Covariation in Plant Functional Traits and Soil Fertility within Two Species-Rich Forests

The distribution of plant species along environmental gradients is expected to be predictable based on organismal function. Plant functional trait research has shown that trait values generally vary predictably along broad-scale climatic and soil gradients. This work has also demonstrated that at any one point along these gradients there is a large amount of interspecific trait variation. The present research proposes that this variation may be explained by the local-scale sorting of traits along soil fertility and acidity axes. Specifically, we predicted that trait values associated with high resource acquisition and growth rates would be found on soils that are more fertile and less acidic. We tested the expected relationships at the species-level and quadrat-level (20×20 m) using two large forest plots in Panama and China that contain over 450 species combined. Predicted relationships between leaf area and wood density and soil fertility were supported in some instances, but the majority of the predicted relationships were rejected. Alternative resource axes, such as light gradients, therefore likely play a larger role in determining the interspecific variability in plant functional traits in the two forests studied

Report of the Topical Group on Top quark physics and heavy flavor production for Snowmass 2021

This report summarizes the work of the Energy Frontier Topical Group on EW Physics: Heavy flavor and top quark physics (EF03) of the 2021 Community Summer Study (Snowmass). It aims to highlight the physics potential of top-quark studies and heavy-flavor production processes (bottom and charm) at the HL-LHC and possible future hadron and lepton colliders and running scenarios

Report of the Topical Group on Electroweak Precision Physics and Constraining New Physics for Snowmass 2021

The precise measurement of physics observables and the test of their consistency within the standard model (SM) are an invaluable approach, complemented by direct searches for new particles, to determine the existence of physics beyond the standard model (BSM). Studies of massive electroweak gauge bosons (W and Z bosons) are a promising target for indirect BSM searches, since the interactions of photons and gluons are strongly constrained by the unbroken gauge symmetries. They can be divided into two categories: (a) Fermion scattering processes mediated by s- or t-channel W/Z bosons, also known as electroweak precision measurements; and (b) multi-boson processes, which include production of two or more vector bosons in fermion-antifermion annihilation, as well as vector boson scattering (VBS) processes. The latter categories can test modifications of gauge-boson self-interactions, and the sensitivity is typically improved with increased collision energy. This report evaluates the achievable precision of a range of future experiments, which depend on the statistics of the collected data sample, the experimental and theoretical systematic uncertainties, and their correlations. In addition it presents a combined interpretation of these results, together with similar studies in the Higgs and top sector, in the Standard Model effective field theory (SMEFT) framework. This framework provides a model-independent prescription to put generic constraints on new physics and to study and combine large sets of experimental observables, assuming that the new physics scales are significantly higher than the EW scale.Comment: 55 pages; Report of the EF04 topical group for Snowmass 202

Moderate chilling requirement controls budburst for subtropical species in China

It is well known that spring phenology has advanced in temperate regions over the last few decades in response to climate change. However, we understand much less about climate-driven changes in phenology within subtropical and tropical regions, where the timing of events is less predictable and has not been well-studied. It is not known whether subtropical plants have a similar winter chilling requirement to what has been well-documented in temperate species. To explore this possibility, we established a climate chamber experiment to test the effects of photoperiod and chilling on the timing of budburst within 37 subtropical woody species. We found that both moderate and strong chilling treatments advanced budburst and reduced forcing requirements, relative to plants subjected to a low chilling treatment. Longer photoperiod enhanced budburst rate for only two species, suggesting that chilling is more important for regulating budburst for most species. With respect to future climate change, the spring phenology of subtropical species is expected to be delayed further because species could lack the ability to meet their fundamental chilling requirement. These results have important implications for the conservation and management of tropical and subtropical plant populations under future climate change scenarios

Top of Atmosphere, Hyperspectral Synthetic Dataset for PACE (Phytoplankton, Aerosol, and ocean Ecosystem) Ocean Color Algorithm Development

This synthetic dataset was created to provide a measurement error-free hyperspectral (350-800 nm, 5 nm resolution) dataset as part of research performed by the first NASA PACE (Plankton, Aerosols, Cloud, and Ocean Ecosystem) Science Team (NNH13ZDA001N-PACEST). A synthetic dataset of sea surface and top of atmosphere (TOA) radiances were constructed by a Coupled Ocean Atmosphere Radiative Transfer (COART) model (Du and Lee, 2014) based on the SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer) code (Ricchiazzi et al. 1998), with ocean contribution simulated by Hydrolight (Mobley, 2008). Water-leaving radiance (Lw) was forward modelled with Hydrolight with a solar zenith angle of 30°, cloudless sky, a sea surface state corresponding to a wind speed of 5 m/s, and realistic concentrations of optically active water constituents. The Hydrolight component of the model was constrained using inherent optical properties (IOPs) whose dynamic ranges and spectral qualities were based on real, in situ data acquired from the NASA SeaBASS dataset (https://seabass.gsfc.nasa.gov/) and that represent realistic in situ conditions. Certain characteristics of the IOPs were semi-randomly modelled based on principles outlined in IOCCG Report No.5 (2006) and summarised in the accompanying pdf document provided along with this dataset. Atmospheric conditions were simulated by coupling the water-leaving radiances to an atmosphere with and without absorbing gases, and with an aerosol optical depth (AOD) that varied between 0.1-0.8

Diverging shifts in spring phenology in response to biodiversity loss in a subtropical forest

Questions Despite our increased understanding of how climate change influences plant phenology, it remains poorly understood whether diversity loss could alter phenology as well. Here we investigated the following: (a) do changes in plant diversity affect leaf-out and flowering dates for woody species; (b) which group of variables are more important in influencing leaf-out and flowering dates, abiotic variables (soil variables) or biotic variables (plant diversity)? Study site A subtropical forest in the Biodiversity-Ecosystem Functioning Experiment of China, located in Jiangxi Province, China. Methods Species were planted in various combinations to create plots with varying tree richness: 1, 2, 4, 8, 16 or 24 species. We monitored leaf-out and flowering dates of eight randomly selected species in 17 plots in 2018. A linear model was used to test whether species diversity was a predictor of leaf-out/flowering times for each species. We then fit linear mixed-effects models to assess the combined influence of species diversity, soil Total Carbon and Total Nitrogen on the overall community. Results In the low-diversity plots, we found two species leafing out earlier, one leafing out later and four showing no significant difference. Leaf-out date advanced an average of 0.3 days per species lost. Of all the biotic and abiotic predictor variables, Total Nitrogen was the only one significantly correlated with leaf-out date. No significant correlation was found between species diversity and flowering date for any of the species. Conclusions Our study provides the first empirical evidence concerning the effects of biodiversity loss on plant spring phenology for woody species. Our findings illustrate that fluctuation in plant diversity could alter the timing of leaf-out and that abiotic variables may be more important than biotic variables in determining leaf-out dates in subtropical forest. Overall, declining diversity may exacerbate the phenological changes attributed to rising global temperatures