Single-celled eukaryotes (protists) are critical players in global biogeochemical cycling of nutrients and energy in the oceans. While their roles as primary producers and grazers are well ...appreciated, other aspects of their life histories remain obscure due to challenges in culturing and sequencing their natural diversity. Here, we exploit single-cell genomics and metagenomics data from the circumglobal Tara Oceans expedition to analyze the genome content and apparent oceanic distribution of seven prevalent lineages of uncultured heterotrophic stramenopiles. Based on the available data, each sequenced genome or genotype appears to have a specific oceanic distribution, principally correlated with water temperature and depth. The genome content provides hypotheses for specialization in terms of cell motility, food spectra, and trophic stages, including the potential impact on their lifestyles of horizontal gene transfer from prokaryotes. Our results support the idea that prominent heterotrophic marine protists perform diverse functions in ocean ecology.
•Adsorption desalination cycle using a metal organic framework was tested.•Effect of switching time on the amount of freshwater produced was studied.•Effect of two types of condenser on the amount of ...freshwater produced was assessed.•The cycle produced a freshwater of 9.5 m3/ton/day at an efficiency of 0.46.
The thermally driven adsorption desalination cycle has been considered a promising solution to mitigate the gap between freshwater needs and demands. Silica gel and zeolite are commonly used in the cycle however, they have low capacity. So, metal–organic framework adsorbents have been proposed as a replacement for silica gel and zeolite. Performance of the adsorption desalination cycle using metal–organic framework materials has been extensively investigated numerically with limited available experimental measurements in the open literature. In this work, a lab-scale adsorption desalination cycle using heat recovery was built using a metal organic framework (CPO-27(Ni)) as an adsorbent. Effect of the cycle time, switching time, condenser type, and cooling water temperature is assessed from the viewpoint of the cycle’s specific daily water production and gained output ratio. This investigation aims to specify the optimal cycle time and switching time. The experimental measurements identify that the optimal cycle time and switching time are 12 min and 30 s, respectively. At these conditions, the cycle produces a specific daily water production of 9.5 m3/ton/day at a gained output ratio value of 0.46. Using a coil condenser is found to be more efficient than using a finned-tube condenser. The specific daily water production decreases by 26% and the gained output ratio drops by about 22% when the cooling temperature increases from 15 to 35 °C. The present results indicate the importance of optimizing the operating conditions to achieve higher efficiency.
Uphill shifts of species' distributions in response to historical warming are well documented, which leads to widespread expectations of continued uphill shifts under future warming. Conversely, ...downhill shifts are often considered anomalous and unrelated to climate change. By comparing the altitudinal distributions of 64 plant species between the 1930s and the present day within California, we show that climate changes have resulted in a significant downward shift in species' optimum elevations. This downhill shift is counter to what would be expected given 20th-century warming but is readily explained by species' niche tracking of regional changes in climatic water balance rather than temperature. Similar downhill shifts can be expected to occur where future climate change scenarios project increases in water availability that outpace evaporative demand.
A novel boomerang-like alumina based antireflective coating with ultra-low reflectance has been produced for light incidence angles form 0 up to 45°. Boomerang-like alumina nanostructures have been ...fabricated on the BK7 glass substrates by dip-coating and surface modification via hot water treatment. To achieve the lowest residual reflectance, the effect of dip-coating rate and hot-water temperature in the treatment process has been investigated and optimized. To further investigate the boomerang-like alumina nanostructure and extract its graded refractive index profile by fitting the measured reflectance spectrum with the simulated one, a simulation based on the finite-difference time-domain (FDTD) method has been performed. The average reflectance measured at normal incidence for double-sided coated BK7 glass substrates is only 0.3% in the visible spectral region. Considering both sides, the average reflectance of the substrate decreased in the spectral range of 400-700 nm down to 0.4% at incidence angles of 45° by applying the boomerang-like alumina antireflection coatings. The optimized single layer boomerang-like alumina coating on the curved aspheric lens exhibited a low average reflectance of less than 0.14% and an average transmittance of above 99.3% at normal incidence. The presented process is a simple and cost-effective route towards broadband and omnidirectional antireflection coatings, which have promising potential to be applied on substrates having large scales with complex geometric shapes.
The construction of dams worldwide has substantially altered natural flow and thermal regimes, leading to profound influences on fish spawning. Environmental flow (EFlow) assessments provide ...information on the links between river flow and river health and are a useful technique for specifically restoring species' life-history requirements. A full understanding of the abiotic–biotic relationships coupled with information on hydrological events and ecological processes is a vital step for acquiring explicit water management options. However, the incorporation of concurrent and antecedent flow, thermal parameters, and other water quality information, particularly their complex interaction effects, into the prediction of the relationships between fish spawning and abiotic factors is poorly studied. The present study proposes a hierarchical modeling framework that accounts for the different concurrent and antecedent habitat factors and the interaction effects between factors to predict the spawning intensities of three important endemic fish species (which spawn drifting eggs) collected from the upper Yangtze River, China. Our results show that 1) the abiotic factors significantly affecting fish spawning vary with species, and these factors are intricately linked to species-specific ecology; 2) the water transparency during spawning and the accumulated temperature before spawning are important predictors of the spawning intensity of some fish species, while the effective duration of rising flow discharge before spawning plays a consistently important role in affecting the spawning intensity of all three fish species; and 3) there are explicit interaction effects, mainly between the hydrological and thermal variables, on fish spawning intensity. The present study suggests that investigation of the relationships between fish spawning and abiotic factors should not only analyze individual species but should also fully consider the accumulated temperature and effective duration of flow discharge rising before spawning, as well as the interaction effects between habitat factors.
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•A hierarchical model framework was developed for environmental flow management.•Interaction effects between the hydrological and thermal variables were evaluated.•Accumulated temperature before spawning affects fish spawning intensity.•Effective duration of flow rising before spawning affects fish spawning intensity.•Incorporating thermal variables into environmental flows assessments is necessary.
Several new discoveries suggest that the climate of the Cretaceous may have been more different from that of today than has been previously supposed. Detailed maps of climate-sensitive fossils and ...sediments compiled by Nicolai Chumakov and his colleagues in Russia indicate widespread aridity in the equatorial region during the Early Cretaceous. The very warm ocean temperatures postulated for the Mid-Cretaceous by some authors would likely have resulted in unacceptable heat stress for land plants at those latitudes, however, and may be flawed.
Seasonal reversals of the atmospheric pressure systems in the Polar Regions are an oversimplification. However, the seasonal pressure differences between 30° and 60° latitude became quite pronounced, being more than 25hPa in winter and less than 10hPa in summer. This resulted in inconstant winds, affecting the development of the gyre-limiting frontal systems that control modern ocean circulation. The idea of Hasegawa et al. (2012) who suggest a drastic reduction in the size of the Hadley cells during the warm Cretaceous greenhouse is supported by several numerical climate simulations. Rapid contraction of the Hadley cell such that its sinking dry air occurs at 15° N latitude rather than 30° N is proposed to occur at a threshold of 1000ppmv CO2 in the atmosphere. This change will probably be reached in the next century.
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•Anthropogenic impact has warming effect on the LSWT.•When human activities cause a 1℃ increase in LSWT, the overall average increase in LSWT is 0.24℃.•The impact of human social ...policies on the surface water temperature of lakes will continue.
In the past 40 years, the surface water temperature of lakes worldwide has generally shown an upward trend, with a significant spatial heterogeneity. Previous studies generally attributed the change in lake surface water temperature to direct impact of climate change. However, few studies have explored the potential impact of additional anthropogenic factors, resulting in an incomplete understanding of the anthropogenic influence on lake surface water temperatures. We thus propose a new method to quantify the anthropogenic impact on the surface water temperature of lakes. We selected 11 lakes characterized by significant variations in the intensity of watershed urbanization development on the Yunnan-Guizhou Plateau in China for an empirical study, and discussed the trend of LSWT (lake surface water temperature) changes under the anthropogenic impact, as well as the potential link between these changes and human social policies. The research results show that (1) The mean annual rate of change in LSWT due to anthropogenic impact fluctuates of 0.06℃ per year. (2) LSWT is sensitive to changes in anthropogenic activities; a 1℃ increase in LSWT due to anthropogenic factors typically results in a mean temperature variation of 0.24℃. (3) During the three years of the COVID-19 pandemic, LSWT on the Yunnan-Guizhou Plateau was significantly affected by anthropogenic activities.
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