Towards a coupled paradigm of NH3‐CO2 biosphere–atmosphere exchange modelling

Stomatal conductance, one of the major plant physiological controls within NH₃ biosphere–atmosphere exchange models, is commonly estimated from semi‐empirical multiplicative schemes or simple light‐ and temperature‐response functions. However, due to their inherent parameterization on meteorological proxy variables, instead of a direct measure of stomatal opening, they are unfit for the use in climate change scenarios and of limited value for interpreting field‐scale measurements. Alternatives based on H₂O flux measurements suffer from uncertainties in the partitioning of evapotranspiration at humid sites, as well as a potential decoupling of transpiration from stomatal opening in the presence of hygroscopic particles on leaf surfaces. We argue that these problems may be avoided by directly deriving stomatal conductance from CO₂ fluxes instead. We reanalysed a data set of NH₃ flux measurements based on CO₂‐derived stomatal conductance, confirming the hypothesis that the increasing relevance of stomatal exchange with the onset of vegetation activity caused a rapid decrease of observed NH₃ deposition velocities. Finally, we argue that developing more mechanistic representations of NH₃ biosphere–atmosphere exchange can be of great benefit in many applications. These range from model‐based flux partitioning, over deposition monitoring using low‐cost samplers and inferential modelling, to a direct response of NH₃ exchange to climate change.     

Is there really no place like home? Movement, site fidelity, and survival probability of translocated and resident turtles

Wildlife translocations, the deliberate movement of wild individuals from one part of their distribution to another, are increasingly being used as a conservation tool. Despite the popularity of translocations as a conservation technique, translocations are often not successful as a result of excessive movement, poor release site fidelity, and low survival. This study compares the movement patterns, site fidelity, and survival probability of resident and hard-released musk turtles (Sternotherus odoratus) in a complex of patchy distributed wetlands. Our results are different from most translocation studies as the majority of translocated turtles had movement (minimum convex polygon area, total distance moved, number of wetlands used, and the number of movement shifts between wetlands), release site fidelity, and wetland fidelity patterns that were similar to resident turtles. In addition, the survival probabilities of resident and translocated turtles were both high. We believe the combination of poor overland movement capabilities and the patchy distribution of wetlands surrounded by a strong boundary matrix of terrestrial habitat, potentially increased the costs of leaving the wetland. The high costs of travelling overland to more distant wetlands may have constrained the translocated turtles dispersal from the release site and increased release site fidelity. Our study suggests that hard-release translocations may be an effective conservation method for highly aquatic species unlikely to leave the wetland and travel long overland distances.     

Experimente mit Gummibärchen

Experiments with gummy bears With gelatin in the form of gummy bears, the differences to vegetable gelling agents can be easily demonstrated by simple experiments. How these gummy bears can also be used to produce sustainable labels is shown in this article. The presented experiments and instructions are part of a experiment kit with teaching materials for the implementation of a project week in schools with the topic “sustainability”.     

Metabolite profiling and quantitative genetics of natural variation for flavonoids in Arabidopsis

Little is known about the range and the genetic bases of naturally occurring variation for flavonoids. Using Arabidopsis thaliana seed as a model, the flavonoid content of 41 accessions and two recombinant inbred line (RIL) sets derived from divergent accessions (Cvi-0×Col-0 and Bay-0×Shahdara) were analysed. These accessions and RILs showed mainly quantitative rather than qualitative changes. To dissect the genetic architecture underlying these differences, a quantitative trait locus (QTL) analysis was performed on the two segregating populations. Twenty-two flavonoid QTLs were detected that accounted for 11-64% of the observed trait variations, only one QTL being common to both RIL sets. Sixteen of these QTLs were confirmed and coarsely mapped using heterogeneous inbred families (HIFs). Three genes, namely TRANSPARENT TESTA (TT)7, TT15, and MYB12, were proposed to underlie their variations since the corresponding mutants and QTLs displayed similar specific flavonoid changes. Interestingly, most loci did not co-localize with any gene known to be involved in flavonoid metabolism. This latter result shows that novel functions have yet to be characterized and paves the way for their isolation.     

Adapting test timing to the sleep-wake schedule: effects on diurnal neurobehavioral performance changes in young evening and older morning chronotypes

The synchrony effect refers to the beneficial impact of temporal matching between the timing of cognitive task administration and preferred time-of-day for diurnal activity. Aging is often associated with an advance in sleep-wake timing and concomitant optimal performance levels in the morning. In contrast, young adults often perform better in the evening hours. So far, the synchrony effect has been tested at fixed clock times, neglecting the individual's sleep-wake schedule and thus introducing confounds, such as differences in accumulated sleep pressure or circadian phase, which may exacerbate synchrony effects. To probe this hypothesis, the authors tested older morning and young evening chronotypes with a psychomotor vigilance and a Stroop paradigm once at fixed morning and evening hours and once adapting testing time to their preferred sleep-wake schedule in a within-subject design. The authors observe a persistence of synchrony effects for overall median reaction times during a psychomotor vigilance task, even when testing time is adapted to the specific individual's sleep-wake schedule. However, data analysis also indicates that time-of-day modulations are weakened under those conditions for incongruent trials on Stroop performance and the slowest reaction times on the psychomotor vigilance task. The latter result suggests that the classically observed synchrony effect may be partially mediated by a series of parameters, such as differences in socio-professional timing constraints, the amount of accumulated sleep need, or circadian phase, all leading to differential arousal levels at testing.     

Jelly-falls historic and recent observations: a review to drive future research directions

The biological pump describes the transport of particulate matter from the sea surface to the ocean’s interior including the seabed. The contribution by gelatinous zooplankton bodies as particulate organic matter (POM) vectors (“jelly-falls”) has been neglected owing to technical and spatiotemporal sampling limitations. Here, we assess the existing evidence on jelly-falls from early ocean observations to present times. The seasonality of jelly-falls indicates that they mostly occur after periods of strong upwelling and/or spring blooms in temperate/subpolar zones and during late spring/early summer. A conceptual model helps to define a jelly-fall based on empirical and field observations of biogeochemical and ecological processes. We then compile and discuss existing strategic and observational oceanographic techniques that could be implemented to further jelly-falls research. Seabed video- and photography-based studies deliver the best results, and the correct use of fishing techniques, such as trawling, could provide comprehensive regional datasets. We conclude by considering the possibility of increased gelatinous biomasses in the future ocean induced by upper ocean processes favouring their populations, thus increasing jelly-POM downward transport. We suggest that this could provide a “natural compensation” for predicted losses in pelagic POM with respect to fuelling benthic ecosystems.     

Management,winter climate and plant–soil feedbacks on ski slopes: a synthesis

Owing to the increasing popularity of skiing and the upslope movement of the snow reliability line in mountain regions, more and more alpine environments are being turned into skiing areas, with strong impacts on ecosystem functions and biodiversity. Creation and management of ski slopes cause physical disturbance to soil and vegetation, while (artificial) snow supplements affect soil structure, chemistry, moisture and temperature regimes as well as shifts in snow season and growing season length. Vegetation–soil feedbacks may influence the outcome of these interactive effects on soil and vegetation, with possible consequences for soil erosion. Moreover, climate warming will lead to changing snow cover and duration, which will interact with ski slope management effects on soil and vegetation and its feedbacks. Based on a conceptual framework we review the main elements of these interactive effects on soil and vegetation on new and established ski slopes. We also set a research agenda with specific studies that could further advance our understanding of interacting ski slope management, winter climate, vegetation–soil feedbacks and ecosystem functioning. In such new investigations, alpine climate change ecology can probably learn much from the “experimental” disturbance and snow manipulations on ski slopes and vice versa.     

Solution structure of the strawberry allergen Fra a 1

The PR10 family protein Fra a 1E from strawberry (Fragaria x ananassa) is down-regulated in white strawberry mutants, and transient RNAi (RNA interference)-mediated silencing experiments confirmed that Fra a 1 is involved in fruit pigment synthesis. In the present study, we determined the solution structure of Fra a 1E. The protein fold is identical with that of other members of the PR10 protein family and consists of a seven-stranded antiparallel β-sheet, two short V-shaped α-helices and a long C-terminal α-helix that encompass a hydrophobic pocket. Whereas Fra a 1E contains the glycine-rich loop that is highly conserved throughout the protein family, the volume of the hydrophobic pocket and the size of its entrance are much larger than expected. The three-dimensional structure may shed some light on its physiological function and may help to further understand the role of PR10 proteins in plants.