A5023744532- Geology and Paleoclimatology Research
- Isotope Analysis in Ecology
- Methane Hydrates and Related Phenomena
- Microbial Community Ecology and Physiology
- Polar Research and Ecology
- Indigenous Studies and Ecology
- Marine and coastal ecosystems
- Climate change and permafrost
- Hydrocarbon exploration and reservoir analysis
- Atmospheric and Environmental Gas Dynamics
- Archaeology and ancient environmental studies
- Nuclear Physics and Applications
- Oceanographic and Atmospheric Processes
- Groundwater and Isotope Geochemistry
- Geological Studies and Exploration
- Atmospheric chemistry and aerosols
- Cryospheric studies and observations
- Pleistocene-Era Hominins and Archaeology
- Oil Spill Detection and Mitigation
- Hydrology and Watershed Management Studies
- Toxic Organic Pollutants Impact
- Air Quality Monitoring and Forecasting
- Reservoir Engineering and Simulation Methods
- Water Quality and Resources Studies
- Fullerene Chemistry and Applications
University of South Carolina
2013-2020
University of South Carolina Sumter
2017-2020
McMaster University
2010-2016
University of California, Irvine
2009-2012
Dalhousie University
2004-2010
Woods Hole Oceanographic Institution
2002
Indiana University Northwest
1997
University of Notre Dame
1997
Environment and Climate Change Canada
1997
Produced on land by incomplete combustion of organic matter, black carbon (BC) enters the ocean aerosol and river deposition. It has been postulated that BC resides in marine dissolved (DOC) pool before sedimentary deposition may attribute to its great 14 C age (1500–6500 years). Here we report first radiocarbon measurements high molecular weight DOC (UDOM). exported from rivers is highly aromatic <500 years old, while open samples contain less have an 18,000 ± 3,000 years. The low...
We report measurements of oceanic black carbon (BC) to determine the sources BC abyssal marine sediments in northeast Pacific Ocean. find that average 14C age is older (by 6200 ± 2200 years) than concurrently deposited non-BC sedimentary organic carbon. investigate aged by measuring a sample sinking particulate (POC) and POC may provide main transport mechanism sediments. suggest incorporated into from combination resuspended sorption ancient dissolved onto POC. Our flux estimate represents...
Quantification of black carbon (BC), carbonaceous material pyrogenic origin, has typically required either chemical or thermal oxidation methods for isolation from heterogeneous matrices, such as sediment soil. The benzene polycarboxylic acid (BPCA) method involves aromatic structures, those in BC, into BPCAs. We revised the BPCA with intent to quantify BC marine dissolved organic (DOC). As part this work, we evaluated mechanism and yield using nine polycyclic hydrocarbons (PAHs) six...
The Keck Carbon Cycle AMS facility at the University of California, Irvine (KCCAMS/UCI) has developed protocols for analyzing radiocarbon in samples as small ∼0.001 mg carbon (C). Mass-balance background corrections modern and 14 C-dead contamination (MC DC, respectively) can be assessed by measuring C-free standards, respectively, using same sample processing techniques that are applied to unknown samples. This approach validated secondary standards similar size C composition Ordinary (such...
The hyperarid core of the Atacama Desert is one driest and most inhospitable places on Earth, where life commonly found in interior rocks (i.e., endolithic habitats). Due to extreme dryness, microbial activity these habitats expected be low; however, rate carbon cycling within communities remains unknown. We address this issue by characterizing isotopic composition ((13)C (14)C) phospholipid fatty acids (PLFA) glycolipid (GLFA) colonized from four different sites inside core. δ(13)C results...
Radiocarbon (14C) is a radioactive isotope that useful for determining the age and cycling of carbon-based materials in Earth system. Compound specific radiocarbon analysis (CSRA) provides powerful insight into turnover individual components make up carbon cycle. Extraneous or nonspecific background (Cex) added during sample processing subsequent isolation CSRA samples. Here, we evaluate quantity signature Cex from two sources: preparative capillary gas chromatography (PCGC, CPCGC) chemical...
Abstract. Extreme environmental conditions such as those found in the polar regions on Earth are thought to test limits of life. Microorganisms living these environments often seek protection from stresses high UV exposure, desiccation and rapid temperature fluctuations, with one protective habitat within rocks. Such endolithic microbial communities, which consist bacteria, fungi, algae lichens, small-scale ecosystems comprised both producers consumers. However, harsh experienced by...
Stormwater detention ponds are widely utilized as control structures to manage runoff during storm events. These also represent biogeochemical hotspots, where carbon (C) and nutrients can be processed buried in sediments. This study quantified C nutrient [nitrogen (N) phosphorus (P)] sources burial rates 14 stormwater representative of typical residential development coastal South Carolina. Bulk sediment accumulation was directly correlated with catchment impervious surface coverage (R2 =...
Cryoconite holes are oases of microbial diversity on ice surfaces. In contrast to the Arctic, where during summer most cryoconite 'open', in Continental Antarctica they often 'lidded' or completely frozen year-round. Thus, represent ideal systems for study community assemblies as well carbon accumulation, since individual can be isolated from external inputs years. Here, we use high-throughput sequencing 16S and 18S rRNA genes describe bacterial eukaryotic compositions surrounding lake,...
We report compound-specific radiocarbon analyses of organic matter in ocean sediments from the northeast Pacific Ocean. Chemical extractions and a preparative capillary gas chromatograph (PCGC) were used to isolate phospholipid fatty acids (PLFA) n -alkanes 3 cores collected off coast California, USA. Mass samples for accelerator mass spectrometry (AMS) 14 C analysis ranged 13–100 μg C. PLFA extracted anaerobic Santa Barbara Basin (595 m depth) had modern Δ values (–20 +54‰), indicating...
Photostabilization of phenosafranin dye on poly(styrenesulfonate)-capped TiO2 nanoparticles has been investigated using diffuse reflectance spectroscopy. The degrades oxidiatively a native surface under visible light excitation as the excited participates in charge injection process. interaction with semiconductor can be significantly reduced by capping particles first poly(styrenesulfonate). increase fluorescence emission and decrease degradation rate increasing polymer suggest protective...
Abstract Currently, there is a lack of understanding on how the magnitude and sources carbon (C) emissions from High Arctic tundra are impacted by changing snow cover duration depth during winter. Here we investigated this issue in graminoid fence experiment shale‐derived gelisols Svalbard end growing season throughout To characterize emissions, measured ecosystem respiration ( R eco ) along with its radiocarbon 14 C) content. We assessed composition soil organic matter (SOM) measuring...
Extraneous carbon (C ex ) added during chemical processing and isolation of black (BC) in environmental matrices was quantified to assess its impact on compound specific radiocarbon analysis (CSRA). is the multiple steps BC extraction, such as incomplete removal solvents, bleed from gas chromatographic cation columns. We use 2 methods evaluate size Δ 14 C values ocean sediments that require additional pretreatment using a column with benzene polycarboxylic acid (BPCA) method. First, direct...
Abstract. Extreme environmental conditions such as those found in the polar regions on Earth are thought to test limits of life. Microorganisms living these environments often seek protection from stresses high UV exposure, desiccation and rapid temperature fluctuations, with one protective habitat within rocks. Such endolithic microbial communities, which consist bacteria, fungi, algae lichens, small-scale ecosystems comprised both producers consumers. However, harsh experienced by...