An official website of the United States government
Abstract Climate and land management affect nutrient cycling in grassland ecosystems. We aimed to understand whether temperate and tropical grasslands differ in terms of soil organic carbon (SOC), nitrogen (N), and phosphorus (P) concentrations, and their C:N:P stoichiometric ratios in grazed and ungrazed natural grasslands and pastures. For this, we used a meta-analysis approach (1296 records, 241 papers), and regression models to explain the observed patterns in terms of mean annual precipitation (MAP), mean annual temperature (MAT), altitude, and latitude. SOC, N, and P concentrations were higher in temperate regions than in tropical ones, and they negatively correlated with MAT and MAP. The grassland type effect was more significant for tropical regions. In tropical regions, soil C:N ratios were higher in ungrazed than in grazed pastures, and soil N:P ratios in ungrazed sites were higher in pastures than in natural grasslands. Grazing increases soil N and SOC for natural grasslands in temperate regions. Our findings suggest that soil stoichiometric C:N:P stoichiometric signatures in grasslands differed between tropical and temperate regions on a global scale. P is a key element in regulation and restriction on soil C and N cycling in tropical regions but less in the temperate ones. Our findings suggest the direction of effects of grazing or grassland type on C:N:P stoichiometric signature. Since imbalances in soil stoichiometric ratios may have implications for ecosystem functioning, the assessment of these patterns could serve as a valuable tool for management and conservation of grasslands and pastures in both tropical and temperate regions.
more »
« less
Editorial for the Special Issue on Implantable Microdevices
Implantable microdevices, providing accurate measurement of target analytes in animals and humans, have always been important in biological science, medical diagnostics, clinical therapy, and personal healthcare [...]
more »
« less
- Award ID(s):
- 1808436
- PAR ID:
- 10177028
- Date Published:
- Journal Name:
- Micromachines
- Volume:
- 10
- Issue:
- 9
- ISSN:
- 2072-666X
- Page Range / eLocation ID:
- 603
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
In this paper, we investigated the seasonal and geomagnetic dependence of the auroral ‐region neutral winds and the tidal components between 90 and 125 km using nearly continuously sampled measurements from the Poker Flat Incoherent Scatter Radar (PFISR) from 2010 to 2019. The average winds show consistent semidiurnal oscillations between 100 and 115 km and diurnal oscillations above 115 km in all seasons with some seasonal and geomagnetic activity dependencies. In general, the semidiurnal oscillation in zonal and meridional directions is strongest in summer and weakest in winter. The diurnal oscillation is strongest in winter and weakest in spring. More details on the seasonal and geomagnetic activity dependencies are revealed in the tidal decomposition results. Tidal decomposition results show eastward mean wind below 115 km in summer, fall, and winter and westward mean wind above 115 km in all seasons. The meridional mean is northward below 115 km and southward above in all seasons. The diurnal amplitudes are small below 110 km and increase with altitude above 110 km in all seasons with larger enhancements in the meridional direction. The semidiurnal amplitudes increase with altitude below 110 km and reach a maximum at around 110 km, then decrease or keep stable (depending on the geomagnetic activity) above 110 km in both directions and all seasons. The diurnal phases shift to earlier times with the increase of geomagnetic activity but show different variations with altitudes in zonal and meridional directions. The semidiurnal phases show a downward progressing trend in both directions and in all seasons.more » « less
-
Metabolomics aims to achieve a global quantitation of the pool of metabolites within a biological system. Importantly, metabolite concentrations serve as a sensitive marker of both genomic and phenotypic changes in response to both internal and external stimuli. NMR spectroscopy greatly aids in the understanding of both in vitro and in vivo physiological systems and in the identification of diagnostic and therapeutic biomarkers. Accordingly, NMR is widely utilized in metabolomics and fluxomics studies due to its limited requirements for sample preparation and chromatography, its non‐destructive and quantitative nature, its utility in the structural elucidation of unknown compounds, and, importantly, its versatility in the analysis of in vitro, in vivo, and ex vivo samples. This review provides an overview of the strengths and limitations of in vitro and in vivo experiments for translational research and discusses how ex vivo studies may overcome these weaknesses to facilitate the extrapolation of in vitro insights to an in vivo system. The application of NMR‐based metabolomics to ex vivo samples, tissues, and biofluids can provide essential information that is close to a living system (in vivo) with sensitivity and resolution comparable to those of in vitro studies. The success of this extrapolation process is critically dependent on high‐quality and reproducible data. Thus, the incorporation of robust quality assurance and quality control checks into the experimental design and execution of NMR‐based metabolomics experiments will ensure the successful extrapolation of ex vivo studies to benefit translational medicine.more » « less
-
Do longer growing seasons give introduced plants an advantage over native plants in Interior Alaska?null (Ed.)In interior Alaska, increases in growing season length and rapid expansion of introduced species are altering the environment for native plants. We evaluated whether earlier springs, warmer summers, and extended autumns alter the phenology of leaves and flowers in native and introduced forbs and shrubs in the boreal understory and open-canopy habitats, and whether the responses provide an advantage to either group. We tracked the phenology of 29 native and 12 introduced species over three years with very different spring, summer, and autumn conditions. The native species produced flowers (but not leaves) earlier than the introduced species, and both groups advanced leaf-out and flowering in the early-snowmelt year. However, shifts in phenology between early and late years were similar for both groups. There was no increase in fruit development rate for either group in the warm summer. In contrast, in the year with the extended autumn, the introduced plants extended leaf production and time of senescence much more than native species. While growth form and leaf habit could explain the differences in phenology between native and introduced groups in spring and summer, these traits could not account for differences in autumn. We conclude that in boreal Alaska extended autumns may benefit introduced species more than native ones.more » « less
-
Abstract In developing countries in Africa and Asia, meeting challenges of water scarcity and pollution has often been hampered by shortcomings in higher education, including insufficient research productivity and funding, lack of opportunity for university graduates, and a mismatch between university activities and societal needs. To address these issues, we developed novel programs integrating technical instruction and preparation for professional practice in hydrology for cohorts of graduate students from Morocco and Egypt (2012–2013) and from Türkiye and Indonesia (2013–2014). Students participated in an initial online course and a follow‐up workshop featuring geographic information systems (GIS), remote sensing, and hydrologic modeling with internet‐based data sets. Field activities in the USA (first cohort) and in the students’ home countries (second cohort) included stream gauging, measurement of water levels in wells, water sampling, and measurement of hydrochemical parameters. A subsequent online course focused on research ethics, preparing proposals and publications, and presenting findings to technical audiences and the public, culminating in presentations at conferences in the USA. Participants mentored other students at their home institutions and at K‐12 schools in Türkiye and Indonesia. Participant feedback during and after the programs tended to be strongly positive, and participants have continued to engage with project leaders and mentor students in their home countries and the USA. Our modular, hybrid approach offers a template for students in hydrology and related fields to develop relevant skills and engage internationally.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/mi10090603
