Sediment Oxygen Demand: A Review of In Situ Methods.

Sediment oxygen demand (SOD) plays a fundamental role in biological and chemical processes within the benthic layer of a water body. Land use, including agricultural land use, can affect SOD. However, a wide variety of approaches have been used for in situ SOD chamber construction and data collection, and modelers frequently use SOD values from the literature, without consideration of the differences in methods.

Long-Term Safety and Efficacy of Minimally Invasive Lumbar Decompression Procedure for the Treatment of Lumbar Spinal Stenosis With Neurogenic Claudication: 2-Year Results of MiDAS ENCORE.

Background And Objectives: This study evaluated the long-term durability of the minimally invasive lumbar decompression (MILD) procedure in terms of functional improvement and pain reduction for patients with lumbar spinal stenosis and neurogenic claudication due to hypertrophic ligamentum flavum. This is a report of 2-year follow-up for MILD study patients.

Methods: This prospective, multicenter, randomized controlled clinical study compared outcomes for 143 patients treated with MILD versus 131 treated with epidural steroid injections.

Effects of food resources on the fatty acid composition, growth and survival of freshwater mussels.

Increased nutrient and sediment loading in rivers have caused observable changes in algal community composition, and thereby, altered the quality and quantity of food resources available to native freshwater mussels. Our objective was to characterize the relationship between nutrient conditions and mussel food quality and examine the effects on fatty acid composition, growth and survival of juvenile mussels. Juvenile Lampsilis cardium and L.

Measuring spatial variation in secondary production and food quality using a common consumer approach in Lake Erie.

Lake Erie is a large lake straddling the border of the USA and Canada that has become increasingly eutrophic in recent years. Eutrophication is particularly focused in the shallow western basin. The western basin of Lake Erie is hydrodynamically similar to a large estuary, with riverine inputs from the Detroit and Maumee Rivers mixing together and creating gradients in chemical and physical conditions.

Human activities cause distinct dissolved organic matter composition across freshwater ecosystems.

Dissolved organic matter (DOM) composition in freshwater ecosystems is influenced by the interactions among physical, chemical, and biological processes that are controlled, at one level, by watershed landscape, hydrology, and their connections. Against this environmental template, humans may strongly influence DOM composition. Yet, we lack a comprehensive understanding of DOM composition variation across freshwater ecosystems differentially affected by human activity.

Fatty acid composition at the base of aquatic food webs is influenced by habitat type and watershed land use.

Spatial variation in food resources strongly influences many aspects of aquatic consumer ecology. Although large-scale controls over spatial variation in many aspects of food resources are well known, others have received little study. Here we investigated variation in the fatty acid (FA) composition of seston and primary consumers within (i.

Rivermouth alteration of agricultural impacts on consumer tissue δ(15)N.

Terrestrial agricultural activities strongly influence riverine nitrogen (N) dynamics, which is reflected in the δ(15)N of riverine consumer tissues. However, processes within aquatic ecosystems also influence consumer tissue δ(15)N. As aquatic processes become more important terrestrial inputs may become a weaker predictor of consumer tissue δ(15)N.

Wetland management reduces sediment and nutrient loading to the upper Mississippi river.

Restored riparian wetlands in the Upper Mississippi River basin have potential to remove sediment and nutrients from tributaries before they flow into the Mississippi River. For 3 yr we calculated retention efficiencies of a marsh complex, which consisted of a restored marsh and an adjacent natural marsh that were connected to Halfway Creek, a small tributary of the Mississippi. We measured sediment, N, and P removal through a mass balance budget approach, N removal through denitrification, and N and P removal through mechanical soil excavation.

Whole-stream response to nitrate loading in three streams draining agricultural landscapes.

Physical, chemical, hydrologic, and biologic factors affecting nitrate (NO3(-)) removal were evaluated in three agricultural streams draining orchard/dairy and row crop settings. Using 3-d "snapshots" during biotically active periods, we estimated reach-level NO3(-) sources, NO3(-) mass balance, in-stream processing (nitrification, denitrification, and NO3(-) uptake), and NO3(-) retention potential associated with surface water transport and ground water discharge. Ground water contributed 5 to 11% to stream discharge along the study reaches and 8 to 42% of gross NO3(-) input.

Effects of pore-water ammonia on in situ survival and growth of juvenile mussels (Lampsilis cardium) in the St. Croix Riverway, Wisconsin, USA.

We conducted a series of in situ tests to evaluate the effects of pore-water ammonia on juvenile Lampsilis cardium in the St. Croix River (WI, USA). Threats to this river and its associated unionid fauna have accelerated in recent years because of its proximity to Minneapolis-St.

Effects of ammonia on juvenile unionid mussels (Lampsilis cardium) in laboratory sediment toxicity tests.

Ammonia is a relatively toxic compound generated in water and sediments by heterotrophic bacteria and accumulates in sediments and pore water. Recent data suggest that unionid mussels are sensitive to un-ionized ammonia (NH3) relative to other organisms. Existing sediment exposure systems are not suitable for ammonia toxicity studies with juvenile unionids; thus, we modified a system to expose juveniles to ammonia that was continuously infused into sediments.