Ocean urea fertilization for carbon credits poses high ecological risks     

Glibert PM  Azanza R  Burford M  Furuya K  Abal E  Al-Azri A  Al-Yamani F  Andersen P  Anderson DM  Beardall J  Berg GM  Brand L  Bronk D  Brookes J  Burkholder JM  Cembella A  Cochlan WP  Collier JL  Collos Y  Diaz R  Doblin M  Drennen T  Dyhrman S  Fukuyo Y  Furnas M  Galloway J  Granéli E  Ha DV  Hallegraeff G  Harrison J  Harrison PJ  Heil CA  Heimann K  Howarth R  Jauzein C  Kana AA  Kana TM  Kim H  Kudela R  Legrand C  Mallin M  Mulholland M  Murray S  O'Neil J  Pitcher G  Qi Y  Rabalais N  Raine R  Seitzinger S  Salomon PS  Solomon C 《Marine pollution bulletin》2008,56(6):1049-1056

The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.  相似文献   

A probabilistic seismic hazard assessment for the Turkish territory: part II—fault source and background seismicity model     

Mine Betül Demircioğlu  Karin Şeşetyan  Tamer Y. Duman  Tolga Çan  Senem Tekin  Semih Ergintav 《Bulletin of Earthquake Engineering》2018,16(8):3399-3438

Over the years, several local and regional seismic hazard studies have been conducted for the estimation of the seismic hazard in Turkey using different statistical processing tools for instrumental and historical earthquake data and modeling the geologic and tectonic characteristics of the region. Recently developed techniques, increased knowledge and improved databases brought the necessity to review the national active fault database and the compiled earthquake catalogue for the development of a national earthquake hazard map. A national earthquake strategy and action plan were conceived and accordingly with the collaboration of the several institutions and expert researchers, the Revision of Turkish Seismic Hazard Map Project (UDAP-Ç-13-06) was initiated, and finalized at the end of 2014. The scope of the project was confined to the revision of current national seismic hazard map, using the state of the art technologies and knowledge of the active fault, earthquake database, and ground motion prediction equations. The following two seismic source zonation models are developed for the probabilistic earthquake hazard analysis: (1) Area source model, (2) Fault and spatial smoothing seismic source model (FSBCK). In this study, we focus on the development and the characterization of the Fault Source model, the background spatially smoothed seismicity model and intrinsic uncertainty on the earthquake occurrence-rates-estimation. Finally, PSHA results obtained from the fault and spatial smoothed seismic source model are presented for 43, 72, 475 and 2475 years return periods (corresponding to 69, 50, 10, and 2% probability of exceedance in 50 years) for PGA and 5% damped spectral accelerations at 0.2 and 1.0 s.  相似文献   

Seismic hazard map of the Middle East     

Domenico Giardini  Laurentiu Danciu  Mustafa Erdik  Karin Şeşetyan  Mine B. Demircioğlu Tümsa  Sinan Akkar  Levent Gülen  Mehdi Zare 《Bulletin of Earthquake Engineering》2018,16(8):3567-3570

The collaborative project Earthquake Model of the Middle East (EMME, 2010–2015) brought together scientists and engineers from the leading research institutions in the region and delivered state-of-the-art seismic hazard assessment covering Afghanistan, Armenia, Azerbaijan, Cyprus, Georgia, Iran, Iraq, Jordan, Lebanon, Palestine, Pakistan, Syria and Turkey. Their efforts have been materialized in the first homogenized seismic hazard model comprising earthquake catalogues, mapped active faults, strong motions databank, ground motion models and the estimated ground motion values for various intensity measure types and relevant return periods (e.g. 475–5000 years). The reference seismic hazard map of the Middle East, depicts the mean values of peak ground acceleration with a 10% chance of exceedance in 50 years, corresponding to a mean return period of 475 years. A full resolution poster is provided with this contribution.  相似文献   

三轴不等应力场下剪切破裂趋势面方向探析          下载免费PDF全文

李俊英  李培良 《地学前缘》2009,16(1):261

文章在弹性力学和库仑-摩尔破裂理论基础上,用数学解析方法剖析三轴不等应力状态,以及三轴全拉、三轴全压和最大最小主应力一拉一压三种情况下,斜截面上剪应力与抗剪阻力之差——"剪切差函数"的极值。进而探讨了剪切破裂趋势面方向与三主应力轴,及岩石(体)内摩擦角φ和内聚力C的关系。给出了不同应力状态下发生剪切破裂面的可能方向。在全压状态下,剪切破裂趋势面与最大主压应力轴夹角γ=±(45°-φ/2),即共轭角χ=±(90°-φ)。在一拉一压状态下,±(45°-φ/2)≤γ≤±45°,具体数值视拉主应力与压主应力比值确定。以上三种不等主应力下的剪切破裂面都是平面,且平行于中间主应力轴。构造拉张力的存在是无可争议事实,通过一拉一压状态下剪切破裂面趋势面分析,给出了构造地质实践中为什么有时剪切面共轭角χ>±(90°-φ),甚至接近90°的理论分析。  相似文献   

Spatial distribution of climatic conditions from the Middle Eocene to Late Miocene based on palynoflora in Central,Eastern and Western Anatolia     

Mine Sezgül Kayseri-Özer 《Geodinamica Acta》2013,26(1-2):122-157

The continental climatic evolution of Anatolia has been reconstructed quantitatively for the last 45 million years using the coexistence approach. Although there were some regional effects, the Anatolian Cenozoic continental climate record correlated with the European climatic condition and the global oxygen isotope record from marine environments. From middle Eocene to late Miocene, continental warming in Anatolia was pronounced for inferred winter temperature and mean annual temperature as in Europe. Generally, the palaeoclimatic property of Anatolia resembles the European climatic changing and marine temperature changing based on the oxygen isotope record; however, climatic values of the terrestrial area in Anatolia are higher from Lutetian to Aquitanian and these values are lower than European values from Aquitanian to Tortonian. Correspondingly, Cenozoic climatic cooling in Anatolia is directly associated with an increase of seasonality, palaeogeographic position and terrestrial condition. Furthermore, mean annual precipitation values of Anatolia remained relatively stable during the Eocene–Oligocene; however, these values indicated changing throughout middle–late Miocene. Moreover, in this study, decline of abundance and variables for the mangrove and back mangrove palaeocommunities during the last 45 million years is recorded because of the decreasing of humidity, temperature and increasing of terrestrial condition.  相似文献   

地勘单位承办企业工作的几点经验     

陈建义 《化工矿产地质》2004,26(1):59-62

为提高市场竞争力,根据自身的特点,认真研究市场信息,抓准项目,是地勘单位承办 企业的基础。工作中重视人力资源的开发和合理配置,建立切实可行的管理制度,在管理工作中 综合运用多种激励机制,就可使企业在激烈的市场竞争中立于不败之地。  相似文献   

Probabilistic long-term reservoir operation employing copulas and implicit stochastic optimization     

&#;vila  Leandro  Mine  Miriam R. M  Kaviski  Eloy 《Stochastic Environmental Research and Risk Assessment (SERRA)》2020,34(7):931-947

Stochastic Environmental Research and Risk Assessment - This paper explores and combines implicit stochastic optimization (ISO) with copula functions to simulate long-term operating policies for a...  相似文献   

A Quartz-Carbonate Gold Deposit in North Margin of Sino-Korean Archean Craton     

QIU Xiaoping Institute of Geology  CAGS    Beijing  China LI Chundong  YANG Zhishan  WANG Jun Zhangjiakou Gold Mine    Xuanhua  Hebei Province  China 《Continental Dynamics》2000,(1)

1. IntroductionThe gold deposits in Archean greenstone belts are the most important gold resources in the world, and their wall rocks are low-grade metamorphic greenstones (greenschist facies or sub-greenschist facies metamorphism). The ore bodies always appear very large in scale. The Sino-Korean Archean craton was not so stable as in Canada, South Africa, Australia and Russia, and its Archean greenstone belts are much smaller and with high grade metamorphism, where the gold deposits are …  相似文献   

Preface     

M. Takeuti  J. -R. Buchler 《Astrophysics and Space Science》1993,210(1-2):ix-ix

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IAU Colloquium No. 134 nonlinear phenomena in stellar variability     

T. Hamada  M. Takeuti 《Astrophysics and Space Science》1993,210(1-2):vii-vii

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