Implementation of Multi-level Interventions to Mitigate Risk of SARS-CoV-2 Delta Variant at a PUBLIC UNIVERSITY in Southern United States.

During the coronavirus disease 2019 (COVID-19) pandemic, navigating the implementation of public health measures in a politically charged environment for a large state entity was challenging. However, Louisiana State University (LSU) leadership developed and deployed an effective, multi-layered mitigation plan and successfully opened in-person learning while managing cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the fourth surge. We describe the plan to provide a framework for other institutions during this and future responses.

Alterations of endophytic microbial community function in Spartina alterniflora as a result of crude oil exposure.

The 2010 Deepwater Horizon disaster remains one of the largest oil spills in history. This event caused significant damage to coastal ecosystems, the full extent of which has yet to be fully determined. Crude oil contains toxic heavy metals and substances such as polycyclic aromatic hydrocarbons that are detrimental to some microbial species and may be used as food and energy resources by others.

Biodegradation of MC252 polycyclic aromatic hydrocarbons and alkanes in two coastal wetlands.

Complementary microbial and geochemical assessment techniques investigated the biodegradation of PAHs and alkanes in salt marshes impacted by crude oil following the Macondo spill. Contamination was observed in the top 10 cm of the marsh profile based on PAH analysis and measurement of the δC signature of impacted marsh soils. Measurement of evolution of C depleted CO indicated mineralization of crude oil ranging from 2.

Biogeochemical controls on biodegradation of buried oil along a coastal headland beach.

Laboratory experiments investigated oxygen dynamics in buried oiled sands sampled from areas impacted by the Macondo spill. Measured oxygen fluxes in oil deposits that were permeable to tidal water ranged from 10 to 10 μmol/cm-sec, orders of magnitude higher than fluxes in non-permeable deposits (10 to 10 μmol/cm-sec). Oxygen dynamics were well described by 1-d models that represent increased oxygen consumption in oiled sands.

Persisting responses of salt marsh fungal communities to the Deepwater Horizon oil spill.

The plant microbiome, composed of diverse interacting microorganisms, is thought to undergird host integrity and well-being. Though it is well understood that environmental perturbations like oil pollution can alter the diversity and composition of microbiomes, remarkably little is known about how disturbance alters plant-fungal associations. Using Next-Generation sequencing of the 18S rDNA internal transcribed spacer (ITS1) region, we examined outcomes of enduring oil exposure on aboveground leaf and belowground endophytic root and rhizosphere fungal communities of Spartina alterniflora, a highly valued ecosystem engineer in southeastern Louisiana marshes affected by the 2010 Deepwater Horizon accident.

Transport of crude oil and associated microbial populations by washover events on coastal headland beaches.

Storm-driven transport of MC252 oil, sand and shell aggregates was studied on a low-relief coastal headland beach in Louisiana, USA including measurement of alkylated PAHs and Illumina sequencing of intra-aggregate microbial populations. Weathering ratios, constructed from alkylated PAH data, were used to assess loss of 3-ring phenanthrenes and dibenzothiophenes relative to 4-ring chrysenes. Specific aggregate types showed relatively little weathering of 3-ring PAHs referenced to oil sampled near the Macondo wellhead with the exception of certain SRBs sampled from the supratidal environment and samples from deposition areas north of beach.

Distribution, characterization, and exposure of MC252 oil in the supratidal beach environment.

The distribution and characteristics of MC252 oil:sand aggregates, termed surface residue balls (SRBs), were measured on the supratidal beach environment of oil-impacted Fourchon Beach in Louisiana (USA). Probability distributions of 4 variables, surface coverage (%), size of SRBs (mm(2) of projected area), mass of SRBs per m(2) (g/m(2)), and concentrations of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in the SRBs (mg of crude oil component per kg of SRB) were determined using parametric and nonparametric statistical techniques. Surface coverage of SRBs, an operational remedial standard for the beach surface, was a gamma-distributed variable ranging from 0.

Biodegradation of MC252 oil in oil:sand aggregates in a coastal headland beach environment.

Unique oil:sand aggregates, termed surface residue balls (SRBs), were formed on coastal headland beaches along the northern Gulf of Mexico as emulsified MC252 crude oil mixed with sand following the Deepwater Horizon spill event. The objective of this study is to assess the biodegradation potential of crude oil components in these aggregates using multiple lines of evidence on a heavily-impacted coastal headland beach in Louisiana, USA. SRBs were sampled over a 19-month period on the supratidal beach environment with reasonable control over and knowledge of the residence time of the aggregates on the beach surface.

Biogeochemical characterization of MC252 oil:sand aggregates on a coastal headland beach.

MC252 oil:sand aggregates, termed surface residue balls (SRBs), were sampled for physical, chemical and microbial characteristics from different tidal zones on a coastal headland beach in Louisiana, USA. Supratidal SRBs were smaller, had low moisture content, and salinities that were <2 ppt. Intertidal SRBs were hypersaline and had higher N and sulfate concentrations, consistent with regular tidal inundation.

Air quality during demolition and recovery activities in post-Katrina New Orleans.

Air samples were collected during demolition and cleanup operations in the Lakeview district of New Orleans, Louisiana, USA, in late 2005 during the period immediately after Hurricane Katrina. Three different high-volume air samples were collected around waste collection areas that were created to temporarily hold the debris from the cleanup of residential properties in the area. Particulate concentrations were elevated and included crystalline fibers associated with asbestos.

Reduction of trichloroethylene and nitrate by zero-valent iron with peat.

The feasibility of using zero-valent iron (ZVI) and peat mixture as in situ barriers for contaminated sediments and groundwater was investigated. Trichloroethylene (TCE) and nitrate (NO(3)(-)), redox sensitive contaminants were reduced by ZVI and peat soil mixture under anaerobic condition. Peat was used to support the sorption of TCE, microbial activity for biodegradation of TCE and denitrification while TCE and nitrate were reduced by ZVI.

Effect of competitive terminal electron acceptor processes on dechlorination of cis-1,2-dichloroethene and 1,2-dichloroethane in constructed wetland soils.

Thermodynamic calculations were coupled with time-series measurements of chemical species (parent and daughter chlorinated solvents, H(2), sulfite, sulfate and methane) to predict the anaerobic transformation of cis-1,2-dichloroethene (cis-1,2-DCE) and 1,2-dichloroethane (1,2-DCA) in constructed wetland soil microcosms inoculated with a dehalorespiring culture. For cis-1,2-DCE, dechlorination occurred simultaneously with sulfite and sulfate reduction but competitive exclusion of methanogenesis was observed due to the rapid H(2) drawdown by the dehalorespiring bacteria. Rates of cis-1,2-DCE dechlorination decreased proportionally to the free energy yield of the competing electron acceptor and proportionally to the rate of H(2) drawdown, suggesting that H(2) competition between dehalorespirers and other populations was occurring, affecting the dechlorination rate.

Wetland plant uptake of desorption-resistant organic compounds from sediments.

Wetland plant uptake of 14C-labeled phenanthrene and chlorobenzene was investigated in greenhouse studies using sediment prepared to contain only the desorption-resistant fraction of the contaminant. Measurements of contaminant distribution in the plants and root-contaminant partition coefficients were conducted as well as estimates of the transpiration stream concentration of chlorobenzene and phenanthrene. Plant uptake of desorption-resistant phenanthrene and chlorobenzene occurred primarily in the root zone with total uptake ranging from 3.

Application of a dialysis sampler to monitor phytoremediation processes.

A cylindrical dialysis sampler (1.2 m in length; 5 cm in diameter) was designed and constructed to sample small-scale phytoremediation processes in the root zone of poplar trees. The study site was a 183-tree plantation of hybrid poplars located at Aberdeen Proving Ground, Maryland, at the J-Field Area of Concern.

Fate of perchlorate-contaminated water in upflow wetlands.

The potential of natural wetland systems to treat perchlorate-contaminated water was investigated in vertical upflow wetland columns planted with and without Bulrush (Scirpus sp.). In the absence of nitrate (NO3- -N <1mg/L), wetland columns were capable of removing ClO4- to levels below the detection limit (<4 microg/L) for a series of influent ClO4- (4, 8, 16, and 32 mg/L).

Hydrogen thresholds as indicators of dehalorespiration in constructed treatment wetlands.

Anaerobic degradation of cis-1,2-dichloroethene (cis-1,2-DCE) and 1,2-dichloroethane (1,2-DCA) was studied in microcosms derived from a laboratory-scale upflow treatment wetland system used to biodegrade chlorinated compounds present in groundwater from a Superfund site. Dechlorination kinetics of cis-1,2-DCE (0.94-1.

Mineralization of desorption-resistant 1,4-dichlorobenzene in wetland soils.

Laboratory studies were conducted to investigate the biologically mediated, aerobic mineralization of both freshly added and artificially aged, desorption-resistant 1,4-dichlorobenzene (1,4-DCB). The adsorption and desorption of 1,4-DCB isotherms were established in three wetland soils using decant-refill batch techniques. Significant nonlinearity and hysteresis were observed in the isotherms with a hysteresis index ranging from 0.

Effect of sorption and desorption resistance on aerobic trichloroethylene biodegradation in soils.

Biodegradation of trichloroethylene (TCE) by toluene-degrading bacteria was measured under aerobic conditions in aqueous and soil-slurry batch microcosms. For soil-phase experiments, a freshly contaminated soil and a soil containing only the desorption-resistant fraction of TCE were tested. In both cases, presence of soil resulted in biodegradation rates substantially lower than those determined in the absence of soil.