Emerging technologies for in situ measurement of soil carbon     

Ronald J. Gehl  Charles W. Rice 《Climatic change》2007,80(1-2):43-54

Carbon sequestration in the terrestrial biosphere is critical to mitigating the increasing anthropogenic CO₂ content of the atmosphere. However, improved efficiency of methods for soil C measurement is important to better estimate terrestrial C inventories and fluxes at a regional and global scale. Laboratory based measurement of soil C involves intensive, time consuming, and costly methodology that limits applicability for large land areas. Recently, research efforts have focused on measuring soil C in situ using a variety of methods. These methods include Laser Induced Breakdown Spectroscopy (LIBS), Inelastic Neutron Scattering (INS), near-infrared spectroscopy (NIRS), and remote sensing. Basic fundamentals of each of these in situ methods for soil C determination are presented, and the differences among the methods and their relative advantages and disadvantages are discussed.  相似文献   

Predicting the distribution of C3 (Festuca spp.) grass species using topographic variables and binary logistic regression model     

Charles Otunga  John Odindi  Onisimo Mutanga  Clement Adjorlolo  Jacobus Botha 《国际地球制图》2018,33(5):489-504

The spatial distribution of different C3 and C4 grass species in tropical montane areas is commonly influenced by a number of factors that include site-specific topography. Hence, the distribution of these grasses across topographic gradients can vary significantly. In this study, we investigate the influence of topographic factors (elevation, slope and aspect) on the spatial distribution of Festuca grass species in a commonage area, comprising agro-biodiversity conservation land use. Integration of the topographic variables using GIS and binary logistic regression (LR) modelling showed that C3, Festuca grass species distribution can be predicted or mapped with an accuracy of 80% in the landscape under study. The study contributes to understanding the spatial distribution of C3 grass species and provides valuable information for designing and optimizing rangeland conservation in the subtropical montane landscapes.  相似文献   

Strategies for Recording the Full Seismic Wavefield     

Robert Woodwar  Charles Langston  Justin Sweet  Kent Anderson 《《地质学报》英文版》2018,92(Z1):320-320

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Groundwater-pumping optimization for land-subsidence control in Beijing plain,China     

Qin  Huanhuan  Andrews  Charles B.  Tian  Fang  Cao  Guoliang  Luo  Yong  Liu  Jiurong  Zheng  Chunmiao 《Hydrogeology Journal》2018,26(4):1061-1081

Hydrogeology Journal - Beijing, in the North China plain, is one of the few megacities that uses groundwater as its main source of water supply. Groundwater accounts for about two-thirds of the...  相似文献   

Don’t Blame It on the Moonlight: Abiotic Drivers of Reproductive Development in an Estuarine-Dependent Prawn     

Caitlin L. Young  Iain M. Suthers  Daniel D. Johnson  Charles A. Gray  Faith A. Ochwada-Doyle 《Estuaries and Coasts》2018,41(2):444-452

Lunar phase is regarded as a key driver of reproductive development and spawning activity in prawns, but across smaller-temporal scales, other processes may have a significant influence. Here, we examined the effects of lunar phase and other abiotic variables on the reproductive development of an estuarine-dependent prawn, Metapenaeus bennettae Racek & Dall. We found that turbidity, salinity, water temperature and lunar phase each had a significant independent influence on the likelihood of female prawns being ripe throughout the spawning period. The likelihood of catching a ripe female increased on the new moon and first quarter of the moon and also during conditions of low turbidity, high salinity and high water temperature. For male prawns, however, significant interactions between salinity and lunar phase and also between turbidity and lunar phase were detected. These interactions indicated that salinity and turbidity have variable effects among the different lunar phases. Such complex relationships of reproductive timing and spawning success of M. bennettae, and potentially other aquatic species, are most likely adaptive responses to the highly variable conditions of estuarine environments.  相似文献   

Hydro-economic analysis of groundwater pumping for irrigated agriculture in California’s Central Valley,USA     

Josué Medellín-Azuara  Duncan MacEwan  Richard E. Howitt  George Koruakos  Emin C. Dogrul  Charles F. Brush  Tariq N. Kadir  Thomas Harter  Forrest Melton  Jay R. Lund 《Hydrogeology Journal》2015,23(6):1205-1216

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Evaluation of the use of a commercially available cavity ringdown absorption spectrometer for measuring NO2 in flight,and observations over the Mid-Atlantic States,during DISCOVER-AQ     

L. C. Brent  W. J. Thorn  M. Gupta  B. Leen  J. W. Stehr  H. He  H. L. Arkinson  A. Weinheimer  C. Garland  S. E. Pusede  P. J. Wooldridge  R. C. Cohen  R. R. Dickerson 《Journal of Atmospheric Chemistry》2015,72(3-4):503-521

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Bay breeze influence on surface ozone at Edgewood,MD during July 2011     

Ryan M. Stauffer  Anne M. Thompson  Douglas K. Martins  Richard D. Clark  Daniel L. Goldberg  Christopher P. Loughner  Ruben Delgado  Russell R. Dickerson  Jeffrey W. Stehr  Maria A. Tzortziou 《Journal of Atmospheric Chemistry》2015,72(3-4):335-353

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Ocean acidification and photic‐zone anoxia at the Toarcian Oceanic Anoxic Event: Insights from the Adriatic Carbonate Platform     

Nicholas P. Ettinger  Toti E. Larson  Charles Kerans  Alyson M. Thibodeau  Kelly E. Hattori  Sean M. Kacur  Rowan C. Martindale 《Sedimentology》2021,68(1):63-107

Severe global climate change led to the deterioration of environmental conditions in the oceans during the Toarcian Stage of the Jurassic. Carbonate platforms of the Western Tethys Ocean exposed in Alpine Tethyan mountain ranges today offer insight into this period of environmental upheaval. In addition to informing understanding of climate change in deep time, the effect of ancient carbon cycle perturbations on carbonate platforms has important implications for anthropogenic climate change; the patterns of early Toarcian environmental deterioration are similar to those occurring in modern oceans. This study focuses on the record of the early Toarcian Oceanic Anoxic Event (ca 183.1 Ma) in outcrops of the north‐west Adriatic Carbonate Platform in Slovenia. Amidst environmental deterioration, the north‐west Adriatic Platform abruptly transitioned from a healthy, shallow‐water environment with diverse metazoan ecosystems to a partially drowned setting with low diversity biota and diminished sedimentation. An organic carbon‐isotope excursion of ?2.2‰ reflects the massive injection of CO₂ into the ocean‐atmosphere system and marks the stratigraphic position of the Toarcian Oceanic Anoxic Event. A prominent dissolution horizon and suppressed carbonate deposition on the platform are interpreted to reflect transient shoaling of the carbonate compensation depth to unprecedentedly shallow levels as the dramatic influx of CO₂ overwhelmed the ocean’s buffering capacity, causing ocean acidification. Trace metal geochemistry and palaeoecology highlight water column deoxygenation, including the development of photic‐zone anoxia, preceding and during the Toarcian Oceanic Anoxic Event. Ocean acidification and reduced oxygen levels likely had a profoundly negative effect on carbonate‐producing biota and growth of the Adriatic Platform. These effects are consistent with the approximate doubling of the concentration of CO₂ in the ocean‐atmosphere system from pre‐event levels, which has previously been linked to a volcanic triggering mechanism. Mercury enrichments discovered in this study support a temporal and genetic link between volcanism, the Toarcian Oceanic Anoxic Event and the carbonate crisis.  相似文献   

Economic value of tropical cyclone conditions of readiness     

Gulati  Sneh  Sampson  Charles R. 《Natural Hazards》2021,108(2):1687-1700

Natural Hazards - U. S. Military bases are especially vulnerable to tropical cyclones (TCs) because they concentrate extremely expensive equipment in a small area. A TC hit at a base can result in...  相似文献