Specific affinity for phosphate uptake and specific alkaline phosphatase activity as diagnostic tools for detecting phosphorus-limited phytoplankton and bacteria     

Tsuneo Tanaka  Peter Henriksen  Risto Lignell  Kalle Olli  Jukka Seppälä  Timo Tamminen  T. Frede Thingstad 《Estuaries and Coasts》2006,29(6):1226-1241

We analyzed responses of soluble reactive phosphorus (SRP), bioavailable phosphate (PO₄), particulate phosphorus, turnover time of orthophosphate (T_t), and alkaline phosphatase activity (APA) to varying degrees of nutrient stress. The nutrient stress was evoked by different treatments in concentration and combination of inorganic nitrogen (N) and phosphorus (P), and labile organic carbon (glucose) to mesocosms in experiments carried out in eutrophic southern (Odense Fjord, Denmark) and northern (Tvärminne Archipelago, Finland) coastal zones of the Baltic Sea. Despite seasonal and geographical differences, similar responses were observed in both experiments. Low SRP (<100 nmol l^?1), shortT _t (<10 h), and increased levels of APA were observed in both N+P balanced and P deficient treatments, while the opposite trend was observed in P replete treatments. The shortestT _t and the highest APA were found when glucose was combined with N treatment. Bioavailable PO₄ was estimated usingT _t and P uptake rates as derived from stoichiometric conversion of carbon based primary and bacterial production. With shorterT _t, the PO₄ pool declined to <1 nmol-P l^?1, whereas the SRP background pool (difference between SRP and PO₄) remained relatively constant (c. 50 nmol l^?1). APA was inversely related to PO₄ but not to SRP. Responses of specific APA and specific affinity for PO₄ uptake, which are APA and PO₄ uptake rates (inverse ofT _t), respectively, normalized to the summed P biomass of phytoplankton and bacteria, responded consistently to the pattern and magnitude of nutrient limitation evoked in our experiments. Our results, together with a literature survey, suggest that both parameters can be useful in examining PO₄ availability for the natural phytoplankton and bacteria community in P starved aquatic systems.  相似文献   

超宽频带观测应用研讨会在北京召开     

吕永清 《国际地震动态》2007,(10):44-45

2007年9月26日,中国地震局监测预报司在北京主持召开了“超宽频带观测应用研讨会”。出席研讨会的监测预报司领导有监测预报司司长李克,处长余书明,余书明处长主持会议。中国工程院院士许绍燮到会演讲。会议承办方中国地震局地震研究所所长姚运生到会致词,龚平副所长到会。出席  相似文献   

Evaluation of Genetic Diversity in Zostera japonica (Aschers. et Graebn.) for Seagrass Conservation in Brackish Lower Reaches of the Hii River System, Japan     

Yoshikuni Hodoki  Kako Ohbayashi  Norio Tanaka  Hidenobu Kunii 《Estuaries and Coasts》2013,36(1):127-134

This study examined the genetic diversity and composition of 15 populations of Zostera japonica in the Hii River system, Japan. Genetic and genotypic diversity were consistently higher in populations in the Ohashi River than those in Lake Nakaumi, and the local tidal movements may explain the observed patterns of genetic diversity. Pairwise fixation index values among the populations in Lake Nakaumi were higher than among those in the Ohashi River, even though the ranges of the distances among the populations in the two locations were almost the same. The gene flow from the Ohashi River populations was important for some populations in Lake Nakaumi. The low genotypic diversity and gene flow in Lake Nakaumi seemed similar to those of marginal populations. If this low genotypic diversity and genetic differentiation were partly caused by human activities, the promotion of gene flow should be taken into account in conserving the populations in Lake Nakaumi.  相似文献   

Impacts of pollution on coastal and marine ecosystems including coastal and marine fisheries and approach for management: a review and synthesis   总被引：2，自引：0，他引：2  

Shahidul Islam M  Tanaka M 《Marine pollution bulletin》2004,48(7-8):624-649

The history of aquatic environmental pollution goes back to the very beginning of the history of human civilization. However, aquatic pollution did not receive much attention until a threshold level was reached with adverse consequences on the ecosystems and organisms. Aquatic pollution has become a global concern, but even so, most developing nations are still producing huge pollution loads and the trends are expected to increase. Knowledge of the pollution sources and impacts on ecosystems is important not only for a better understanding on the ecosystem responses to pollutants but also to formulate prevention measures. Many of the sources of aquatic pollutions are generally well known and huge effort has been devoted to the issue. However, new concepts and ideas on environmental pollution are emerging (e.g., biological pollution) with a corresponding need for an update of the knowledge. The present paper attempts to provide an easy-to-follow depiction on the various forms of aquatic pollutions and their impacts on the ecosystem and organisms.  相似文献   

Efficiency of neutrino-induced radio measurements to inspect local areas of Enceladus     

D. Shoji  K. Kurita  H.K.M. Tanaka 《Icarus》2012,218(1):555-560

The Cassini probe observed a young and smooth surface around the south pole of Enceladus, while around the north pole the surface was found to be relatively old and inactive (Porco, C.C. et al. [2006]. Science 311, 1393–1401). This heterogeneous surface implies that the ice thickness of Enceladus is not uniform between the north and south polar regions. Determining the thickness of the icy layer is important to confirm the existence of an internal ocean as well as to reveal the heating mechanism of Enceladus. We show that the measurement of radio waves induced by cosmic neutrinos can be an effective method to constrain the ice thickness of a localized area where conventional gravity or electromagnetic field measurements cannot be used. This method could be used to constrain the thickness of the icy layer on Enceladus even if the ice is a few tens of kilometers thick, measuring over a period of several years, which greatly exceeds the ability of radar sounding, and hence could be used in future orbiter missions.  相似文献   

初始场与云微物理参数方案在飑线数值模拟中的对比研究     

张弛  王咏青  廖玥  沈新勇  李小凡 《高原气象》2019,(2):410-420

采用CM1模式以200 m的高精度水平网格距对一次东北冷涡下的飑线过程进行模拟,采用1 km的水平网格距进行对比试验探究网格距的影响,并通过探空资料的替换与修改研究不稳定能量和垂直风切变对飑线发展的影响。研究表明,水平网格距增大主要使系统演变减缓,强度也有一定的减弱;初始场的不稳定能量减小会使飑线减弱明显,直至无法生成;垂直风切变对飑线的形成影响较小,主要改变了飑线的结构,没有垂直风切变时形成的飑线更为松散。最后的敏感性试验研究了7种云微物理参数方案对飑线内水粒子分布的影响,发现不同的云微物理参数方案会使水粒子的含量和分布出现变化,进一步影响固、液态的降水,飑线模拟采用的NA方案高层冰和雪含量最高,但由于雨和降落到地表的雹、霰含量低,使得累计降水量最小。  相似文献   

Mechanism and future risk of slope instability induced by extreme rainfall event in Izu Oshima Island,Japan     

Towhata  Ikuo  Goto  Satoshi  Goto  Shigeru  Akima  Takeshi  Tanaka  Junya  Uchimura  Taro  Wang  Gonghui  Yamaguchi  Hiroshi  Aoyama  Shogo 《Natural Hazards》2021,105(1):501-530

Natural Hazards - A volcanic slope in Izu Oshima Island in Japan experienced a profound rain-induced disaster in October 2013. Since this slope had been stable for centuries except for minor...  相似文献   

个旧老厂Sn-Cu矿床内外接触带矿体原生晕分带与深部矿体预测模型     

朱旭  杨融  陈永清  王连月  李刚 《地学前缘》2021,28(3):112-127

矿床的原生晕通常形成在矿体周围,与蚀变矿物和矿石矿物同时形成。矿床原生晕的分带规律能够提供较为准确的找矿目标。一些金属矿床的原生晕具有示踪隐伏矿体的作用,从而为探测深埋矿体提供了重要的线索。老厂大型锡多金属矿床是个旧巨型锡多金属矿床的重要组成部分,以广泛发育夕卡岩化矿化为其特征。根据其空间分布夕卡岩矿化可分为两类:内夕卡岩矿化和外夕卡岩矿化。前者发生在侵入体内蚀变带,后者主要形成于侵入体附近的蚀变碳酸盐岩中。它们在地球化学特征上有以下异同:(1)内夕卡岩和外夕卡岩矿体的轴向分带序列(从矿体的头部到尾部)分别为Ag-As-Bi-Cu-F-Pb-Sn-Zn-B→Ba-Co-Cr-Ni-Sb-V→Be-Mo-W和F-B-Ba-W→Cu-Sb-Be-Cr→Sn-Pb-Zn-Ni-Ag→Co-Mo-Bi-As。这表明异常元素的种类具有高度一致性,但轴向分带序列存在很大差异。(2)统计分析表明内夕卡岩矿化具有三种主要成矿元素组合:(a)As-B-Be-Co-Sn组合代表发育在花岗岩内蚀变带的云英岩化有关的锡石-硫化物-电气石蚀变矿化组合;(b)Mo-W代表与高温夕卡岩化相关的辉钼矿-白钨矿矿化组合;(c)Ag-Pb-Cu-Zn代表后期叠加于内蚀变带角银矿-方铅矿-闪锌矿-黄铜矿矿化组合。(3)外夕卡岩矿化也具有三种主要成矿元素组合:(a)Ag-Bi-Sn-Cu代表发育在外夕卡岩带角银矿-辉铋矿-黄锡矿(锡石)-黄铜矿中低温矿化组合;(b)As-Zn-Pb代表发育在外夕卡岩带毒砂-闪锌矿-方铅矿中温硫化物组合;(c)F-Be-W-Mo代表靠近侵入体一侧萤石-绿柱石-白钨矿-辉钼矿高温矿化组合。上述表明矿化具有多期多阶段特点。最后,在原生晕轴向分带序列的基础上,分别建立了内、外夕卡岩带深部矿体预测模型,为深部成矿预测提供强有力工具。  相似文献   

Decision-theoretic sensitivity analysis for reservoir development under uncertainty using multilevel quasi-Monte Carlo methods     

Takashi Goda  Daisuke Murakami  Kei Tanaka  Kozo Sato 《Computational Geosciences》2018,22(4):1009-1020

At various stages of petroleum reservoir development, we encounter a large degree of geological uncertainty under which a rational decision has to be made. In order to identify which parameter or group of parameters significantly affects the output of a decision model, we investigate decision-theoretic sensitivity analysis and its computational issues in this paper. In particular, we employ the so-called expected value of partial perfect information (EVPPI) as a sensitivity index and apply multilevel Monte Carlo (MLMC) methods to efficient estimation of EVPPI. In a recent paper by Giles and Goda, an antithetic MLMC estimator for EVPPI is proposed and its variance analysis is conducted under some assumptions on a decision model. In this paper, for an improvement on the performance of the MLMC estimator, we incorporate randomized quasi-Monte Carlo methods within the inner sampling, which results in an multilevel quasi-Monte Carlo (MLQMC) estimator. We apply both the antithetic MLMC and MLQMC estimators to a simple waterflooding decision problem under uncertainty on absolute permeability and relative permeability curves. Through numerical experiments, we compare the performances of the MLMC and MLQMC estimators and confirm a significant advantage of the MLQMC estimator.  相似文献   

Spatiotemporal distribution of sea-island prehistoric dune sites,Holocene sea levels,and aeolian sand activities in Fujian Province,China     

JIN Jianhui  LING Zhiyong  LI Zhizhong  ZUO Xinxin  FAN Xuechun  HUANG Yunming  WANG Xiaoyang  WEI Changfu  REN Yongqing  QIU Junjie 《地理学报(英文版)》2022,32(6):1157-1176

The lower reaches of the Minjiang River and its adjacent areas were among the most active prehistoric archaeological areas in Fujian Province. The accumulation types of Neolithic archaeological strata are roughly divided into dune sites and dune/shell mound sites. The sites can also be roughly divided into estuarine, coastal, and sea-island sites based on their geomorphic features. The cultural development of these prehistoric sites is of great significance for understanding the migration and spread of Austronesian civilization. Based on luminescence dating of typical Neolithic sites on Haitan Island, their quartz-OSL (optically stimulated luminecesence) burial ages were determined. Synthesizing previously published results, the temporospatial distribution characteristics of the sea-island sites on Haitan Island are discussed, and the relationship between Neolithic human activities and regional geomorphic processes is analyzed. The results show that: (1) the spatial and temporal distribution of the Haitan Island Neolithic sites are closely related to small-scale geomorphic features and are controlled by mesoscale geomorphic processes. The sites were mainly distributed in the foothills of two high hills along an NNE-SSW trend. With an increase in altitude, the features were distributed as “single site (I) - superimposed site - single site (II)” and appear successively. Single type sites (I) mainly appeared at low sea level, whereas single type sites (II) mainly appeared at high sea level. Superimposed sites were not subject to sea level changes. The relative elevation of the superimposed sites in the study area indicates the optimal residential area for human activities in the region. The single site with an elevation lower than the optimal residential area was mainly restricted by the lowest residential area, whereas the single site at a higher elevation than the optimal residential area was mainly affected by livelihood patterns. (2) High sea level caused by the “backwater effect” in low latitude areas in the southern hemisphere, and coastal aeolian sand activity influenced by sea level fluctuations in the middle Holocene correspond well with human activities recorded in the cultural stratigraphy of sea-island type sites. The altitude of coastal aeolian sand accumulation can be used as an indirect index to estimate the age of coastal dunes.  相似文献