A5060771568- Microbial Community Ecology and Physiology
- Marine and coastal ecosystems
- Aquatic Ecosystems and Phytoplankton Dynamics
- Photosynthetic Processes and Mechanisms
- Algal biology and biofuel production
- Protist diversity and phylogeny
- Biocrusts and Microbial Ecology
- Genomics and Phylogenetic Studies
- Aquatic Ecosystems and Biodiversity
- Wastewater Treatment and Nitrogen Removal
- Soil and Water Nutrient Dynamics
- bioluminescence and chemiluminescence research
- Environmental DNA in Biodiversity Studies
- Isotope Analysis in Ecology
- Freshwater macroinvertebrate diversity and ecology
- Aquatic Invertebrate Ecology and Behavior
- Fish Ecology and Management Studies
- Photoreceptor and optogenetics research
- Microbial Fuel Cells and Bioremediation
- Bacteriophages and microbial interactions
- Spectroscopy and Quantum Chemical Studies
- Diatoms and Algae Research
- Mitochondrial Function and Pathology
- Polar Research and Ecology
- Plant Stress Responses and Tolerance
Bowling Green State University
2016-2025
Waters (United States)
2021-2024
Bakke Graduate University
2022
Leiden University
2002-2008
Lawrence Berkeley National Laboratory
2006
Unidades Centrales Científico-Técnicas
2001
Consejo Superior de Investigaciones Científicas
2001
University of Wisconsin–Madison
1999
University of Missouri
1985-1989
University of Virginia
1984
Annual cyanobacterial blooms dominated by Microcystis have occurred in western Lake Erie (U.S./Canada) during summer months since 1995. The production of toxins bloom-forming cyanobacteria can lead to drinking water crises, such as the one experienced city Toledo August 2014, when was rendered without for >2 days. It is important understand conditions and environmental cues that were driving this specific bloom provide a scientific framework management future events. To end, samples...
Sandusky Bay experiences annual toxic cyanobacterial blooms dominated by Planktothrix agardhii/suspensa. To further understand the environmental drivers of these events, we evaluated changes in growth response and toxicity Planktothrix-dominated to nutrient amendments with orthophosphate (PO4) inorganic organic forms dissolved nitrogen (N; ammonium (NH4), nitrate (NO3) urea) over bloom season (June - October). We complemented a metagenomic analysis planktonic microbial community. Our results...
ABSTRACT Aerobic biological ammonia oxidation is carried out by two groups of microorganisms, ammonia-oxidizing bacteria (AOB) and the recently discovered archaea (AOA). Here we present a study using cultivation-based methods to investigate differences in growth three AOA cultures one AOB culture enriched from freshwater environments. The strain belong thaumarchaeal group I.1a, with enrichment having highest identity “ Candidatus Nitrosoarchaeum koreensis” strains other representing new...
Blooms of the toxin-producing cyanobacterium Microcystis are increasing globally, leading to loss ecosystem services, threats human health, as well deaths pets and husbandry animals. While nutrient availability is a well-known driver algal biomass, factors controlling “who” present in fresh waters more complicated. possesses multiple strategies adapt temperature, light, changes chemistry, herbivory, parasitism that provide selective advantage over its competitors.
The authors declare no conflicts of interest.
We describe a PCR-based assay designed to detect expression of the phosphonate assimilation gene phnD from picocyanobacteria. The encodes binding protein ABC-type transporter, present in many picocyanobacterial genome sequences. Detection can indicate capacity picoplankton utilize phosphonates, refractory form phosphorus that represent 25% high-molecular-weight dissolved organic pool marine systems. Primer sets were specifically amplify sequences and freshwater Synechococcus spp.,...
Carbon and nutrient cycles in large temperate lakes such as Lake Erie are primarily driven by phototrophic heterotrophic microorganisms, although our understanding of these is often constrained to late spring through summer due logistical constraints. During periods > 90% ice cover February 2008, 2009, 2010, we collected samples from an icebreaker for examination bacterial production well microbial community structure. In comparison with months (August 2002 2010), tested hypotheses...
Mid-winter limnological surveys of Lake Erie captured extremes in ice extent ranging from expansive cover 2010 and 2011 to nearly ice-free waters 2012. Consistent with a warming climate, on the Great Lakes is decline, thus condition encountered may foreshadow lakes future winter state. Here, we show that pronounced changes annual are accompanied by equally important shifts phytoplankton bacterial community structure. Expansive supported blooms filamentous diatoms. By comparison, free...
Ammonia oxidation is the first step of nitrification carried out by ammonia-oxidizing Archaea (AOA) and Bacteria (AOB). Lake Superior Erie are part Great Lakes system differing in trophic status with being oligotrophic meso- to eutrophic. Sediment samples were collected from both lakes used characterize abundance diversity AOA AOB based on ammonia monooxygenase (amoA) gene. Diversity was accessed a pyro-sequencing approach obtained sequences determine phylogeny alpha beta populations. In...
Pseudomonas aeruginosa is a metabolically flexible member of the Gammaproteobacteria. Under anaerobic conditions and presence nitrate, P. can perform (complete) denitrification, respiratory process dissimilatory nitrate reduction to nitrogen gas via nitrite (NO2), nitric oxide (NO) nitrous (N2O). This study focuses on understanding influence environmental bacterial denitrification performance, using mathematical model metabolic network in aeruginosa. To our knowledge, this first for...
Abstract The rediscovery of diatom blooms embedded within and beneath the Lake Erie ice cover (2007–2012) ignited interest in psychrophilic adaptations winter limnology. Subsequent studies determined vital role plays ecophysiology as diatoms partition to underside ice, thereby fixing their location photic zone. Yet, climate change has led widespread decline across Great Lakes, with presenting a nearly “ice-free” state several recent winters. It been hypothesized that resultant turbid,...
Lake Erie algal bloom discussions have historically focused on cyanobacteria, with foundational "blooms like it hot" and "high nutrient" paradigms considered as primary drivers behind cyanobacterial success. Yet, recent surveys rediscovered winter-spring diatom blooms, introducing another key player in the eutrophication story which has been overlooked. These blooms (summer vs. winter) treated solitary events separated by spatial temporal gradients. However, new evidence suggests they may...
Abstract The Winam Gulf (Kenya) is frequently impaired by cyanobacterial harmful algal blooms (cHABs) due to inadequate wastewater treatment and excess agricultural nutrient input. While phytoplankton in Lake Victoria have been characterized using morphological criteria, our aim identify potential toxin‐producing cyanobacteria molecular approaches. was sampled over two successive summer seasons, 16S 18S ribosomal RNA gene sequencing performed. Additionally, key genes involved production of...
The Dps family of proteins are a diverse group bacterial stress-inducible polypeptides that bind DNA and likely confer resistance to peroxide damage during periods oxidative stress long term nutrient limitation. Some members the protein have been shown form large (˜150-kDa), hexameric complexes chromosomal with little sequence specificity. In this paper we report nucleotide dpsA gene from Synechococcus sp. PCC7942 encoding cyanobacterial homolog. deduced amino acid DpsA revealed...
Lake Superior has exhibited a continuous, century‐long increase in nitrate whereas phosphate remains at very low levels. Increasing and led to present‐day severe stoichiometric imbalance; Superior's deepwater NO 3 − :PO 4 3− molar ratio is 10,000, more than 600 times the mean requirement for primary producers. We examine rate of [NO ] relative budgets fixed N. Nitrate continued rise since 1980, though possibly reduced rate. constructed whole‐lake N found that must be generated lake...
Very little is known about the biodiversity of freshwater autotrophic picoplankton (APP) in Laurentian Great Lakes, a system comprising 20% world's lacustrine freshwater. In this study, genetic diversity Lake Superior APP was examined by analyzing 16S rRNA gene and cpcBA PCR amplicons from water samples. By neighbor joining, majority sequences clustered within "picocyanobacterial clade" consisting marine Synechococcus Prochlorococcus. Two new groups spp., pelagic clusters I II, do not group...
Recent discoveries have altered prevailing paradigms concerning the conditions under which nitrification takes place and organisms responsible for in aquatic ecosystems. In Lake Superior, nitrate () concentrations increased fivefold past century. Although previous evidence indicated that most is generated by within lake, important questions remain magnitude controls of nitrification, microbial groups are primarily this process. We measured water‐column rates western basin Superior during...
Ice-nucleating particles (INPs) associated with fresh waters are a neglected, but integral component of the water cycle. Abundant INPs were identified from surface both Maumee River and Lake Erie ice nucleus spectra spanning temperature range −3 to −15 °C. The majority river submicron in size attributed biogenic macromolecules, inferred denaturation ice-nucleation activity by heat. In watershed dominated row-crop agriculture, higher concentrations found samples compared lake samples....