Variation of bacteria biomass and its possible controlling factors in the East China Sea     

Wenjuan Xia  Jiangtao Wang  Liju Tan  Qiulu Wang 《中国海洋大学学报(英文版)》2011,10(2):135-141

Two surveys were performed for determining bacteria biomass (BB), temperature, salinity, chlorophyll a (chl-a) and nutrient concentrations at 11 stations with three sampling depths in the high-incidence regions of red tide in the East China Sea (ECS) in the spring of 2006. Temperature and salinity increased from nearshore to offshore region and from high latitude to low latitude in the two cruises of 2006. BB were between 0.3–5.2 mgC m⁻³ (about 2.1 mgC m⁻³ on average) and 0.2–6.0 mgC m⁻³ (about 2.7 mgC m⁻³ on average) respectively in the two cruises. BB in the surface layer decreased from the Changjiang River estuary to high sea and from low latitude to high latitude. The results showed that bacterial growth was regulated by temperature, primary production and inorganic nutrient concentrations depending on different hydrographic conditions. In the surface and middle layers where the primary production can supply enough organic substrate, temperature was the main factor to control bacteria biomass. BB showed a good correlation between the surface and middle layers in both cruises. The distribution of nutrients during both cruises showed a similar decreasing trend from nearshore region and high latitude to offshore region and low latitude. High BB values were mainly recorded from samples in the middle layer where chl-a concentrations were also high, indicating primary production being strongly correlated with temperature over the ECS shelf. In the offshore area, phosphate and silicate became limiting factors for phytoplankton growth with indirect influence on BB. Bacteria played an important role in nitrogen regeneration process turning organic nitrogen to inorganic forms such as NH₄ ⁺. The increasing ratio of NH₄ ⁺/DIN could be a proof of that.  相似文献   

Deep-water carbonate concentrations in the southwest Pacific     

Helen C. Bostock  Bruce W. HaywardHelen L. Neil  Kim I. CurrieGavin B. Dunbar 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(1):72-85

We have compiled carbonate chemistry and sedimentary CaCO₃% data for the deep-waters (>1500 m water depth) of the southwest (SW) Pacific region. The complex topography in the SW Pacific influences the deep-water circulation and affects the carbonate ion concentration ([CO₃2−]), and the associated calcite saturation horizon (CSH, where ??_calcite=1). The Tasman Basin and the southeast (SE) New Zealand region have the deepest CSH at ∼3100 m, primarily influenced by middle and lower Circumpolar Deep Waters (m or lCPDW), while to the northeast of New Zealand the CSH is ∼2800 m, due to the corrosive influence of the old North Pacific deep waters (NPDW) on the upper CPDW (uCPDW). The carbonate compensation depth (CCD; defined by a sedimentary CaCO₃ content of <20%), also varies between the basins in the SW Pacific. The CCD is ∼4600 m to the SE New Zealand, but only ∼4000 m to the NE New Zealand. The CaCO₃ content of the sediment, however, can be influenced by a number of different factors other than dissolution; therefore, we suggest using the water chemistry to estimate the CCD. The depth difference between the CSH and CCD (??Z_CSH−CCD), however, varies considerably in this region and globally. The global ??Z_CSH−CCD appears to expand with increase in age of the deep-water, resulting from a shoaling of the CSH. In contrast the depth of the chemical lysocline (??_calcite=0.8) is less variable globally and is relatively similar, or close, to the CCD determined from the sedimentary CaCO₃%. Geochemical definitions of the CCD, however, cannot be used to determine changes in the paleo-CCD. For the given range of factors that influence the sedimentary CaCO₃%, an independent dissolution proxy, such as the foraminifera fragmentation % (>40%=foraminiferal lysocline) is required to define a depth where significant CaCO₃ dissolution has occurred back through time. The current foraminiferal lysocline for the SW Pacific region ranges from 3100-3500 m, which is predictably just slightly deeper than the CSH. This compilation of sediment and water chemistry data provides a CaCO₃ dataset for the present SW Pacific for comparison with glacial/interglacial CaCO₃ variations in deep-water sediment cores, and to monitor future changes in [CO₃2−] and dissolution of sedimentary CaCO₃ resulting from increasing anthropogenic CO₂.  相似文献   

土壤碳循环研究进展及干旱区土壤碳循环研究展望   总被引：5，自引：1，他引：4  

许文强  陈曦  罗格平  蔺卿 《干旱区地理》2011,(4)

土壤碳库动态及其驱动机制是陆地生态系统碳循环与全球变化研究的热点问题之一。随着各国对《京都议定书》的重视,农业土壤碳库变化及其源汇效应研究不断加强,但以往研究土壤碳循环主要是针对有机碳,较少考虑无机碳的作用和地位,干旱区土壤无机碳储量巨大,其在区域碳循环过程中的贡献日益显著,这使得干旱区土壤碳循环研究必须同时考虑土壤有机碳和无机碳的行为。国内外关于农业土壤有机碳动态的研究主要围绕农业土壤有机碳储量、固碳潜力等问题展开,研究区多为湿润、半湿润地区;国际上对农业土壤无机碳动态的研究主要集中在干旱区土地管理措施对土壤发生性碳酸盐碳的形成与转化方面,研究方法以稳定同位素技术为主,但目前关于中国干旱区农业土壤无机碳动态的研究还较为薄弱。因此,应加强干旱区绿洲土壤碳循环研究,深入分析干旱区绿洲土壤碳的源/汇效应;探讨土壤无机碳动态变化的机理。  相似文献   

Association of phosphate with rhyolite glass in marine Neogene tuffs from Patagonia,Argentina     

Nora Rubinstein  Ana M. Fazio  Roberto A. Scasso  Steven Carey 《Sedimentology》2013,60(4):1007-1016

The precipitation/replacement of Ca‐phosphate is a complex process that commonly takes place during the early diagenesis in marine sediments. The unusual occurrence of shallow marine, early diagenetic phosphatic deposits associated with glassy tuffs in the Neogene Gaiman Formation, in the Chubut Province, Patagonia, Argentina, constitutes a good case example for the study of replacement and precipitation of Ca‐phosphate on an unstable substrate. Isocon diagrams illustrate that chemical changes during glass diagenesis include gains in loss on ignition and Ca, and losses of K. These changes are the result of glass hydration during sea water–glass interaction, together with adsorption and diffusion of ions into the bulk shard; combined, these represent an incipient process of volcanic glass replacement by Ca‐phosphate. Subsequent early diagenetic P enrichment in the pore solutions led to phosphate precipitation, associated with pitting on the glass shards and pumice. The associated development of a reactive surface promoted the incorporation of P and Ca into their margins. Lastly, precipitation of calcium phosphate filled the vesicles and other open cavities, inhibiting further glass dissolution. The high porosity and reactivity of the volcanic glass provided an appropriate substrate for phosphate precipitation, leading to the development of authigenic apatite concretions in the volcanic‐glass bearing strata of the Gaiman Formation. This research is of significance for those concerned with marine phosphatic deposits and sheds light on the processes of early diagenetic phosphate precipitation by replacement of an atypical, unstable substrate like hydrated volcanic glass.  相似文献   

植物样品中无机元素分析的样品前处理方法和测定技术   总被引：11，自引：5，他引：6  

刘亚轩  李晓静  白金峰  马娜  张勤 《岩矿测试》2013,32(5):681-693

植物样品中无机元素的分析测定在环境地球化学和生物地球化学的研究中起着重要作用。植物样品中元素含量一般较低,须选用科学合理的前处理技术和灵敏度高、精密度好、检出限低的测定方法。本文针对植物样品前处理方法和无机元素分析测定技术的研究进展、优势与不足进行评述。前处理方法主要根据样品和待测元素的性质进行选择:干法灰化所用试剂少、空白值低,但组织致密型的样品不易灰化完全、高温下易造成元素挥发损失;湿法消解样品消解较为完全,但试剂消耗大、空白值高、操作繁琐;微波消解可以防止部分易挥发元素损失,用酸量少、消解速度快,但称样量相对较小,不适于需要大称样量的样品分析。几乎所有针对元素分析的仪器分析技术都可以用于植物样品分析,主要根据仪器适用的元素、必要的干扰校正以及基体改进等方面进行选择:电感耦合等离子体质谱法可同时测定植物样品中40种以上的元素,高分辨质谱的检出限可达fg/mL;电感耦合等离子体发射光谱法适用于某些植物样品中含量较高的P、K、Na等元素的测定;原子吸收光谱法可分析元素达70余种,是普及程度最高的仪器分析技术之一;原子荧光光谱法与氢化物发生技术的联用,在元素含量较低的植物样品分析中技术优势更加明显;新兴的激光诱导击穿光谱技术已被应用于植物样品分析,无需复杂的样品前处理,操作简单快速,可实现原位、在线、实时、多元素同时检测;其他选择性强、灵敏度高的分析技术,满足了一些特定元素不能用常规分析技术测定的需求。当前主流分析技术的样品前处理方法都存在着缺陷,固体进样技术将成为植物样品分析领域的发展方向之一。  相似文献   

中国石油地质学创新发展论评     

崔永强  于晶  王丽丽 《化工矿产地质》2013,(4):242-247,254

石油地质学是国家石油战略的组成部分,是国家石油安全的组成部分,必须予以高度重视。石油地质学来源于实践。但随着石油勘探开发实践的不断深入,仅仅依靠归纳和总结来自实践的认识已经无法满足人们对石油地质学在科学层面的理解和掌握。从沉积层获得的有关构造、生油、储层方面的知识无法全面解释在结晶基底和火山岩中发育油气藏的事实,而最新揭示出金属、非金属矿床、油气藏与深部构造和深部流体存在密切关系,为我们发展石油地质学提供了崭新的思路。欧洲惠更斯号探测器发现土卫六上存在甲烷湖的事实告诉我们,石油地质学的不仅仅是地质学问题,更是天文学问题。所以,及时吸收消化各学科最新成果,创新发展中国石油地质学,已是保障国家石油安全的当务之急。  相似文献   

沉积盆地、结晶基底和油、气成因理念与第二深度空间勘探和开发   总被引：10，自引：2，他引：8       下载免费PDF全文

滕吉文  阮小敏  张永谦  闫雅芬 《地球物理学报》2009,52(11):2798-2817

在石油、天然气的勘探和开发研究中,涉及到深部空间的介质、结构和属性,在沉积建造上涉及到陆相沉积、海相沉积和火山岩相,在油、气成因理论上涉及到有机成因和无机成因,在机制上涉及到深部流体的分异、调整、运移和动力作用.这些本质性问题的研究和探讨是人们十分关注的科学领域.基于油、气生、储和形成的理论、应用和成效的研究提出,有几个基础性的理念问题必须重新认识,特别是沉积建造与古老变质岩结晶基底;双相（海相和陆相）沉积建造与盆地的内涵和双基（有机和无机）混合油、气成因理念.清晰地厘定这些认识不仅有益于对油、气形成、聚集和勘探及开发给出一个更为科学的深部空间,即第二深度空间（5000~10000 m）的油、气勘探,而更为重要的是基于对这些理念的重新认识和深化研究可构建新的思路或理论,且在新的理念导向下,强化油、气深部勘探,以期能在理论研究和实践应用中取得新的成效,发现大型与超大型油、气田.  相似文献   

新型复合胶无粘土冲洗液研究及应用     

吴飞  陈礼仪  朱宗培  费立  吴丽 《煤田地质与勘探》2003,31(5):57-59

针对松散覆盖层、强风化破碎层取心率低,岩心松散破碎,孔壁稳定性差等问题,进行了以天然植物胶为主原料的处理剂复配改性研究和冲洗液优化配方研究。主要研究方法是通过有机聚合物和无机交联剂的作用,对羟丙基瓜尔胶(GRJ)进行交联改性,以此获得新型复合胶无粘土冲洗液优化配方,并进行了现场应用。应用效果表明,该冲洗液密度低,粘度可调范围大,流变性和润滑性好,成膜护心、护壁作用强,完全满足第四系覆盖层、胶结差的砂卵石层和强风化破碎地层取心钻进要求。   相似文献   

长江口潮滩沉积物－水界面无机氮交换通量   总被引：11，自引：1，他引：10  

陈振楼  王东启  许世远  张兴正  刘杰 《地理学报》2005,60(2):328-336

对长江口滨岸潮滩7个典型断面三态氮的界面交换通量进行了三年多的季节性连续观测,结果表明无机氮的界面交换行为存在复杂的空间分异和季节变化。NO^-₃-N和NH⁺₄-N的界面交换通量正负变化范围较大,分别介于-32.82~24.13 mmol.m^-2.d^-1和-18.45~10.65mmol.m^-2.d^-1之间;而NOsup>-₂-N的界面交换通量很小,仅为-1.15~2.82 mmol.m^-2.d^-1。NO^-₃-N的界面交换具有明显的上下游季节性时空分异特征,而NH⁺₄-N的界面交换则表现为南北岸季节性时空分异现象。盐度是控制长江口滨岸潮滩NH⁺₄-N界面交换行为的主要因素,而沉积物粒度、水体 NO^-₃-N浓度、沉积物有机质含量、水温和溶解氧含量则以不同的组合方式,共同制约着 NO^-₃-N在潮滩界面交换的时空分异格局。  相似文献   

黑龙江省达连河油页岩地球化学特征及成因探讨     

王世辉  陈春瑞  郑玉龙  刘胜英 《吉林大学学报(地球科学版)》2006,36(6):933-937

论述了达连河含煤段油页岩及油页岩段油页岩的地球化学特征,探讨了两套油页岩成因。这两套油页岩地球化学性质有很多相似之处,主要表现为油页岩都属于中熔或难熔的硅质灰分,SiO₂、Al₂O₃及Fe₂O₃含量很高;无机元素 Mn/Ti小于0.1,Sr/Ba为0.1～0.5,V/Ni为2.6～7.0;有机质类型以腐泥腐殖型为主,正构烷烃OEP值为1.55～3.67,具奇碳数优势,主峰碳为nC₂₃和C₂₉,Pr/Ph比值平均高达2.30,具强烈的姥鲛烷优势,Pr/nC₁₇比值为1.18～3.20,说明这两套油页岩都形成于淡水、近岸及弱氧化-弱还原的湖沼相沉积环境。但含煤段油页岩沉积时期高温、湿润的古气候条件下的喜湿植物面貌,使油页岩母质类型具有较多的富氢组分,这是造成两套油页岩品质差异的主要原因。  相似文献