The LTAR Cropland Common Experiment in the Lower Mississippi River Basin.

The Lower Mississippi River Basin Long-Term Agroecosystem Research Site (LMRB-LTAR) encompasses six states from Missouri to the Gulf of Mexico and is coordinated by the USDA-ARS National Sedimentation Laboratory, Oxford, MS. The overarching goal of LTAR is to assess regionally diverse and geographically scalable farming practices for enhanced sustainability of agroecosystem goods and services under changing environment and resource-use conditions. The LMRB-LTAR overall goal is to assess sustainable row crop agricultural production systems that integrate regional environmental and socioeconomic needs.

Salinization and sedimentation drive contrasting assembly mechanisms of planktonic and sediment-bound bacterial communities in agricultural streams.

Agriculture is the most dominant land use globally and is projected to increase in the future to support a growing human population but also threatens ecosystem structure and services. Bacteria mediate numerous biogeochemical pathways within ecosystems. Therefore, identifying linkages between stressors associated with agricultural land use and responses of bacterial diversity is an important step in understanding and improving resource management.

Stream algal biomass response to experimental phosphorus and nitrogen gradients: A case for dual nutrient management in agricultural watersheds.

Watershed managers generally focus on P reduction strategies to combat freshwater eutrophication despite evidence that N co-limits primary production. Our objective was to test the role of P in limiting stream periphyton biomass within the Buffalo River watershed in Arkansas by conducting a 31-d streamside mesocosm experiment. To represent potentially different starting states, cobbles were transplanted from two different tributary streams and initially exposed to a range of P (0, 0.

Mulch-Derived Organic Carbon Stimulates High Denitrification Fluxes from Agricultural Ditch Sediments.

Reactive N is an essential input for healthy, vibrant crop production, yet excess N is often transported off field via agricultural ditches to downstream receiving ecosystems, where it can cause negative impacts to human health, biodiversity loss, as well as eutrophication and resultant hypoxia. Denitrification, the transformation of reactive N to unreactive N gas, within agricultural ditches has potential to reduce impacts to downstream ecosystems but requires substantial organic C substrates. We used a flow-through intact core experiment to test the effects of low-cost management options including a common agricultural amendment, gypsum, and an overlying hardwood mulch layer on promoting denitrification within agricultural ditch sediments.

Diatom Assemblage Changes in Agricultural Alluvial Plain Streams and Application for Nutrient Management.

In large, alluvial floodplains dominated by agriculture, small streams have the potential to experience nutrient enrichment affecting algal assemblage structure and metabolism. Nutrient enrichment is largely driven by application of nutrients and altered hydrologic regimes. To inform stressor-response-based nutrient reduction goals for agricultural alluvial plain streams, diatom assemblages were sampled from 25 streams located within the Mississippi Alluvial Plain (MAP) with various land management practices and associated P and N inputs.

Seasonal Differences in Relationships between Nitrate Concentration and Denitrification Rates in Ditch Sediments Vegetated with Rice Cutgrass.

Increased application of nitrogen (N) fertilizers in agricultural systems contributes to significant environmental impacts, including eutrophication of fresh and coastal waters. Rice cutgrass [ (L.) Sw.

A global database of nitrogen and phosphorus excretion rates of aquatic animals.

Animals can be important in modulating ecosystem-level nutrient cycling, although their importance varies greatly among species and ecosystems. Nutrient cycling rates of individual animals represent valuable data for testing the predictions of important frameworks such as the Metabolic Theory of Ecology (MTE) and ecological stoichiometry (ES). They also represent an important set of functional traits that may reflect both environmental and phylogenetic influences.

Environmental flows in the context of unconventional natural gas development in the Marcellus Shale.

Quantitative flow-ecology relationships are needed to evaluate how water withdrawals for unconventional natural gas development may impact aquatic ecosystems. Addressing this need, we studied current patterns of hydrologic alteration in the Marcellus Shale region and related the estimated flow alteration to fish community measures. We then used these empirical flow-ecology relationships to evaluate alternative surface water withdrawals and environmental flow rules.

Contrasting Nutrient Mitigation and Denitrification Potential of Agricultural Drainage Environments with Different Emergent Aquatic Macrophytes.

Remediation of excess nitrogen (N) in agricultural runoff can be enhanced by establishing wetland vegetation, but the role of denitrification in N removal is not well understood in drainage ditches. We quantified differences in N retention during experimental runoff events followed by stagnant periods in mesocosms planted in three different vegetation treatments: unvegetated, cutgrass [ (L.) Sw.

Thoracolumbar interfascial plane (TLIP) block: a pilot study in volunteers.

Purpose: Regional anesthesia has been shown to improve outcomes in several recent studies. The transversus abdominis plane (TAP) block provides anesthesia to the abdominal wall by introducing local anesthetic to the ventral rami of the thoracolumbar nerves. This work quantifies the area of anesthesia obtained after performing the novel thoracolumbar interfascial plane block (analogous to the TAP block but intended for the back) which targets the sensory component of the dorsal rami of the thoracolumbar nerves.

Influence of drought and total phosphorus on diel pH in wadeable streams: implications for ecological risk assessment of ionizable contaminants.

Climatological influences on site-specific ecohydrology are particularly germane in semiarid regions where instream flows are strongly influenced by effluent discharges. Because many traditional and emerging aquatic contaminants, such as pharmaceuticals, are ionizable, we examined diel surface water pH patterns (i.e.