Deuterium marking of chemical emissions: detectability and fitness consequences of a novel technique for insect behavioural studies

Behavioural studies often need to employ marking techniques to identify and track individuals. Marks ideally have no influence on behaviour or fitness of marked individuals or on the organisms with which they interact. A newly developed internal marking technique uses deuterium to manipulate the chemical emissions of bethylid wasps that are parasitoids of lepidopteran larvae. Wasps are deuterated indirectly by injecting deuterium oxide (heavy water) into the host on which they feed as larvae. Adult wasps emit a volatile chemical under stressful conditions and the emissions of deuterated and undeuterated wasps can be clearly and readily distinguished by measuring the ratio of deuterated/undeuterated molecules using real‐time mass spectrometry. Deuterated female wasps are, however, detectably disadvantaged in dyadic contests for host resources, a component of female fitness. In this study, we evaluated potential side‐effects of this deuterium marking technique on three further correlates of female Goniozus legneri Gordh (Hymenoptera: Bethylidae) fitness: longevity, lifetime fecundity, and offspring developmental mortality. We found that deuterium enrichment has no overall adverse effects on these parameters. We further showed that injecting hosts with different concentrations of deuterium results in distinguishably different volatile emissions of adult wasps, such that at least three individuals can be simultaneously identified by their chemical signatures. We also showed that deuterium marking remains effective beyond a wasp's death: deuterated and undeuterated wasps remain readily distinguishable after storage. We discuss potential applications of deuterium marking for the laboratory and field study of chemical communication, dispersal, and mating structure in parasitoid wasps and other insects.     

Limnology of the Green Lakes Valley: phytoplankton ecology and dissolved organic matter biogeochemistry at a long-term ecological research site

ABSTRACT

Background: Surface waters are the lowest points in the landscape, and therefore serve as excellent integrators and indicators of changes taking place in the surrounding terrestrial and atmospheric environment.

Aims: Here we synthesise the findings of limnological studies conducted during the past 15 years in streams and lakes in the Green Lakes Valley, which is part of the Niwot Ridge Long Term Ecological Research (LTER) Site.

Methods: The importance of these studies is discussed in the context of aquatic ecosystems as indicators, integrators, and regulators of environmental change. Specifically, investigations into climatic, hydrologic, and nutrient controls on present-day phytoplankton, and historical diatom, community composition in the alpine lake, Green Lake 4, are reviewed. In addition, studies of spatial and temporal patterns in dissolved organic matter (DOM) biogeochemistry and reactive transport modelling that have taken place in the Green Lakes Valley are highlighted.

Results and conclusions: The findings of these studies identify specific shifts in algal community composition and DOM biogeochemistry that are indicative of changing environmental conditions and provide a framework for detecting future environmental change in the Green Lakes Valley and in other alpine watersheds. Moreover, the studies summarised here demonstrate the importance of long-term monitoring programmes such as the LTER programme.     

Can we produce carbon and climate neutral forest bioenergy?

Harvesting branches, stumps and unmercantable tops, in addition to stem wood, decreases the carbon input to the soil and consequently reduces the forest carbon stock. We examine the changes in the forest carbon cycle that would compensate for this carbon loss over a rotation period and lead to carbon neutral forest residue bioenergy systems. In addition, we analyse the potential climate impact of these carbon neutral systems. In a boreal forest, the carbon loss was compensated for with a 10% increase in tree growth or a postponing of final felling for 20 years from 90 to 110 years in one forest rotation period. However, these changes in carbon sequestration did not prevent soil carbon loss. To recover soil carbon stock, a 38% increase in tree growth or a 21% decrease in the decomposition rate of the remaining organic matter was needed. All the forest residue bioenergy scenarios studied had a warming impact on climate for at least 62 years. Nevertheless, the increases in the carbon sequestration from forest growth or reduction in the decomposition rate of the remaining organic matter resulted in a 50% smaller warming impact of forest bioenergy use or even a cooling climate impact in the long term. The study shows that carbon neutral forest residue bioenergy systems have warming climate impacts. Minimization of the forest carbon loss improves the climate impact of forest bioenergy.     

Energy Cost of Living and Associated Pollution for Beijing Residents

China's remarkable economic growth in the last 3 decades has brought about big improvements in quality of life while simultaneously contributing to serious environmental problems. The aim of all economic activities is, ultimately, to provide the population with products and services. Analyzing environmental impacts of consumption can be valuable for illuminating underlying drivers for energy use and emissions in society. This study applies an environmentally extended input‐output analysis to estimate household environmental impact (HEI) of urban Beijing households at different levels of development. The analysis covers direct and indirect energy use and emissions of carbon dioxide (CO₂), sulfur dioxide (SO₂), and nitrogen oxide (NO_x). On the basis of observations of how HEI varies across income groups, prospects for near‐future changes in HEI are discussed. Results indicate that in 2007, an urban resident in Beijing used, on average, 52 gigajoules of total primary energy supply. The corresponding annual emissions were 4.2 tonnes CO₂, 27 kilograms SO₂, and 17 kilograms NO_x. Of this, only 18% to 34% was used or emitted by the households directly. While the overall expenditure elasticity of energy use is around 0.9, there is a higher elasticity of energy use associated with transport. The results suggest that significant growth in HEI can be expected in the near future, even with substantial energy efficiency improvements.     

An automated screening method for drugs and toxic compounds in human serum and urine using liquid chromatography–tandem mass spectrometry

A fully automated screening using liquid chromatography–mass spectrometric method applying data-dependent acquisition was developed to identify toxicologically relevant substances in serum and urine. A library including more than 405 spectra of about 365 compounds (main drugs and important metabolites) was established. An easy to use program was created to automate and accelerate library search. Drugs were identified based on their relative retention times, molecular ions and fragment ions. Limits of detection were tested with 100 of the 365 compounds the majority of these were lower than 100 μg/l (67%). The developed LC–MS–MS system seems to be a valuable alternative to other general unknown screening methods allowing fast and specific identification of drugs in serum and urine samples.     

大气汞源解析受体模型研究进展

大气汞循环演化对全球汞的生物地球化学循环起着极其重要的作用。人为活动(化石燃料燃烧、水泥生产、氯碱制造以及金属冶炼与加工等)已成为大气汞的重要来源。在一定条件下,大气中的汞会发生干湿沉降而对某一局部环境——受体产生很大的影响。大气汞沉降在城市和工业区呈现出很强的空间梯度现象,排放源附近的汞沉降量明显较强。利用对受体的研究开展大气汞的源解析工作,是大气汞研究的一个重要领域。本文综述了污染物源解析的受体模型的研究及应用,介绍了化学质量平衡法、因子分析法、正交矩阵因子分解法、多元线性回归法等方法,概括了源解析在大气汞方面的应用成果,对我国区域大气汞源解析受体模型的建立及应用进行了探讨。     

Seasonal ultrasonic acoustic emissions of <Emphasis Type="Italic">Quercus ilex</Emphasis> L. trees in a Mediterranean forest

Ultrasonic acoustic emissions were measured in Quercus ilex trees of a Mediterranean forest in Catalonia (NE Spain) each season from summer of 2004 to autumn of 2005. Acoustic emissions were maximum during hot and dry summer periods. Acoustic emissions started below 17% soil moisture, 0.85 RWC, and 2.5 MPa leaf water potential. They were negatively correlated with soil moisture and leaf water potential. The relationship between acoustic emissions and leaf water potential was the strongest, indicating that xylem tension is the most important factor inducing both cavitation (acoustic emissions) and a decrease in leaf water potential. Future increase of xylem cavitation derived from climate change may result in growth and survival limitations for this species in the drier southern limits of its current distribution.     

To what extent do current and projected increases in surface ozone affect photosynthesis and stomatal conductance of trees? A meta‐analytic review of the last 3 decades of experiments

The surface concentration of ozone ([O(3)]) has risen from less than 10 ppb prior to the industrial revolution to a day-time mean concentration of approximately 40 ppb over much of the northern temperate zone. If current global emission trends continue, surface [O(3)] is projected to rise a further 50% over this century, with larger increases in many locations including Northern Hemisphere forests. This review uses statistical meta-analysis to determine mean effects, and their confidence limits, of both the current and projected elevations of [O(3)] on light-saturated photosynthetic CO(2) uptake (A(sat)) and stomatal conductance (g(s)) in trees. In total, 348 measurements of A(sat) from 61 studies and 266 measures of g(s) from 55 studies were reviewed. Results suggested that the elevation of [O(3)] that has occurred since the industrial revolution is depressing A(sat) and g(s) by 11% (CI 9-13%) and 13% (CI 11-15%), respectively, where CI is the 95% confidence interval. In contrast to angiosperms, gymnosperms were not significantly affected. Both drought and elevated [CO(2)] significantly decreased the effect of ambient [O(3)]. Younger trees (<4 years) were affected less than older trees. Elevation of [O(3)] above current levels caused progressively larger losses of A(sat) and g(s), including gymnosperms. Results are consistent with the expectation that damage to photosynthesis depends on the cumulative uptake of ozone (O(3)) into the leaf. Thus, factors that lower g(s) lessen damage. Where both g(s) and [O(3)] were recorded, an overall decline in A(sat) of 0.21% per mmol m(-2) of estimated cumulative O(3) uptake was calculated. These findings suggest that rising [O(3)], an often overlooked aspect of global atmospheric change, is progressively depressing the ability of temperate and boreal forests to assimilate carbon and transfer water vapour to the atmosphere, with significant potential effects on terrestrial carbon sinks and regional hydrologies.     

Vertical and Horizontal Distributions of Zn,Cd, Pb,Cu, and Hg in Uncultivated Soil in the Vicinity of a Zinc Smelter at Odda,Norway

In the present work the extent and variation of Zn, Cd, Pb, Cu, and Hg loading in undisturbed surface soil (0–5 cm) and the vertical transport of the metals in soil profiles are studied in the vicinity of a zinc smelter in Norway. Three major controlling factors on the metal concentrations in soil have been assessed: 1) distance from the anthropogenic point source; 2) organic matter content (O.M.); and 3) the prevailing wind directions. Moreover metal distributions in proximal soil profiles in 1972 and 2003 are compared. Current concentrations of Zn, Cd, Pb, Cu, and Hg in surface soil reach 14000, 60, 980, 430, and 7.0 mg·kg ^{? 1} , respectively, near the smelter and decrease regularly with distance in the northerly direction according to the regression model (y = ax^{? b} ). The Zn concentrations are significantly different from the background range up to 30 km from the smelter, whereas the other metals approach background at only 10 km distance. Subsurface concentration peaks of Pb, Cu, and Hg are found at greater depth in soil profiles than peaks of Zn and Cd. Levels of Zn, Cd, and Pb in surface soil seem to have decreased from 1972 to 2003, whereas for Cu the levels appear not to be significantly different.