Plant Functional Types Differ in Their Long-term Nutrient Response to eCO2 in an Extensive Grassland

Increasing atmospheric CO2 enhances plant biomass production and may thereby change nutrient concentrations in plant tissues. The objective of this study was to identify the effect of elevated atmospheric CO2 concentrations on nutrient concentrations of grassland biomass that have been grown for 16 years (1998–2013). The grassland biomass grown at the extensively managed Giessen FACE experiment, fumigated with ambient and elevated CO2 (aCO2; eCO2; +20%) was harvested twice annually. Concentrations of C, N, P, K, Ca, Mg, Mn, Fe, Cu and Zn were determined separately for grasses, forbs and legumes. Under eCO2, the concentration of N was reduced in grasses, Ca was reduced in grasses and forbs, P was reduced in grasses but increased in legumes, Mg concentration was reduced in grasses, forbs and legumes and K was reduced in grasses but increased in forbs. The nutrient yield (in g nutrient yield of an element per m−2) of most elements indicated negative yield responses at a zero biomass response to eCO2 for grasses. K and Zn nutrient yields responded positively to eCO2 in forbs and Mn and Fe responded positively in forbs and legumes. The results suggest that under eCO2 the nutrient concentrations were not diluted by the CO2 fertilization effect. Rather, altered plant nutrient acquisitions via changed physiological mechanisms prevail for increased C assimilation under eCO2. Furthermore, other factors such as water or nutrient availability affected plant nutrient concentrations under eCO2.

Early Capture of Attention by Self-Face: Investigation Using a Temporal Order Judgment Task

Earlier work on self-face processing has reported a bias in the processing of self-face result in faster response to self-face in comparison to other familiar and unfamiliar faces (termed as self-face advantage or SFA). Even though most studies agree that the SFA occurs due to an attentional bias, there is little agreement regarding the stage at which it occurs. While a large number of studies show self-face influencing processing later at disengagement stage, early event-related potential components show differential activity for the self-face suggesting that SFA occurs early. We address this contradiction using a cueless temporal order judgment task that allows us to investigate early perceptual processing, while bias due to top-down expectation is controlled. A greater shift in point of subjective simultaneity for self-face would indicate a greater processing advantage at early perceptual stage. With help of two experiments, we show an early perceptual advantage for self-face, compared to both a friend’s face and an unfamiliar face (Experiment 1). This advantage is present even when the effect of criterion shift is minimized (Experiment 2). Interestingly, the magnitude of advantage is similar for self-friend and self-unfamiliar pair. The evidence from the two experiments suggests early capture of attention as a likely reason for the SFA, which is present for the self-face but not for other familiar faces.

The Effect of Face Masks on Forensic Face Matching: An Individual Differences Study

In the forensic face matching task, observers are presented with two unfamiliar faces and must determine whether they depict the same identity. Due to the Covid-19 pandemic, some governmental authorities require the use of face masks in public spaces. However, face masks impair face identification by disrupting holistic processing of faces. The present study explores the effect of face masks on forensic face matching. Compared to a full-view condition, performance decreased when a face mask was superimposed on one face (Experiment 1) and both faces (Experiment 2) of a pair. Although a positive correlation between the full-view and the mask conditions was found, high proficiency in the full-view condition did not always generalize to the mask condition. Additionally, the mask generally has a more negative impact in those participants with better performance in the full-view condition. The theoretical and practical implications of these findings are discussed.

Elevated Atmospheric CO2 Modifies Mostly the Metabolic Active Rhizosphere Soil Microbiome in the Giessen FACE Experiment

Elevated levels of atmospheric CO2 lead to the increase of plant photosynthetic rates, carbon inputs into soil and root exudation. In this work, the effects of rising atmospheric CO2 levels on the metabolic active soil microbiome have been investigated at the Giessen free-air CO2 enrichment (Gi-FACE) experiment on a permanent grassland site near Giessen, Germany. The aim was to assess the effects of increased C supply into the soil, due to elevated CO2, on the active soil microbiome composition. RNA extraction and 16S rRNA (cDNA) metabarcoding sequencing were performed from bulk and rhizosphere soils, and the obtained data were processed for a compositional data analysis calculating diversity indices and differential abundance analyses. The structure of the metabolic active microbiome in the rhizospheric soil showed a clear separation between elevated and ambient CO2 (p = 0.002); increased atmospheric CO2 concentration exerted a significant influence on the microbiomes differentiation (p = 0.01). In contrast, elevated CO2 had no major influence on the structure of the bulk soil microbiome (p = 0.097). Differential abundance results demonstrated that 42 bacterial genera were stimulated under elevated CO2. The RNA-based metabarcoding approach used in this research showed that the ongoing atmospheric CO2 increase of climate change will significantly shift the microbiome structure in the rhizosphere.

Estado da Questão sobre a Experimentação no Contexto Online: o que Dizem os Eventos da Área do Ensino de Física?

The research aimed to understand the State of the Question of experimentation in Physics in the online context through events organized by the Brazilian Physics Society and by the Brazilian Association for Distance Education. For this, we analyzed 40 articles through two categories: “Didactic tool: the potentials and limits that cross the use of the virtual and face-to-face experiment in the teaching of Physics” and “Online teaching spaces and strategies in the training of physics teachers”. We concluded that the integration between virtual and real resources is the realm of face-to-face, distance or hybrid modalities, constitutes as a way for the classes to become more interactive, leaving the teacher to use them in the creation of activities that expand collaborative actions in the classroom. Keywords: Experimentation. Online teaching. State of the question. Physics teaching. Resumo. A pesquisa buscou compreender o Estado da Questão sobre a experimentação em Física no contexto online através de eventos organizados pela Sociedade Brasileira de Física e Associação Brasileira de Educação a Distância. Para isso, analisamos 40 artigos por meio de duas categorias: “Ferramenta didática: as potencialidades e os limites que atravessam o uso do experimento virtual e presencial no ensino de Física” e “Espaços e estratégias didáticas online na formação de professores de Física”. Significamos que a integração entre recursos virtuais e reais no âmbito da modalidade presencial, a distância ou híbrida, constitui-se como um caminho para que as aulas se tornem mais interativas, cabendo ao professor utilizá-las na criação de atividades que ampliem as ações colaborativas em sala de aula. Palavras-chave: Experimentação. Ensino online. Estado da questão. Ensino de física.

Methane Stem Fluxes Under Elevated CO2

<p>Tree stems can exchange CH<sub>4</sub> with the atmosphere at rates that can strongly affect GHG budgets at regional scales. However, we do not know those fluxes’ sensitivity to different components of climate change, such as the increase in concentrations of atmospheric CO<sub>2</sub>. An increase in CO<sub>2</sub> concentrations might result in a change of water use efficiency, reducing transpiration fluxes, which may enhance soil methanogenesis due to an associated increase in soil water content. Additionally, an increase of CO<sub>2</sub> could also stimulate net primary production, increasing the supply of fresh carbohydrates to the rhizosphere, and thus stimulating CH<sub>4</sub> production in soil anaerobic microsites which may themselves become larger or more numerous due to the additional oxygen demand placed by the fresh carbohydrate on the soil atmosphere. Given the positive relation between soil and stem CH<sub>4</sub> exchange processes, any increase in soil CH<sub>4</sub> production may result in higher stem emissions. However, that effect of soil production on stem fluxes might decrease with stem height, with lower fluxes or even CH<sub>4</sub> uptake at higher stem heights. In this study, we present preliminary data on spatial and temporal variability of stem CH<sub>4</sub> fluxes measured in mature oak trees growing under both control and elevated CO<sub>2</sub> concentrations (~150 ppm above atmospheric concentrations) in a FACE experiment (free air CO<sub>2</sub> enrichment; BIFoR-FACE). These data may be crucial for informing processed based models on how forests GHG fluxes might behave under predicted future climate conditions.</p>