Reconstructing the anatomy of the 42-million-year-old fossil †Mengea tertiaria (Insecta, Strepsiptera)

Fossilization in amber is unique in preserving specimens with microscopic fidelity; however, arthropod inclusions are rarely examined beyond the exoskeleton as this requires destructive sampling when traditional techniques are used. We report the first complete, digital 3D, non-destructive reconstruction of the anatomy of an insect fossil, a specimen of †Mengea tertiaria embedded in a 42-Ma Baltic amber. This was made possible using Synchrotron μ-CT. The species belongs to the stem group of the phylogenetically enigmatic and extremely specialized Strepsiptera. Most internal structures of the fossil are preserved, but small parts of the lumen had decayed due to incomplete infiltration of the resin. Data on internal organs provided additional information for resolving phylogenetic relationships. A sister group relationship between †Mengea and all extant lineages of the group was confirmed with characters previously not accessible. The newly gained information also yielded some insights in the biology of †Mengea and the early evolutionary history of Strepsiptera. The technique has a tremendous potential for a more accurate interpretation of diverse fossil arthropods preserved in ambers from 130 Ma to the present.     

An expanded conceptual framework for solution-focused management of chemical pollution in European waters

Background

This paper describes a conceptual framework for solutions-focused management of chemical contaminants built on novel and systematic approaches for identifying, quantifying and reducing risks of these substances.

Methods

The conceptual framework was developed in interaction with stakeholders representing relevant authorities and organisations responsible for managing environmental quality of water bodies. Stakeholder needs were compiled via a survey and dialogue. The content of the conceptual framework was thereafter developed with inputs from relevant scientific disciplines.

Results

The conceptual framework consists of four access points: Chemicals, Environment, Abatement and Society, representing different aspects and approaches to engaging in the issue of chemical contamination of surface waters. It widens the scope for assessment and management of chemicals in comparison to a traditional (mostly) perchemical risk assessment approaches by including abatement- and societal approaches as optional solutions. The solution-focused approach implies an identification of abatement- and policy options upfront in the risk assessment process. The conceptual framework was designed for use in current and future chemical pollution assessments for the aquatic environment, including the specific challenges encountered in prioritising individual chemicals and mixtures, and is applicable for the development of approaches for safe chemical management in a broader sense. The four access points of the conceptual framework are interlinked by four key topics representing the main scientific challenges that need to be addressed, i.e.: identifying and prioritising hazardous chemicals at different scales; selecting relevant and efficient abatement options; providing regulatory support for chemicals management; predicting and prioritising future chemical risks. The conceptual framework aligns current challenges in the safe production and use of chemicals. The current state of knowledge and implementation of these challenges is described.

Conclusions

The use of the conceptual framework, and addressing the challenges, is intended to support: (1) forwarding sustainable use of chemicals, (2) identification of pollutants of priority concern for cost-effective management, (3) the selection of optimal abatement options and (4) the development and use of optimised legal and policy instruments.

     

Can current management maintain forest landscape multifunctionality in the Eastern Alps in Austria under climate change?

In Central Europe, management of forests for multiple ecosystem services (ES) has a long tradition and is currently drawing much attention due to increasing interest in non-timber services. In face of a changing climate and diverse ES portfolios, a key issue for forest managers is to assess vulnerability of ES provisioning. In a case study catchment of 250 ha in the Eastern Alps, the currently practiced uneven-aged management regime (BAU; business as usual) which is based on irregularly shaped patch cuts along skyline corridors was analysed under historic climate (represented by the period 1961–1990) and five transient climate change scenarios (period 2010–2110) and compared to an unmanaged scenario (NOM). The study addressed (1) the future provisioning of timber, carbon sequestration, protection against gravitational hazards, and nature conservation values under BAU management, (2) the effect of spatial scale (1, 5, 10 ha grain size) in mapping ES indicators and (3) how the spatial scale of ES assessment affects the simultaneous provision of several ES (i.e. multifunctionality). The analysis employed the PICUS forest simulation model in combination with novel landscape assessment tools. In BAU management, timber harvests were smaller than periodic increments. The resulting increase in standing stock benefitted carbon sequestration. In four out of five climate change scenarios, volume increment was increasing. With the exception of the mildest climate change scenario (+2.6 °C, no change in precipitation), all other analysed climate change scenarios reduced standing tree volume, carbon pools and number of large old trees, and increased standing deadwood volume due to an intensifying bark beetle disturbance regime. However, increases in deadwood and patchy canopy openings benefitted bird habitat quality. Under historic climate, the NOM regime showed better performance in all non-timber ES. Under climate change conditions, the damages from bark beetle disturbances increased more in NOM compared with BAU. Despite favourable temperature conditions in climate change scenarios, the share of admixed broadleaved species was not increasing in BAU management, mainly due to the heavy browsing pressure by ungulates. In NOM, it even decreased and mean tree age increased. Thus, in the long run NOM may enter a phase of lower resilience compared with BAU. Most ES indicators were fairly insensitive to the spatial scale of indicator mapping. ES indicators that were based on sparse tree and stand attributes such as rare admixed tree species, large snags and live trees achieved better results when mapped at larger scales. The share of landscape area with simultaneous provisioning of ES at reasonable performance levels (i.e. multifunctionality) decreased with increasing number of considered ES, while it increased with increasing spatial scale of the assessment. In the case study, landscape between 53 and 100 % was classified as multifunctional, depending on number and combinations of ES.     

Arsenite toxicity and uptake rate of rice (Oryza sativa L.) in vivo

Toxicity threshold of arsenite on intact rice seedlings was determined and arsenite uptake characteristics were investigated using non-toxic concentrations of arsenite.The arsenite toxicity threshold was 2.4 μM arsenite which reduced growth by 10% (EC₁₀). The two highest arsenite levels induced wilting of seedlings and reduced both, transpiration rate and net photosynthetic rate. Arsenic content in plant tissue increased up to 10.7 μM arsenite and then declined with increasing arsenite concentration in the treatment solution. The contents of Si, P, K, and of micronutrients Cu, Fe, Mn and Zn in shoot d.m. were reduced by arsenite levels ≥ 5.3 μM. In the non-toxic range, arsenite uptake rate was linearly related to arsenite concentration.High arsenite levels reduced growth without being taken up which might be due to increasing binding of arsenite to proteins at the outer side of the plasmalemma.     

Modelling bark beetle disturbances in a large scale forest scenario model to assess climate change impacts and evaluate adaptive management strategies

To study potential consequences of climate-induced changes in the biotic disturbance regime at regional to national scale we integrated a model of Ips typographus (L. Scol. Col.) damages into the large-scale forest scenario model EFISCEN. A two-stage multivariate statistical meta-model was used to upscale stand level damages by bark beetles as simulated in the hybrid forest patch model PICUS v1.41. Comparing EFISCEN simulations including the new bark beetle disturbance module against a 15-year damage time series for Austria showed good agreement at province level (R2 between 0.496 and 0.802). A scenario analysis of climate change impacts on bark beetle-induced damages in Austria’s Norway spruce [Picea abies (L.) Karst.] forests resulted in a strong increase in damages (from 1.33 Mm3 a⁻¹, period 1990–2004, to 4.46 Mm3 a⁻¹, period 2095–2099). Studying two adaptive management strategies (species change) revealed a considerable time-lag between the start of adaptation measures and a decrease in simulated damages by bark beetles.     

Climate change adaptation and sustainable regional development: a case study for the Federal State of Brandenburg, Germany

Located in a relatively dry region and characterized by mainly sandy soils, the German Federal State of Brandenburg (surrounding the capital city of Berlin) is especially vulnerable to climate change impacts (e.g., summer droughts) and cascading effects on ecological systems (e.g., decreasing ground water tables, water stress, fire risk, productivity losses) with socioeconomic implications. Furthermore, a complex interplay of unemployment, rural exodus, and an aging population challenges this structurally weak region. We discuss adaptation measures that are either implemented or planned, as well as research into adaptation strategies to climate change for the sectors forestry, agriculture, and water management as well as in nature conservation in light of socioeconomic and ecological challenges and benefits. In doing so, we adopt a systemic view of Brandenburg where the sectors discussed are seen as subsystems embedded in a larger regional system. This at least partially holarchical approach enables the identification of conflicts between adaptation measures, but also of synergies among the sectors that pertain to successful adaptation to climate change. The insights gained ultimately highlight the need for cross-sectoral, adaptive management practices that jointly target a sustainable regional development.     

Characterization of slow pyrolysis biochars: effects of feedstocks and pyrolysis temperature on biochar properties

Biochars are increasingly used as soil amendment and for C sequestration in soils. The influence of feedstock differences and pyrolysis temperature on biochar characteristics has been widely studied. However, there is a lack of knowledge about the formation of potentially toxic compounds that remain in the biochars after pyrolysis. We investigated biochars from three feedstocks (wheat straw, poplar wood, and spruce wood) that were slowly pyrolyzed at 400, 460, and 525°C for 5 h (straw) and 10 h (woodchips), respectively. We characterized the biochars' pH, electrical conductivity, elemental composition (by dry combustion and X-ray fluorescence), surface area (by N adsorption), water-extractable major elements, and cation exchange capacity (CEC). We further conducted differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffractometry to obtain information on the biochars' molecular characteristics and mineralogical composition. We investigated trace metal content, total polycyclic aromatic hydrocarbon (PAH) content, and PAH composition in the biochars. The highest salt (4.92 mS cm) and ash (12.7%) contents were found in straw-derived biochars. The H/C ratios of biochars with highest treatment temperature (HTT) 525°C were 0.46 to 0.40. Surface areas were low but increased (1.8-56 m g) with increasing HTT, whereas CEC decreased (162-52 mmol kg) with increasing HTT. The results of DSC and FTIR suggested a loss of labile, aliphatic compounds during pyrolysis and the formation of more recalcitrant, aromatic constituents. X-ray diffractometry patterns indicated a mineralogical restructuring of biochars with increasing HTT. Water-extractable major and trace elements varied considerably with feedstock composition, with trace elements also affected by HTT. Total PAH contents (sum of EPA 16 PAHs) were highly variable with values up to 33.7 mg kg; irrespective of feedstock type, the composition of PAHs showed increasing dominance of naphthalene with increasing HTT. The results demonstrate that biochars are highly heterogeneous materials that, depending on feedstock and HTT, may be suitable for soil application by contributing to the nutrient status and adding recalcitrant C to the soil but also potentially pose ecotoxicological challenges.     

Metabolism of gamma‐hexachlorocyclohexah (HCH) in vivo. Metabolism of orally administered gamma‐2,3,4,5,6‐pentachlorocyclohexen (PCCH)

Abstract

Mexacarbate (4‐dimethylamino‐3,5‐xylyl N‐methylcarbamate) insecticide has potential for use in spruce budworm (Choristoneura fumiferana Clem.) control operations in Canada. Its persistence and fate in balsam fir (Abies balsamea (L.) Mill.), litter and soil samples were studied by spraying aerially oil‐based and water‐based formulations, each at 70 g A.I./ha over a coniferous forest near Bathurst, New Brunswick. The oil‐based formulation gave the maximum concentration of the chemical in the substrates studied. In fir needles, the highest concentrations observed were 0.51 ppm and 0.19 ppm (fresh weight) for the oil‐based and emulsion formulations respectively, 1 h after application. The residue levels decreased very rapidly with a half‐life of approximately 5 h. Three and eight days after the spray application of the emulsion and oil formulations respectively, the concentrations of mexacarbate in foliage decreased to trace levels ( 0.008 ppm). Only very low levels of residue were detected in litter and soil. The peak concentrations for the two formulations ranged from 0.02 to 0.11 ppm (fresh weight) in litter and from 0.01 to 0.06 ppm (fresh weight) in soil. The residue levels in both litter and soil decreased to below the detection limit (0.005 ppm) within 1 d. The ground deposit levels found on glass plates and the droplet density and size spectra measured on Kromekote® cards reflected the variations in concentrations found in fir needles, litter and soil samples and correlated with the observed maximum concentrations in them. Under the stipulated use pattern, mexacarbate concentrations found in the terrestrial components studied were low and are not likely to have any undue adverse effects on non‐target species.     

Post-mating odor in females of the solitary bee, Andrena nigroaenea (Apoidea, Andrenidae), inhibits male mating behavior

We investigated odor changes and their behavioral significance in the solitary, ground-nesting bee Andrena nigroaenea. We used gas chromatography with electroantennographic detection and performed behavioral tests with males in the field using natural odor samples and synthetic compounds. We found that only cuticle extracts of young females elicited copulation attempts in the males. We demonstrated that among the 17 compounds which triggered electroantennographic responses, all-trans-farnesyl hexanoate and all-trans-farnesol were significantly more abundant in unattractive cuticle extracts of A. nigroaenea females. Dufour’s gland extracts of these females also contained greater amounts of both compounds. In bioassays using synthetic farnesyl hexanoate and farnesol we found that these compounds inhibit copulation behavior in the males. Farnesyl hexanoate is probably synthesized in Dufour’s gland and used by females for lining brood cells. We interpret the semiochemical function of farnesyl hexanoate and its precursor farnesol to have evolved secondarily. As an outcome of sexual selection, it facilitates the discrimination by males of receptive females from nesting and thus already mated individuals. The dual function of these compounds represents an elegant parsimony in the chemical communication system of this insect. Received: 19 January 2000 / Revised: 29 May 2000 / Accepted: 24 June 2000     

Detection of methylquinoline transformation products in microcosm experiments and in tar oil contaminated groundwater using LC-NMR

N-heterocyclic compounds are known pollutants at tar oil contaminated sites. Here we report the degradation of methyl-, and hydroxy-methyl-substituted quinolines under nitrate-, sulfate- and iron-reducing conditions in microcosms with aquifer material of a former coke manufacturing site. Comparison of degradation potential and rate under different redox conditions revealed highest degradation activities under sulfate-reducing conditions, the prevailing conditions in the field. Metabolites of methylquinolines, with the exception of 2-methylquinolines, were formed in high amounts in the microcosms and could be identified by ¹H NMR spectroscopy as 2(1H)-quinolinone analogues. 4-Methyl-, 6-methyl-, and 7-methyl-3,4-dihydro-2(1H)-quinolinone, the hydrogenated metabolites in the degradation of quinoline compounds, were identified by high resolution LC-MS. Metabolites of methylquinolines showed persistence, although for the first time a transformation of 4-methylquinoline and its metabolite 4-methyl-2(1H)-quinolinone is described. The relevance of the identified metabolites is supported by the detection of a broad spectrum of them in groundwater of the field site using LC-NMR technique. LC-NMR allowed the differentiation of isomers and identification without reference compounds. A variety of methylated 2(1H)-quinolinones, as well as methyl-3,4-dihydro-2(1H)-quinolinone isomers were not identified before in groundwater.