LANDSCAPE ATTRIBUTES AS CONTROLS ON GROITHD WATER NITRATE REMOVAL CAPACITY OF RIPARIAN ZONES1

ABSTRACT: Inherent site factors can generate substantial variation in the ground water nitrate removal capacity of riparian zones. This paper examines research in the glaciated Northeast to relate variability in ground water nitrate removal to site attributes depicted in readily available spatial databases, such as SSUIRGO. Linking site‐specific studies of riparian ground water nitrate removal to spatial data can help target high‐value riparian locations for restoration or protection and improve the modeling of watershed nitrogen flux. Site attributes, such as hydric soil status (soil wetness) and geomorphology, affect the interaction of nitrate‐enriched ground water with portions of the soil ecosystem possessing elevated biogeochemical transformation rates (i.e., biologically active zones). At our riparian sites, high ground water nitrate‐N removal rates were restricted to hydric soils. Geomorphology provided insights into ground water flowpaths. Riparian sites located on outwash and organic/alluvial deposits have high potential for nitrate‐enriched ground water to interact with biologically active zones. In till deposits, ground water nitrate removal capacity may be limited by the high occurrence of surface seeps that markedly reduce the time available for biological transformations to occur within the riparian zone. To fully realize the value of riparian zones for nitrate retention, landscape controls of riparian nitrate removal in different climatic and physiographic regions must be determined and translated into available spatial databases.     

Groundwater Denitrification Capacity of Riparian Zones in Suburban and Agricultural Watersheds1

Watson, Tara K., Dorothy Q. Kellogg, Kelly Addy, Arthur J. Gold, Mark H. Stolt, Sean W. Donohue, and Peter M. Groffman, 2010. Groundwater Denitrification Capacity of Riparian Zones in Suburban and Agricultural Watersheds. Journal of the American Water Resources Association (JAWRA) 46(2):237-245. DOI: 10.1111/j.1752-1688.2010.00418.x Abstract: We evaluated the relationship of dominant watershed land use to the structure and nitrogen (N) sink function of riparian zones. We focused on groundwater denitrification capacity, water table dynamics, and the presence and pattern of organically enriched deposits. We used the push-pull method (measurement of ¹⁵N-enriched denitrification gases derived from an introduced groundwater plume of ¹⁵N-enriched nitrate) to evaluate groundwater denitrification capacity on nine forested wetland riparian sites developed in alluvial or outwash parent materials in southern New England. Three replicate sites were located in each of the three watershed types, those with substantial (1) irrigated agriculture, (2) suburban development, and (3) forest. Soil morphology and water table dynamics were assessed at each site. We found significantly lower mean annual water tables at sites within watersheds with substantial irrigated agriculture or suburban development than forested watersheds. Water table dynamics were more variable at sites within suburban watersheds, especially during the summer. Groundwater denitrification capacity was significantly greater at sites within forested watersheds than in watersheds with substantial irrigated agriculture. Because of the high degree of variability observed in riparian sites within suburban watersheds, groundwater denitrification capacity was not significantly different from either forested or agricultural watersheds. The highly variable patterns of organically enriched deposits and water tables at sites within suburban watersheds suggests that depositional events are irregular, limiting the predictability of groundwater N dynamics in these riparian zones. The variability of riparian N removal in watersheds with extensive suburbia or irrigated agriculture argues for N management strategies emphasizing effective N source controls in these settings.     

Optimizing Human Intestinal Enteroids for Environmental Monitoring of Human Norovirus

Human noroviruses (HuNoV) are the leading cause of gastrointestinal illness and environmental monitoring is crucial to prevent HuNoV outbreaks. The recent development of a HuNoV cell culture assay in human intestinal enteroids (HIEs) has enabled detection of infectious HuNoV. However, this complex approach requires adaptation of HIEs to facilitate HuNoV replication from environmental matrixes. Integrating data from 200 experiments, we examined six variables: HIE age, HIE basement membrane compounds (BMC), HuNoV inoculum processing, HuNoV inoculum volume, treatment of data below limit of detection (LOD), and cutoff criteria for determining positive HuNoV growth. We infected HIEs with HuNoV GII.4 Sydney positive stool and determined 1.4 × 10³ genome equivalents per HIE well were required for HuNoV replication. HIE age had minimal effect on assay outcomes. LOD replacement and cutoff affected data interpretation, with lower values resulting in higher estimated HuNoV detection. Higher inoculum volumes lead to minimal decreases in HuNoV growth, with an optimal volume of 250uL facilitating capture of low concentrations of HuNoVs present in environmental isolates. Processing of HuNoV inoculum is valuable for disinfection studies and concentrating samples but is not necessary for all HIE applications. This work enhances the HuNoV HIE cell culture approach for environmental monitoring. Future HIE research should report cell age as days of growth and should clearly describe BMC choice, LOD handling, and positive cutoff.

     

What do consumers believe about future gasoline prices?

A full understanding of how gasoline prices affect consumer behavior frequently requires information on how consumers forecast future gasoline prices. We provide the first evidence on the nature of these forecasts by analyzing two decades of data on gasoline price expectations from the Michigan Survey of Consumers. We find that average consumer beliefs are typically indistinguishable from a no-change forecast, justifying an assumption commonly made in the literature on consumer valuation of energy efficiency. We also provide evidence on circumstances in which consumer forecasts are likely to deviate from no-change and on significant cross-consumer forecast heterogeneity.     

Thermal Inactivation of Human Norovirus Surrogates

We investigated the thermal inactivation profiles of murine norovirus (MNV), Hepatitis A virus (HAV), and feline calicivirus (FCV), which are surrogates for the study of human noroviruses. Thermal inactivation of MNV and FCV were evaluated at 37, 50, and 60°C and HAV at 37, 50, 60, and 70°C. All viral surrogates were relatively stable at 37°C. MNV and FCV decimal reduction times (D-values) at 50°C were statistically significantly different (P < 0.05) with MNV being more stable. Both surrogates had comparable, low D-values at 60°C. HAV had significantly higher (P < 0.05) D-values than both MNV and FCV at 50 and 60°C. Overall, the infectivity assay results indicate that HAV is resistant to thermal inactivation while MNV is moderately resistant and FCV is least resistant.     

Community-based Organizations and Neighbourhood Environmental Problem Solving: A Framework for Adoption of Information Technologies

Community-based organizations (CBOs) today seek improved capacity to address environmental problems in urban neighbourhoods. Many seek access to information technologies such as the Internet and Geographic Information Systems (GIS) to expand information about their neighbourhood's environmental quality to support their planning and service efforts. Experience with the Internet has been bolstered somewhat by programmesto create community networks. This experience and experience with GIS in planning at the municipal and state levels reveals a set of technical, organizational and personal prerequisites that bolster successful and effective adoption of information technologies. This paper reviews these prerequisites as they pertain to CBOs and makes recommendations for transactions that could enhance CBO adoption of the Internet and GIS to address environmental problems in urban neighbourhoods. The paper concludes that a constellation of prerequisite conditions, most predominantly data availability problems, staff skill acquisition and staff retention problems, offer the greatest challenges for CBOs seeking to adopt information technologies to manage environmental problems more effectively.     

Ohio's Balanced Growth Program: a case study of collaboration for planning and policy design

This paper describes the collaborative planning process for a new landscape planning programme in Ohio that seeks to influence land urbanisation patterns through joint local land use decision making on a watershed basis. The programme was developed through a collaborative process by a state agency-appointed task force that included agency staff and a wide range of stakeholders. The paper describes the process in terms of the collaborative mechanisms, the participants, the programmatic outputs, and the social and organisational outcomes that set the foundation for enhanced watershed quality through better land use decision-making practices. Key collaborations formed during the process were inter-agency collaborations, a non-profit organisation that partnered with the agencies, and that of state agencies with local governments to develop watershed-based land use plans. A most critical outcome was creation of a learning community, through an exploratory research process that used multiple methods of data gathering and consensus-building deliberation. The paper is based on a review of published documents and plans, meeting minutes, participant observation of committee and workgroup meetings and interactive research.     

A Regional Analysis of Lake Acidification Trends for the Northeastern U.S., 1982-1994

Acidic deposition is a regional phenomenon, but its effects have traditionally been studied using site-specific, intensive monitoring. We present trends information for 36 lakes of high-to-moderate acid sensitivity (defined as acid neutralizing capacity [ANC] < 100 eq L-1), and 15 deposition monitoring stations, in the northeastern U.S. for the period 1982-1994. Trends at each site were assessed through use of the Seasonal Kendall tau test; the resulting statistics were combined, through a technique analogous to analysis of variance, to produce quasi-regional estimates of change for key chemical variables. Rates of sulfate deposition declined significantly across all of the northeastern region during this time period, while rates of nitrate and ammonium deposition were unchanged. All lakes exhibited strong decreases in sulfate concentrations in response to declining sulfate deposition, but there was a strong contrast in the response of acid/base status between lakes in New England and lakes in the Adirondacks. As a group, the New England lakes exhibited recovery (ANC = +0.8 eq L-1yr-1, p<0.001), while the Adirondack lakes exhibited either no trend or further acidification (as a group, ANC = -0.5 eq L-1yr-1, p<0.01). This contrast can be attributed to changes in base cation concentrations: New England lakes exhibited base cations declines that were smaller in magnitude than declines in sulfate, producing the observed recovery in ANC; Adirondack lakes showed base cation declines that were very similar to those of sulfate, and no recovery was evident.     

Claw allometry in green crabs, Carcinus maenas: heterochely, handedness, and sex

Claw loss and reversal of handedness during regeneration are common phenomena in heterochelous decapod crustaceans, which typically have one large ‘crusher’ claw on the right side and a smaller ‘cutter’ claw on the left. Little is known about the relative importance of claw growth vs. body growth during claw regeneration. Here the relationship between claw size and body size of green crabs, Carcinus maenas, was examined to test for differences in claw allometry as a function of handedness and sex, as there are differences in how males and females use their claws. A total of 730 crabs (range = 15.7–83.6 mm CW) were collected from Maine to New Jersey, USA from May to October 1997, 2000, and 2004–2005. Claw growth, particularly crushers, was accelerated in left-handed crabs and in males compared to right-handed crabs and females respectively. These differing growth strategies highlight the role of sexual dimorphism in claw usage and the importance of achieving heterochely after claw injury. These results imply that handedness should be an important factor to consider in future studies of crab morphology, behavior, and morphometrics. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.