Spatial patterns of enzymatic activity in large water bodies: Ship-borne measurements of beta-D-glucuronidase activity as a rapid indicator of microbial water quality.

This study used automated enzymatic activity measurements conducted from a mobile research vessel to detect the spatial variability of beta‑d‑glucuronidase (GLUC) activity in large freshwater bodies. The ship-borne observations provided the first high-resolution spatial data of GLUC activity in large water bodies as rapid indication of fecal pollution and were used to identify associations with hydrological conditions and land use. The utility of this novel approach for water quality screening was evaluated by surveys of the Columbia River, the Mississippi River and the Yahara Lakes, covering up to a 500 km river course and 50 km lake area.

Methane in groundwater from a leaking gas well, Piceance Basin, Colorado, USA.

Site-specific and regional analysis of time-series hydrologic and geochemical data collected from 15 monitoring wells in the Piceance Basin indicated that a leaking gas well contaminated shallow groundwater with thermogenic methane. The gas well was drilled in 1956 and plugged and abandoned in 1990. Chemical and isotopic data showed the thermogenic methane was not from mixing of gas-rich formation water with shallow groundwater or natural migration of a free-gas phase.

Controls on methane concentrations and fluxes in streams draining human-dominated landscapes.

Streams and rivers are active processors of carbon, leading to significant emissions of CO and possibly CH to the atmosphere. Patterns and controls of CH in fluvial ecosystems remain relatively poorly understood. Furthermore, little is known regarding how major human impacts to fluvial ecosystems may be transforming their role as CH producers and emitters.

High-speed limnology: using advanced sensors to investigate spatial variability in biogeochemistry and hydrology.

Advanced sensor technology is widely used in aquatic monitoring and research. Most applications focus on temporal variability, whereas spatial variability has been challenging to document. We assess the capability of water chemistry sensors embedded in a high-speed water intake system to document spatial variability.

Ebullitive methane emissions from oxygenated wetland streams.

Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection.

A natural history of melanomas and dysplastic nevi: an atlas of lesions in melanoma-prone families.

Background: Few long-term clinical and histologic data for melanocytic lesions have been available based on the mutation status of families at an increased risk of melanoma. In the current study, the authors describe the clinical and histologic features of dysplastic nevi and melanoma over time in families at an increased risk of melanoma with differing germline mutations in CDKN2A, CDK4, or not yet identified genes.

Methods: Thirty-three families with > 2 living members with invasive melanoma were evaluated clinically and followed prospectively for up to 25 years.