Attached Bacteria In Chesapeake Bay, Peter Griffith, Fuh-Kwo Shiah, Kathryn Gloersen, Hugh W. Ducklow, Madilyn Fletcher May 1994

Activity And Distribution Of Attached Bacteria In Chesapeake Bay, Peter Griffith, Fuh-Kwo Shiah, Kathryn Gloersen, Hugh W. Ducklow, Madilyn Fletcher

Faculty Publications

The purpose of this study was to further our understanding of the role of particle-associated bacteria in phytoplankton degradation in the Chesapeake Bay, USA, and to identify environmental parameters that control production by free and particle-associated bacteria. Surface and bottom waters at 10 stations along the length of the Bay were sampled over a 2 yr period. Samples were analyzed for temperature, salinity, chlorophyll, phaeophytin, particulate protein, thymidine incorporation (an estimate of bacterial growth rate), and bacterial total direct counts. Results demonstrated that freeliving bacteria were responsible for most of the total bacterial production, which was correlated with temperature and …

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