Functional mismatch in a bumble bee pollination mutualism under climate change.

Ecological partnerships, or mutualisms, are globally widespread, sustaining agriculture and biodiversity. Mutualisms evolve through the matching of functional traits between partners, such as tongue length of pollinators and flower tube depth of plants. Long-tongued pollinators specialize on flowers with deep corolla tubes, whereas shorter-tongued pollinators generalize across tube lengths. Losses of functional guilds because of shifts in global climate may disrupt mutualisms and threaten partner species. We found that in two alpine bumble bee species, decreases in tongue length have evolved over 40 years. Co-occurring flowers have not become shallower, nor are small-flowered plants more prolific. We argue that declining floral resources because of warmer summers have favored generalist foraging, leading to a mismatch between shorter-tongued bees and the longer-tubed plants they once pollinated.

Measurement of perchlorate in water by use of an 18O-enriched isotopic standard and ion chromatography with mass spectrometric detection.

Currently, the most promising analytical methodology for low-level determination and confirmation of perchlorate (ClO4-) in drinking water is ion chromatography followed by electrospray ionization mass spectrometric detection (IC-ESI-MS). However, there are still potentially limiting situations that must be considered when analyzing real world samples by IC-ESI-MS. They are: (1) co-elution of contaminants with fragment ions having the same m/z as ClO4-, (2) high background counts at the m/z of interest leading to a subsequent decrease in signal-to-noise, (3) gradual loss of sensitivity occurring over time as the sampling cone and/or ion optics of the mass spectrometer are fouled, and (4) suppression of gas phase ion formation (ionization suppression) that can occur if high concentrations of contaminants co-elute with ClO4-. An internal standard whose response, on the column and in the electrospray, is similar to that of ClO4- would give the highest degree of accuracy possible in situations 3 and 4 listed above. Commercially available NaClO4 that was enriched with oxygen-18 was evaluated for its potential as an internal standard. The level of oxygen-18 (18O) enrichment was verified, the stability of the enriched ClO4- in aqueous solutions was determined, and method performance parameters such as method detection limits, accuracy, precision and ruggedness using the enriched ClO4 as an internal standard were determined. Internal and external calibration yielded similar results with respect to calibration, detection limits, and short-term precision. However, the enriched isotopic internal standard showed superior results with respect to ruggedness and percent recovery of spikes in ground water and synthetic water samples.

Hg reactions in the presence of chlorine species: homogeneous gas phase and heterogeneous gas-solid phase.

The kinetics of Hg chlorination (with HCl) was studied using a flow reactor system with an online Hg analyzer, and speciation sampling using a set of impingers. Kinetic parameters, such as reaction order (alpha), overall rate constant (k'), and activation energy (Ea), were estimated based on the simple overall reaction pathway. The reaction order with respect to C(Hg), k', and Ea were found to be 1.55, 5.07 x 10(-2) exp(-1939.68/T) [(microg/m3)(-055)(s)(-1)]. and 16.13 [kJ/ mol], respectively. The effect of chlorine species (HCl, CH2Cl2) on the in situ Hg capture method previously developed (28) was also investigated. The efficiency of capture of Hg by this in situ method was higher than 98% in the presence of chlorine species. Furthermore, under certain conditions, the presence of chlorine enhanced the removal of elemental Hg by additional gas-phase oxidation.

A mechanistic model for mercury capture with in situ-generated titania particles: role of water vapor.

A mechanistic model to predict the capture of gas-phase mercury (Hg) species using in situ-generated titania nanosize particles activated by UV irradiation is developed. The model is an extension of a recently reported model for photochemical reactions by Almquist and Biswas that accounts for the rates of electron-hole pair generation, the adsorption of the compound to be oxidized, and the adsorption of water vapor. The role of water vapor in the removal efficiency of Hg was investigated to evaluate the rates of Hg oxidation at different water vapor concentrations. As the water vapor concentration is increased, more hydroxy radical species are generated on the surface of the titania particle, increasing the number of active sites for the photooxidation and capture of Hg. At very high water vapor concentrations, competitive adsorption is expected to be important and reduce the number of sites available for photooxidation of Hg. The predictions of the developed phenomenological model agreed well with the measured Hg oxidation rates in this study and with the data on oxidation of organic compounds reported in the literature.

Comparison of nucleic acid extraction and reverse transcription-qPCR approaches for detection of GI and GII noroviruses in drinking water.

The objective of this study was to compare three nucleic acid extraction and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) approaches for norovirus (NoV) detection in drinking water with respect to performance, costs, and analysis time. The approaches evaluated were: (A) an approach that utilizes the QIAamp DNA Blood Mini Kit and multiplex primers and probes for detection; (B) a procedure which includes the NucliSENS Magnetic Extraction Kit and other components of a proposed European Union standard method for NoV detection in foods; and (C) a commercialized assay which uses NucliSENS extraction and Cepheid SmartCycler® technologies. Each approach was evaluated by most probable number (MPN) analysis for detection of GI.1 and GII.4 NoVs from human stool. Furthermore, recoveries of spiked primary effluent in tap water concentrates were compared for each approach. Few significant differences were observed between approaches with regard to performance. However, Approach C was the most time consuming and expensive to perform. This research presents a case study of how molecular-based approaches for detection of NoVs can be compared and how various factors may play a role in which approach laboratories choose to employ.

Analysis of environmental contamination resulting from catastrophic incidents: part 1. Building and sustaining capacity in laboratory networks.

Catastrophic incidents, such as natural disasters, terrorist attacks, and industrial accidents, can occur suddenly and have high impact. However, they often occur at such a low frequency and in unpredictable locations that planning for the management of the consequences of a catastrophe can be difficult. For those catastrophes that result in the release of contaminants, the ability to analyze environmental samples is critical and contributes to the resilience of affected communities. Analyses of environmental samples are needed to make appropriate decisions about the course of action to restore the area affected by the contamination. Environmental samples range from soil, water, and air to vegetation, building materials, and debris. In addition, processes used to decontaminate any of these matrices may also generate wastewater and other materials that require analyses to determine the best course for proper disposal. This paper summarizes activities and programs the United States Environmental Protection Agency (USEPA) has implemented to ensure capability and capacity for the analysis of contaminated environmental samples following catastrophic incidents. USEPA's focus has been on building capability for a wide variety of contaminant classes and on ensuring national laboratory capacity for potential surges in the numbers of samples that could quickly exhaust the resources of local communities. USEPA's efforts have been designed to ensure a strong and resilient laboratory infrastructure in the United States to support communities as they respond to contamination incidents of any magnitude. The efforts include not only addressing technical issues related to the best-available methods for chemical, biological, and radiological contaminants, but also include addressing the challenges of coordination and administration of an efficient and effective response. Laboratory networks designed for responding to large scale contamination incidents can be sustained by applying their resources during incidents of lesser significance, for special projects, and for routine surveillance and monitoring as part of ongoing activities of the environmental laboratory community.

Romancing the salve: Sir Kenelm Digby and the powder of sympathy.

Sir Kenelm Digby's A Late Discourse ... Touching the Cure of Wounds by the Powder of Sympathy (1658) is usually read in the context of seventeenth-century explanations of the weapon-salve. The salve supposedly worked by being applied to the weapon that made a wound rather than to the wound itself. But Digby's essay was as much an effort to claim priority for a powdered version of the sympathetic cure as an explanation of how the cure worked. A close examination of Digby's claims in the Late Discourse in the context of his own earlier work and of works by his contemporaries shows his priority claim to have been false. It was recognized as such by his most knowledgeable associates. The story of Digby's fabrications offers a case study of the generic and rhetorical terms in which seventeenth-century English thinkers made and challenged natural-philosophical claims.

Statistical procedures for determination and verification of minimum reporting levels for drinking water methods.

The United States Environmental Protection Agency's Office of Ground Water and Drinking Water has developed a single-laboratory quantitation procedure: the lowest concentration minimum reporting level (LCMRL). The LCMRL is the lowest true concentration for which future recovery is predicted to fall, with high confidence (99%), between 50% and 150%. The procedure takes into account precision and accuracy. Multiple concentration replicates are processed through the entire analytical method and the data are plotted as measured sample concentration (y-axis) versus true concentration (x-axis). If the data support an assumption of constant variance over the concentration range, an ordinary least-squares regression line is drawn; otherwise, a variance-weighted least-squares regression is used. Prediction interval lines of 99% confidence are drawn about the regression. At the points where the prediction interval lines intersect with data quality objective lines of 50% and 150% recovery, lines are dropped to the x-axis. The higher of the two values is the LCMRL. The LCMRL procedure is flexible because the data quality objectives (50-150%) and the prediction interval confidence (99%) can be varied to suit program needs. The LCMRL determination is performed during method development only. A simpler procedure for verification of data quality objectives at a given minimum reporting level (MRL) is also presented. The verification procedure requires a single set of seven samples taken through the entire method procedure. If the calculated prediction interval is contained within data quality recovery limits (50-150%), the laboratory performance at the MRL is verified.