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Climate warming alters subsoil but not topsoil carbon dynamics in alpine grassland

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Climate warming alters subsoil but not topsoil carbon dynamics in alpine grassland Juan Jia     Zhenjiao Cao     Chengzhu Liu     Zhenhua Zhang     Li Lin     Yiyun Wang     Negar Haghipour     Lukas Wacker     Hongyan Bao     Thorston Dittmar     Myrna J. Simpson     Huan Yang     Thomas W. Crowther     Timothy I. Eglinton     Jin‐Sheng He     Xiaojuan Feng Subsoil contains more than half of soil organic carbon (SOC) globally and is conventionally assumed to be relatively unresponsive to warming compared to the topsoil. Here, we show substantial changes in carbon allocation and dynamics of the subsoil but not topsoil in the Qinghai‐Tibetan alpine grasslands over 5 years of warming. Specifically, warming enhanced the accumulation of newly synthesized ( 14 C‐enriched) carbon in the subsoil slow‐cycling pool (silt‐clay fraction) but promoted the decomposition of plant‐derived lignin in the fast‐cycling pool (macroaggregates). Thes
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The concurrent decline of soil lead and children’s blood lead in New Orleans

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The concurrent decline of soil lead and children’s blood lead in New Orleans Howard W. Mielke ,  Christopher R. Gonzales ,  Eric T. Powell ,  Mark A. S. Laidlaw ,  Kenneth J. Berry ,  Paul W. Mielke  Jr. , and  Sara Perl Egendorf PNAS  first published October 14, 2019  https://doi.org/10.1073/pnas.1906092116 Significance The inextricable link between topsoil lead (Pb) and children’s blood lead (BPb) has not been widely accepted. Pb is associated with multiple health adversities. Urban residents are at risk from exposure to legacy Pb dust in topsoil resulting from smelting, industrial discharges, leaded gasoline emissions, leaded paint, and incineration. In New Orleans, topsoil median Pb decreased in ∼15 y from 99 mg/kg to 54 mg/kg, or ∼2.4 mg⋅kg⋅y −1 . In ∼12 y, children’s median BPb declined from 3.6 μg/dL to 1.3 μg/dL, or ∼0.2 μg⋅dL⋅y −1 . We argue that depletion of topsoil Pb is an important factor in the continuous decline of children’s BPb. Similar processes ar
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Biogeographic patterns in below-ground diversity in New York City’s Central Park are similar to those observed globally

Kelly S. Ramirez1 , Jonathan W. Leff4,5, Albert Barbera´n5 , Scott Thomas Bates6 , Jason Betley7 , Thomas W. Crowther8 , Eugene F. Kelly2 , Emily E. Oldfield8 , E. Ashley Shaw3 , Christopher Steenbock4 , Mark A. Bradford8 , Diana H. Wall1,3 and Noah Fierer4,5 Soil biota play key roles in the functioning of terrestrial ecosystems, however, compared to our knowledge of above-ground plant and animal diversity, the biodiversity found in soils remains largely uncharacterized. Here, they present an assessment of soil biodiversity and biogeographic patterns across Central Park in New York City that spanned all three domains of life, demonstrating that even an urban, managed system harbours large amounts of undescribed soil biodiversity. Despite high variability across the Park, below-ground diversity patterns were predictable based on soil characteristics, with prokaryotic and eukaryotic communities exhibiting overlapping biogeographic patterns. Further, Central Park soils harboured nearly
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20190711

Author  :  Darren S. Le Roux, Karen Ikin, David B. Lindenmayer, Adrian D. Manning, Philip Gibbons Year  : 2014 Title  :  The Future of Large Old Trees in Urban Landscapes Journal  :  PLOSone Comment   :   Large old trees have been defined as keystone ecological  structures in urban ecosystem. Once large old trees are removed, they can be extremely  difficult to replace in the short term because of the prolonged time  period needed for trees to mature.  Human activities such as land clearance, logging and livestock  grazing are responsible for the decline of large old trees.  However, few studies  have investigated the decline of large old trees in urban landscapes
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20190419

Author  :  Milind Bunyan, Shibu Jose, Robert Fletcher Year  : 2019 Title  :  Edge Effects in Small Forest Fragments: Why More Is Better? Journal  :  American Journal of Plant Sciences Comment   :   They investigated the response of microenvironment and edaphic variables to distance from a tropical montane forest (locally known as shola)-grassland edge using one-edge and multiple-edge models.   The edpahic variables did not show any differences between the grassland and shola soils. The conventional one-edge models sufficiently explained variation trends in micro environment along the edge to interior gradient in large fragments.   As with other studies on small fragments though, they observed no edge effects with the use of a conventional one-edge model. However, the inclusion of multiple edges in small fragments significantly improved model fit. Thus, small fragments dominated by edge habitat may in fact resemble larger fragments with the inclusion of multiple edge
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20190412

Author  :  Ian A. Smith, Lucy R. Hutyra, Andrew B. Reinmann1, Jonathan R. Thompson, David W. Allen Year  : 2019 Title  :  Evidence for edge enhancements of soil respiration in temperate forests Journal  :  Geophysical Research Letters Comment   :   Forest fragmentation impacts carbon uptake and storage, however, the magnitude and direction of fragmentation impacts on soil respiration remain poorly characterized. They quantify soil respiration rates along edge-to-interior transects in two temperate broad-leaf forests in the eastern US that vary in climate, species composition, and soil type. They observe average soil respiration rates 15-26% higher at the forest edge compared to the interior, corresponding to large gradients in soil temperature.  These results suggest that estimates of soil respiration in the temperate forest region may be underestimating biological emissions of carbon dioxide.
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20190405

Author  :  Moura-Bueno, J. M. Dalmolin, R. S. D. ten Caten, A. Dotto, A. C. Dematte, J. A. M. Year  : 2019 Title  :  Stratification of a local VIS-NIR-SWIR spectral library by homogeneity criteria yields more accurate soil organic carbon predictions Journal  :  Geoderma Comment   :    The aim of this research was to  i) characterize and identify differences among spectra obtained for subtropical soils samples, ii)  evaluate different pre-processing techniques and multivariate methods to propose SOC prediction models from  the spectral data and iii) evaluate the performance of SOC prediction models calibrated from the stratification of  a local library.  Spectral reflectance measurements were performed in the  laboratory with a spectroradiometer in the range of 350–2500 nm. Six pre-processing techniques were applied to  the spectra (including derivatives, normalization and non-linear transformations) and four multivariate calibration  methods, namely, partial least
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