Defensive and chemical characterization of the froth produced by the cercopid Aphrophora cribrata

Nymphs of the cercopid Aphrophora cribrata cover themselves with a frothy exudate while ingesting sap from their preferred host plant, the eastern white pine, Pinus strobus. Chemical analyses of froth collected from A. cribrata nymphs revealed an array of metabolites belonging to five chemical classes, including fatty acid-derived alcohols, γ-lactones and a single 1-monoacylglycerol, as well as the polyol pinitol and the polyhydroxyalkanoate, poly-3-hydroxybutyrate. Bioassays showed the natural A. cribata froth, as well as a synthetic mixture comprised of representative compound classes identified therein, to be repellent to ants but largely devoid of topical irritancy in tests with cockroaches.     

Using a reverse auction to promote household level stormwater control

Phase II of the US Environmental Protection Agency's (USEPA) National Pollution Discharge Elimination System (NPDES) stormwater regulations requires communities smaller than 100 000 residents to meet new criteria for stormwater runoff reduction. In many cases these smaller communities have no established stormwater utility, and are investigating alternatives for complying with these new, sometimes expensive requirements. We note that it might be cost effective for some communities to encourage homeowners to control stormwater runoff at the parcel level instead of, or in conjunction with more traditional large, infrastructural best management practices (BMP). We go onto argue that in the absence of a strict regulatory cap, an auction is a cost-effective tool for implementing controls on stormwater runoff quantity at the parcel level. In this paper, we test the effectiveness of a procurement auction as the coordinating mechanism for encouraging installation of parcel-scale rain gardens and rain barrels within a small suburban watershed in the Midwest. The auction, which was conducted in spring 2007 and 2008, resulted in installation of 81 gardens and 165 barrels on 107 of the 350 eligible properties. Average cost per liter of runoff detention in both years was $0.36 for gardens and $0.59 for barrels. Interestingly, approximately 55% of the bids were for $0, suggesting that an educational campaign may result in substantial runoff mitigation if utilities paid for the installation of stormwater management practices. However, we found that an auction promoted more participation than education alone and at a cheaper per-unit control cost than a flat stormwater control payment plan. Overall, this study demonstrates that relatively minimal financial incentives can result in homeowners’ willingness-to-accept stormwater management practices on their property, thus opening an important avenue for retrofitting watersheds that are largely in private ownership.     

Experimental and numerical investigation of confined explosion in a blast chamber

An experimental blast program consisting of four tests was conducted in a blast chamber to investigate the effects of cylindrical charges on the peak reflected overpressure and impulse on the wall of the chamber. The charge mass varied from 0.095 kg to 0.2 kg and the standoff distance remained constant at 1.5 m and 1.3 m for the axial and radial directions, respectively. Eight pressure transducers were used in each test to measure the reflected overpressures on confined chamber walls at key locations. A high speed camera was used to record footage of each blast event. The test results indicated that UFC-3-340-02 (Unified Facilities Criteria, 2008) gives a significantly lower prediction for the axially oriented cylindrical charge, and also underestimates the radially oriented cylinder. Another purpose of the blast program was to develop an experimental data set which would validate the AUTODYN model. This would enable the validated AUTODYN model to be used with confidence to generate the overpressure and impulse distribution on a structural element for varying parameters such as the charge shape and charge orientations. Based on the simulated results a new blast model for cylindrical charges has been proposed by considering blast loading on the same level as the charge across the longitudinal direction.     

Seasonal and annual dynamics of harmful algae and algal toxins revealed through weekly monitoring at two coastal ocean sites off southern California, USA

Reports of toxic harmful algal blooms (HABs) attributed to the diatom Pseudo-nitzschia spp. have been increasing in California during the last several decades. Whether this increase can be attributed to enhanced awareness and monitoring or to a dramatic upswing in the development of HAB events remains unresolved. Given these uncertainties, the ability to accurately and rapidly identify an emerging HAB event is of high importance. Monitoring of HAB species and other pertinent chemical/physical parameters at two piers in southern California, Newport and Redondo Beach, was used to investigate the development of a site-specific bloom definition for identifying emerging domoic acid (DA) events. Emphasis was given to abundances of the Pseudo-nitzschia seriata size category of Pseudo-nitzschia due to the prevalence of this size class in the region. P. seriata bloom thresholds were established for each location based on deviations from their respective long-term mean abundances, allowing the identification of major and minor blooms. Sixty-five percent of blooms identified at Newport Beach coincided with measurable DA concentrations, while 36 % of blooms at Redondo Beach coincided with measurable DA. Bloom definitions allowed for increased specificity in multiple regression analysis of environmental forcing factors significant to the presence of DA and P. seriata. The strongest relationship identified was between P. seriata abundances 2 weeks following upwelling events at Newport Beach.     

The chemistry and behaviour of antimony in the soil environment with comparisons to arsenic: A critical review

This article provides a critical review of the environmental chemistry of inorganic antimony (Sb) in soils, comparing and contrasting findings with those of arsenic (As). Characteristics of the Sb soil system are reviewed, with an emphasis on speciation, sorption and phase associations, identifying differences between Sb and As behaviour. Knowledge gaps in environmentally relevant Sb data for soils are identified and discussed in terms of the limitations this imposes on understanding the fate, behaviour and risks associated with Sb in environmental soil systems, with particular reference to mobility and bioavailability.     

Issues in Water Quality Trading: Introduction to Featured Collection1

Heberling, Matthew T., 2011. Issues in Water Quality Trading: Introduction to Featured Collection. Journal of the American Water Resources Association (JAWRA) 47(1):1‐4. DOI: 10.1111/j.1752‐1688.2011.00510.x     

Lichen-based critical loads for atmospheric nitrogen deposition in Western Oregon and Washington Forests, USA

Critical loads (CLs) define maximum atmospheric deposition levels apparently preventative of ecosystem harm. We present first nitrogen CLs for northwestern North America’s maritime forests. Using multiple linear regression, we related epiphytic-macrolichen community composition to: 1) wet deposition from the National Atmospheric Deposition Program, 2) wet, dry, and total N deposition from the Communities Multi-Scale Air Quality model, and 3) ambient particulate N from Interagency Monitoring of Protected Visual Environments (IMPROVE). Sensitive species declines of 20-40% were associated with CLs of 1-4 and 3-9 kg N ha⁻¹ y⁻¹ in wet and total deposition. CLs increased with precipitation across the landscape, presumably from dilution or leaching of depositional N. Tight linear correlation between lichen and IMPROVE data suggests a simple screening tool for CL exceedance in US Class I areas. The total N model replicated several US and European lichen CLs and may therefore be helpful in estimating other temperate-forest lichen CLs.     

Visiting a Climate-Influenced National Park: The Stability of Climate Change Perceptions

Understanding perceptions of global environmental issues, such as climate change, can help inform resource management, policy development, and communication with constituents. Although a considerable amount of research documents citizens’ perceptions of climate change, few have investigated how interactions with climate-impacted parks and protected areas influence these perceptions, and consequently elements of environmental management. Using a mixed methods Instrument Development Approach, the researchers examined the stability of park visitors’ (N = 429) climate change perceptions during a daylong interaction with climate-sensitive and influenced resources at Kenai Fjords National Park in Alaska. Results indicate that global-level beliefs about climate change remained relatively stable during a park experience, but perceptions about climate change at the park-level (e.g., impacts) appeared more malleable. Findings also revealed the type of park experience (terrestrial vs. marine) can influence the degree of change in visitors’ perceptions. Implications for communication, outreach, and park management are discussed.     

Perspectives on Disconnects Between Scientific Information and Management Decisions on Post-fire Recovery in Western US

Environmental regulations frequently mandate the use of “best available” science, but ensuring that it is used in decisions around the use and protection of natural resources is often challenging. In the Western US, this relationship between science and management is at the forefront of post-fire land management decisions. Recent fires, post-fire threats (e.g. flooding, erosion), and the role of fire in ecosystem health combine to make post-fire management highly visible and often controversial. This paper uses post-fire management to present a framework for understanding why disconnects between science and management decisions may occur. We argue that attributes of agencies, such as their political or financial incentives, can limit how effectively science is incorporated into decision-making. At the other end of the spectrum, the lack of synthesis or limited data in science can result in disconnects between science-based analysis of post-fire effects and agency policy and decisions. Disconnects also occur because of the interaction between the attributes of agencies and the attributes of science, such as their different spatial and temporal scales of interest. After offering examples of these disconnects in post-fire treatment, the paper concludes with recommendations to reduce disconnects by improving monitoring, increasing synthesis of scientific findings, and directing social-science research toward identifying and deepening understanding of these disconnects.