黑潮化学物质输入东海的途径与通量

在对黑潮水文特征分析的基础上,探讨了黑潮对中国近海化学物质输入途径,归纳总结了黑潮对东海生源要素、痕量元素、同位素及其他化学物质的输入特征,提出了黑潮对中国近海化学物质输入研究应着重关注的问题。主要的结论包括:吕宋海峡、中国台湾东北部及日本九州西南海域是黑潮向中国近海输送化学物质的3个关键区域;黑潮表层水向东海陆架的扩展、次表层水和中层水的涌升以及黑潮季节性流轴摆动是黑潮向东海输送化学物质的基本途径。黑潮主体生源要素的浓度随深度的增加而增大。黑潮对东海生源要素的影响夏季最弱、春季次之、秋冬季最强,其对东海生源要素的输入通量要远高于河流、大气等其他输入源,并且各水层中以中层水的生源要素输入通量为最大。痕量元素在黑潮主体的分布、对东海的输入通量等方面均表现出了与生源要素的差异,各痕量元素的分布及输入通量随痕量元素的不同而不尽相同,其中次表层水的涌升在对邻近海域痕量元素分布的影响中起到了重要作用。同位素可指示黑潮对东海陆架的入侵程度及变化规律,并与营养盐等有一定的相关性。黑潮是东海微量温室气体N2O,CH4等其他化学物质的重要输入源,进而对东海生态环境产生影响。进一步研究应着重从系统性外海观测、痕量元素及同位素等化学物质调查、黑潮对中国近海输入化学物质的控制过程等方面深入开展。     

翡翠的白色次生变化产物初步研究

翡翠的白色次生物通常与褐色次生物共存,说明两者形成于相同的表生环境,即氧化环境。白色次生物既可以白沙皮的形式出现,也可以白色絮状物或白斑的形式存在于翡翠的裂隙及其附近颗粒之间。白色次生物在翡翠中以细小粘土矿物等的集合体形式分布于硬玉颗粒的边缘和裂隙中,以交代结构为主,充填结构为辅。结合红外光谱分析和电子探针测试可知,翡翠中的白色次生变化产物以高岭石或高岭石质为主,另外含有不常见的副钡长石和氟硅钙钠石,说明白色次生物的矿物组成较为复杂。     

Dolomite formation within microbial mats in the coastal sabkha of Abu Dhabi (United Arab Emirates)

Microbial mediation is the only demonstrated mechanism to precipitate dolomite under Earth surface conditions. A link between microbial activity and dolomite formation in the sabkha of Abu Dhabi has, until now, not been evaluated, even though this environment is cited frequently as the type analogue for many ancient evaporitic sequences. Such an evaluation is the purpose of this study, which is based on a geochemical and petrographic investigation of three sites located on the coastal sabkha of Abu Dhabi, along a transect from the intertidal to the supratidal zone. This investigation revealed a close association between microbial mats and dolomite, suggesting that microbes are involved in the mineralization process. Observations using scanning electron microscopy equipped with a cryotransfer system indicate that authigenic dolomite precipitates within the exopolymeric substances constituting the microbial mats. In current models, microbial dolomite precipitation is linked to an active microbial activity that sustains high pH and alkalinity and decreased sulphate concentrations in pore waters. Such models can be applied to the sabkha environment to explain dolomite formation within microbial mats present at the surface of the intertidal zone. By contrast, these models cannot be applied to the supratidal zone, where abundant dolomite is present within buried mats that no longer show signs of intensive microbial activity. As no abiotic mechanism is known to form dolomite at Earth surface conditions, two different hypotheses can reconcile this result. In a first scenario, all of the dolomite present in the supratidal zone formed in the past, when the mats were active at the surface. In a second scenario, dolomite formation continues within the buried and inactive mats. In order to explain dolomite formation in the absence of active microbial metabolisms, a revised microbial model is proposed in which the mineral‐template properties of exopolymeric substances play a crucial role.     

Evaluation of Greek low-rank coals as potential raw material for the production of soil amendments and organic fertilizers

This study evaluates Greek peat and coal samples for applications in the agricultural/horticultural sector and assesses the suitability of a certain peat/coal either as soil conditioner or as raw material for manufacturing organic fertilizers.Twenty-six samples of different rank ranging from peat to subbituminous coal obtained from several Greek peat/coal deposits, were studied. The laboratory tests included: a) pH and electrical conductivity (EC) determinations, as well as proximate, ultimate and maceral analyses, in order to characterize the samples, b) major and trace element analyses of both the total and the easily exchangeable fractions (EEF), in order to assess the phytotoxicity effect, c) cation exchange capacity (CEC) determination in mixtures of the samples (5 wt.%) with a certain soil (95 wt.%), in order to evaluate the peat/coal impact, and d) the determination of the contents of humic substances (HS), as well as of carboxylic and phenolic groups.The majority of the samples reveal moderate to high ash yields (16–80 wt.%), a slightly acidic to neutral character and electrical conductivity ranging from 100–2500 μS/cm. Concerning the environmental impact of the sensitive trace elements, which might be leached, As, Mn, Ni and Sr show relatively strong mobilization in some samples, although severe impacts are not expected. The soil's CEC is generally improved, although it remains at moderate levels. The most interesting aspect is the humic acids content, which ranges between 9.6 and 52.2 wt.% on a dry basis, exceeding 25 wt.% for most of the samples. The obtained results enable an initial correlation among the different parameters and a rating of the samples according to their suitability for soil-amelioration agents.     

海洋褐藻叉开网翼藻中的单萜成分研究

为了研究中国沿海海藻中的活性化学成分, 利用正相硅胶柱色谱、Sephadex LH-20 柱色谱、反相HPLC 及重结晶等手段, 从采自青岛的褐藻叉开网翼藻(Dictyopteris divaricata Okam.)中首次分离得到了6 个单萜类化合物, 经红外波谱(IR), 质谱(MS)及核磁共振波谱(¹H NMR、¹³C NMR)等现代波谱技术鉴定为loliolide (1), isololiolide (2), 3β-hydroxy-5α,6α-epoxy-7-megastigmen-9-one (3), dehydrovomifoliol(4), (3R)-4-[(2R,4S)-2-hydroxy-2,6,6-trimethylcyclohexylidene]-3-buten-2-oneiol (5), (3R)-4-[(2R,4S)-4-acetoxy-2-hydroxy-2,6,6-trimethylcyclohexylidene]-3-buten-2-one (6)。并通过MTT 法对所得化合物进行细胞毒活性筛选, 通过比色法进行乙酰胆碱酯酶抑制活性筛选。     

近年来海洋生物活性多肽的研究概况与展望

海洋是地球上资源最丰富的领域，海洋生物是新型肽类生物活性物质的重要来源。科学研究证明，许多海洋多肽具有抗肿瘤、抗艾滋病、抗真菌、抗病毒、防治心脑血管疾病及免疫调节等药理活性。本文简要介绍了近5a来国内外对海洋生物活性肽的研究概况，并进行了概括性展望。     

Antifouling activities of marine bacteria associated with sponge (Sigmadocia sp.)

The present study aimed at assessing the antifouling activity of bacteria associated with marine sponges. A total of eight bacterial strains were isolated from the surface of sponge Sigmadocia sp., of them, SS02, SS05 and SS06 showed inhibitory activity against biofilm-forming bacteria. The extracts of these 3 strains considerably affected the extracellular polymeric substance producing ability and adhesion of biofilm-forming bacterial strains. In addition to disc diffusion assay, microalgal settlement assay was carried out with the extracts mixed with polyurethane wood polish and coated onto stainless steel coupons. The extract of strain SS05 showed strong microalgal settlement inhibitory activity. Strain SS05 was identified as Bacillus cereus based on its 16S rRNA gene. Metabolites of the bacterial strains associated with marine invertebrates promise to be developed into environment-friendly antifouling agents.     

铁细菌胞外多聚物对铁矿物的调控形成及其环境意义

环境介质溶液中铁的水解作用和稳定化作用主要受铁细菌及其代谢有机物质的影响。铁细菌普遍存在于自然环境中,可利用低价铁源为自身生长所需能量。铁细菌胞外有机物的主要组分如多糖和蛋白质等可与铁结合,并通过氧化或沉淀作用使铁稳定、沉积而形成铁矿物;此外铁细菌胞外多聚物可催化铁的氧化或促进铁的聚集。这些生物成因铁矿物因具有良好的表面吸附与氧化还原等化学活性,及有效固定环境中的重金属、放射性核素和催化降解有机污染物的良好环境属性,在环境生物矿物材料和环境治理研究领域被日益重视。故本文基于铁细菌及其胞外多聚物对铁矿物矿化形成的重要调控作用,介绍了环境中存在的铁细菌及其生物矿化特征,重点阐述了铁细菌胞外多聚物(组分、结构及特性)及其在铁矿物矿化过程中的作用,同时对铁细菌胞外多聚物及生物成因铁矿物的环境意义进行了概述。