Complexation of mercury by dissolved organic matter in surface waters of Galveston Bay, Texas

The chemical speciation of dissolved mercury in surface waters of Galveston Bay was determined using the concentrations of mercury-complexing ligands and conditional stability constants of mercury-ligand complexes. Two classes of natural ligands associated with dissolved organic matter were determined by a competitive ligand exchange-solvent solvent extraction (CLE-SSE) method: a strong class (L_s), ranging from 19 to 93 pM with an average conditional stability constant (K_HgLs) of 10²⁸, and a weak class (L_w) ranging from 1.4 to 9.8 nM with an average K_HgLs of 10²³. The range of conditional stability constants between mercury and natural ligands suggested that sulfides and thiolates are important binding sites for dissolved mercury in estuarine waters. A positive correlation between the estuarine distribution of dissolved glutathione and that of mercury-complexing ligands supported this suggestion. Thermodynamic equilibrium modeling using stability constants for HgL, HgCl_x, Hg(OH)_x, and HgCl(OH) and concentrations of each ligand demonstrated that almost all of the dissolved mercury (> 99%) in Galveston Bay was complexed by natural ligands associated with dissolved organic matter. The importance of low concentrations of high-affinity ligands that may originate in the biological system (i.e., glutathione and phytochelatin) suggests that the greater portion of bulk dissolved organic matter may not be important for mercury complexation in estuarine surface waters.     

水下自航式海洋观测平台技术发展研究

水下自航式海洋观测平台是一种新型海洋观测平台，主要用于无人、大范围、长时间水下环境监测，包括物理学参数、海洋地质学和地球物理学参数，海洋化学参数、海洋生物学参数及海洋工程方面的现场接近观测。其特点是：成本低，环境适应性强，可冲破人工潜水极限而进入现场进行接近观测，免除了ROV需要水面支援母船的累赘，减少作业经费，体积小，使用方便，便于布放回收；可根据水声信号摇控或预置程序控制，按要求进行相关项目观测；有自主动力，水下运行时间相对较长，有源噪声低，可进行隐弊观测，正是基于以上的优点，近几年颇得海洋环境监测和海军方面的青睐，本文介绍了国际上水下自动观测平台的发展历史和现状，提出了我国开展研究水下自动观测平台的重要性及研究的面容。     

利用X射线衍射测定单斜辉石中硬玉组分含量

硬玉是单斜辉石中十分重要的端元组分,是单斜辉石分类的主要基础。利用x射线衍射分析确定的硬玉组分含量计算式为Jd(％)=[A-2.235]×25.741,其中Jd为硬玉组分百分含量,A为2—Theta角为30°(d=2.97)时峰值的相对强度Ⅰ与半高宽的乘积,其计算误差仅6.32％。     

长岛养殖扇贝丰,欠原因的初步探讨

通过对长岛扇贝养殖环境两年(1989、1990)监测及历史资料的初步分析研究,得出了影响长岛养殖扇贝丰欠的主要因子有:1)长岛地区的降水量;2)海水中浮游植物含量;3)海水盐度。建立了适合长岛水域的模糊综合评判关系式用以综合评判长岛的扇贝养殖环境及其与养殖扇贝丰、欠之间的关系。     

青海钩虾配合饲料对罗非鱼两品系生长效果的研究

研究青海钩虾对罗非鱼两品系吉富罗非鱼和彩虹鲷生长的促进作用。实验用青海钩虾与面粉、麸皮和豆饼制成 5组 ( ～ )配合饲料及良种场原用饲料 ( 组 )饲育吉富罗非鱼和彩虹鲷 ,经2 5 d试验结果表明 :( 1)彩虹鲷增重效果以 组饲料最高 ,平均增重为 4 4 .9g,较大于 组的 4 3.1g;( 2 )所有钩虾饲料对彩虹鲷的增色效果都高于良种场的原用饲料 组 ,其中以饲料 组最高 ;( 3)饲料 I组饲育吉富罗非鱼平均增重为 4 4 g,高于 组的 4 0 .1g;( 4 )吉富罗非鱼和彩虹鲷比较则显示出吉富罗非鱼的增重率明显高于彩虹鲷而饵料系数又较低的结果。     

均匀土质边坡稳定性计算的一种新方法

根据土力学原理 ,推导出一种在不考虑渗流力的情况下 ,确定斜坡临界滑动面和计算斜坡稳定系数的新方法。介绍了该方法在若干土石方工程中的应用实例。     

威海地区高压岩石组合及其成因演化

利用矿物地质温压计估算变质高峰期温压条件、退变质作用温压条件。研究表明,本区为鲁苏构造带的北延部分,代表本区晚元古代华南陆块与华北陆块的碰撞及三叠纪华北陆块向华南陆块推覆事件的发生和演化。     

Molecular analysis of complete ssu to lsu rdna sequence in the harmful dinoflagellatealexandrium tamarense (korean isolate, HY970328M)

New PCR primers (N=18) were designed for the isolation of complete SSU to LSU rDNA sequences from the dinoflagellateAlexandrium tamarense. Standard PCR, employing each primer set selected for amplifications of less than 1.5 kb, successfully amplified the expected rDNA regions of A. tamarense (Korean isolate, HY970328M). Complete SSU, LSU rDNAs and ITS sequences, including 5.8S rDNA, were recorded at 1,800 bp, 520 bp and 3,393 bp, respectively. The LSU rDNA sequence was the first report inAlexandrium genus. No intron was found in the LSU rRNA coding region. Twelve D-domains within the LSU rDNA were put together into 1,879 bp (44.4% G+C), and cores into 1514 bp (42.8% G+C). The core sequence was significantly different (0.0867 of genetic distance, 91% sequence similarity) in comparison withProrocentrum micans (GenBank access. no. X16108). The D2 region was the longest in length (300 bp) and highly variable among the 12 D-domains. In a phylogenetic analysis using complete LSU rDNA sequences of a variety of phytoplankton,A tamarense was clearly separated with high resolution against other species. The result suggests that the sequence may resolve the taxonomic ambiguities ofAlexandrium genus, particularly of the tamarensis complex.     

天然热释光技术在海洋油气田勘查中的应用

沉积物热释光能有效地反映海洋环境下深部油气田引起的微弱放射性异常。热释光在不同的测试粒级、不同的岩性中的丰度不同，结果为粗粒级＞细粒级、砂岩＞粉砂质砂岩＞泥质粉砂岩＞泥岩。热释光也与部分金属元素含量有关，Ti、Ba、Zn、Fe^3 /Fe^2 与热释光呈正相关关系。热释光与烃类也呈较强的正相关性。不同采用深度热释光测量结果表明，热释光剂量随沉积物的沉积深度和沉积时间的增加而增加，深层样的热释光对油气藏的指示效果更好。     

我国陆上大中型气田分布规律与有利勘探区带优选

“八五”、“九五”期间我国天然气探明储量幅度增长,大中型气田分布规律的深化研究密切关系到天然气储量的增长势头。克拉通盆地下层序古隆起控气理论和上层序非构造圈闭控气机理是克拉通大中型气田富集分布的基本规律,前陆盆地是我国富气盆地类型之一,其冲断带下盘大型造圈闭群、前缘斜坡岩性尖灭区带与浅层次生气藏、前缘隆起上的断块圈闭群等是该类盆地有利的天然气富集区带。依据充分的地质资料,结合我国天然气勘探实际,提