Multi-wavelength study of the turbulent central engine of the low-mass agn hosted by Ngc404

The nearby dwarf galaxy NGC 404 harbors a low-luminosity active galactic nucleus powered by the lowest-mass (<150,000 M ⊙) central massive black hole (MBH), with a dynamical mass constraint, currently known, thus providing a rare low-redshift analog to the MBH "seeds" that formed in the early universe. Here, we present new imaging of the nucleus of NGC 404 at 12–18 GHz with the Karl G. Jansky Very Large Array (VLA) and observations of the CO(2–1) line with the Atacama Large Millimeter/Submillimeter Array (ALMA). For the first time, we have successfully resolved the nuclear radio emission, revealing a centrally peaked, extended source spanning 17 pc. Combined with previous VLA observations, our new data place a tight constraint on the radio spectral index and indicate an optically thin synchrotron origin for the emission. The peak of the resolved radio source coincides with the dynamical center of NGC 404, the center of a rotating disk of molecular gas, and the position of a compact, hard X-ray source. We also present evidence for shocks in the NGC 404 nucleus from archival narrowband HST imaging, Chandra X-ray data, and Spitzer mid-infrared spectroscopy, and discuss possible origins for the shock excitation. Given the morphology, location, and steep spectral index of the resolved radio source, as well as constraints on nuclear star formation from the ALMA CO(2–1) data, we find the most likely scenario for the origin of the radio source in the center of NGC 404 to be a radio outflow associated with a confined jet driven by the active nucleus

Global maps of soil temperature.

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km &lt;sup&gt;2&lt;/sup&gt; resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km &lt;sup&gt;2&lt;/sup&gt; pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Interactive effects of temperature and habitat complexity on freshwater communities

Warming can lead to increased growth of plants or algae at the base of the food web, which may increase the overall complexity of habitat available for other organisms. Temperature and habitat complexity have both been shown to alter the structure and functioning of communities, but they may also have interactive effects, for example, if the shade provided by additional habitat negates the positive effect of temperature on understory plant or algal growth. This study explored the interactive effects of these two major environmental factors in a manipulative field experiment, by assessing changes in ecosystem functioning (primary production and decomposition) and community structure in the presence and absence of artificial plants along a natural stream temperature gradient of 5–18°C. There was no effect of temperature or habitat complexity on benthic primary production, but epiphytic production increased with temperature in the more complex habitat. Cellulose decomposition rate increased with temperature, but was unaffected by habitat complexity. Macroinvertebrate communities were less similar to each other as temperature increased, while habitat complexity only altered community composition in the coldest streams. There was also an overall increase in macroinvertebrate abundance, body mass, and biomass in the warmest streams, driven by increasing dominance of snails and blackfly larvae. Presence of habitat complexity, however, dampened the strength of this temperature effect on the abundance of macroinvertebrates in the benthos. The interactive effects that were observed suggest that habitat complexity can modify the effects of temperature on important ecosystem functions and community structure, which may alter energy flow through the food web. Given that warming is likely to increase habitat complexity, particularly at higher latitudes, more studies should investigate these two major environmental factors in combination to improve our ability to predict the impacts of future global change

Variation in Plant Litter Decomposition Rates across Extreme Dry Environments in Qatar

Decomposition of plant litter is a key process for transfer of carbon and nutrients in ecosystems. Carbon contained in decaying biomass is released to the atmosphere as respired CO2, a greenhouse gas that contributes to global warming. To our knowledge, there have been no studies on litter decomposition in terrestrial ecosystems in the Arabian peninsula. Here we used commercial teabags (green tea, rooibos tea) as standard substrates to study decomposition rates across contrasting ecosystems in Qatar. Teabags were buried under and beside Acacia tortilis trees, in depressions with abundant grass vegetation, in saltmarsh without and with vegetation, under Zygophyllum qatarense in drylands, in natural mangrove and in planted mangrove. There were signifcant site effects across ecosystems on decomposition rate (k), litter stabilisation factor (S), fnal weight of green tea and fnal weight of rooibos tea. Mangrove and depressions with grassland had the smallest amounts of remaining green and rooibos tea after the incubation period (69-82 days), while teabags buried under A. tortilis and in saltmarsh without vegetation had the largest amounts. Thus decomposition rates differ among ecosystems in the desert environment. Further multi-year and site studies are needed to identify factorsthatinfuence decomposition rates across sites in extreme environments

Variation in Plant Litter Decomposition Rates across Extreme Dry Environments in Qatar

Decomposition of plant litter is a key process for transfer of carbon and nutrients in ecosystems. Carbon contained in decaying biomass is released to the atmosphere as respired CO2, a greenhouse gas that contributes to global warming. To our knowledge, there have been no studies on litter decomposition in terrestrial ecosystems in the Arabian peninsula. Here we used commercial teabags (green tea, rooibos tea) as standard substrates to study decomposition rates across contrasting ecosystems in Qatar. Teabags were buried under and beside Acacia tortilis trees, in depressions with abundant grass vegetation, in saltmarsh without and with vegetation, under Zygophyllum qatarense in drylands, in natural mangrove and in planted mangrove. There were signifcant site effects across ecosystems on decomposition rate (k), litter stabilisation factor (S), fnal weight of green tea and fnal weight of rooibos tea. Mangrove and depressions with grassland had the smallest amounts of remaining green and rooibos tea after the incubation period (69-82 days), while teabags buried under A. tortilis and in saltmarsh without vegetation had the largest amounts. Thus decomposition rates differ among ecosystems in the desert environment. Further multi-year and site studies are needed to identify factorsthatinfuence decomposition rates across sites in extreme environments

Improving niche projections of plant species under climate change: Silene acaulis on the British Isles as a case study

Empirical works to assist in choosing climatically relevant variables in the attempt to predict climate change impacts on plant species are limited. Further uncertainties arise in choice of an appropriate niche model. In this study we devised and tested a sharp methodological framework, based on stringent variable ranking and filtering and flexible model selection, to minimize uncertainty in both niche modelling and successive projection of plant species distributions. We used our approach to develop an accurate, parsimonious model of Silene acaulis (L.) presence/absence on the British Isles and to project its presence/absence under climate change. The approach suggests the importance of (a) defining a reduced set of climate variables, actually relevant to species presence/absence, from an extensive list of climate predictors, and (b) considering climate extremes instead of, or together with, climate averages in projections of plant species presence/absence under future climate scenarios. Our methodological approach reduced the number of relevant climate predictors by 95.23% (from 84 to only 4), while simultaneously achieving high cross-validated accuracy (97.84%) confirming enhanced model performance. Projections produced under different climate scenarios suggest that S. acaulis will likely face climate-driven fast decline in suitable areas on the British Isles, and that upward and northward shifts to occupy new climatically suitable areas are improbable in the future. Our results also imply that conservation measures for S. acaulis based upon assisted colonization are unlikely to succeed on the British Isles due to the absence of climatically suitable habitat, so different conservation actions (seed banks and/or botanical gardens) are needed.Scopu

Closing a gap - First records of bryophytes from the Qatar Peninsula

The ephemeral or annual mosses Entosthodon fascicularis (Funariaceae), Microbryum starckeanum (Pottiaceae) and Pohlia melanodon (Mniaceae) were found in the understorey of natural Ziziphus nummularia shrubland in Qatar. These are the first records of bryophytes from the Qatar Peninsula, hence bridging the distribution gap on the Arabian Peninsula. Their site ecology, establishment and habitat maintenance conditions in the desert landscape of Umm Al Shukhoot are discussed.Scopu

Quantifying ecosystem services supply and demand shortfalls and mismatches for management optimisation

Research on ecosystem services (ESs) has increased substantially in recent decades, but the findings have been slow to affect actual management, perhaps because most studies to date have neglected ESs supply and demand coupling mechanisms. Human reliance on ESs is due to the capacity of the landscape to supply services, but also to a societal need for these services. Sustainable land management requires supply and demand mismatches to be reconciled and the needs of different stakeholders to be balanced. Explicit spatial mapping of ESs supply and demand associated with land use changes can provide relevant insights for enhancing land management in urban areas. The emphasis is now shifting to enhancing sustainable land use, to ensure that supply meets or exceeds demand. In this study, a comprehensive framework comprising four core steps for quantifying ESs supply and demand changes associated with land use changes was developed and applied in a case study on Shanghai municipality, on the basis of environmental quality standards and policy goals. The balance thresholds of ESs supply and demand were derived by regression analysis between ESs and land use/land cover types. The results revealed large spatial heterogeneity in supply and demand for four key ESs tested: carbon sequestration, water retention, particulate (PM10) removal and recreation. Carbon sequestration, water retention and recreation services all showed major shortfalls in supply that changed dramatically with urban land use change. This is valuable empirical evidence and has timely policy implications for management in a rapid urbanising world.This study was supported by the Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences ( WSGS2017008 ), the National Natural Science Foundation of China ( 41771571 ), the National Key Research and Development Program of China ( 2017YFC0404600 ).Scopu