2001-2020年南海周边河流入海沉积物通量时空变化特征研究

在人类活动和快速气候变化的影响下,南海周边河流入海沉积物通量发生巨大变化。本文基于2001-2020年间南海周边河流数据及海表悬浮沉积物浓度数据,探究南海周边河流入海沉积物通量的时空变化特征。研究结果表明:2001-2020年南海周边河流入海沉积物通量超过345 Mt/a,人类活动导致珠江、红河、湄公河入海沉积物通量减少约300 Mt/a。南海周边河流入海沉积物通量还受台风和气候变化的影响:台风是影响南海周边河流入海沉积物通量的重要因素,尤其是台风期间台湾地区的高屏溪入海沉积物通量可达全年总量的89%。在东亚季风系统影响下,南海周边河流入海沉积物通量表现出雨季高、旱季低的变化特征,雨季期间入海沉积物通量占全年总量的80%以上,相应地,河流表层羽流在雨季具有浓度高和扩散范围大的典型特征。受厄尔尼诺-南方涛动的影响,南海周边河流流量和入海沉积物通量也存在不同周期变化,南海周边大型河流入海沉积物通量表现出2.5~3.0 a的变化周期,并与NI?O3.4指数存在相关性。本文利用20年的河流数据系统论证了台风、气候变化和大坝建设对21世纪以来南海周边河流入海沉积物通量的影响,在源汇过程研究及流域治理方面具有重要意义。

长江和黄河入海沉积物不同粒级中长石／石英比值及化学风化程度评价

长石／石英（V／Q）比值是评估碎屑沉积物化学风化强度的传统指标。在长江大通站和黄河利津站及相应河13区各取9个沉积物样品，将其〈125μm的部分按1夺间隔分离成7组不同的粒级，用X-ray衍射法半定量分析测定了全样和不同粒级沉积物中石英和长石的相对含量，计弹了长石／石英（F／Q）、钾长石／石英（Fk／Q）、斜长石／石英（Fp／Q）比值，据此评估了长江和黄河入海沉积物化学风化强度随粒级的变化。结果显示取自黄河样品的V／Q，Fk／Q和Fp／Q比值在总体上显著高于长江洋品，与长江流域的化学风化强度高于黄河的结论一致，可以作为流域沉积物化学风化强度替代指标。长江样品的F／Q，Fk／Q和Fp／Q比值随粒级变细持续变低，黄河样品则呈波动式下降。黄河样品的V／Q高出长江佯品的部分主要发生在〈32μm的细粒级，在粗粒级区间差别很小，当沉积物粒级下降到一定区间后V／Q差异出现快速增加，显示长江流域沉积物的风化程度高于黄河主要发生在较细粒级。上述比值在黄河洋品的2～4μm粒级中高出长江样品3～5倍，是凸显两河化学风化强度差别的敏感粒级，也可以作为两河物源示踪的指标。

长江和黄河入海沉积物的物源识别研究进展

长江和黄河每年输送近16亿t泥沙入海,是中国东部陆架海区最主要的陆源物质供应者。长江和黄河沉积物的物源识别一直是中国东部陆架海区沉积学热点问题之一,受到了广泛的关注。近年来,众多国内外学者运用矿物学、地球化学以及环境磁学等方法,对长江和黄河入海沉积物的物源识别做了深入研究,已经取得长足进展。在综合前人研究成果的基础上,系统地总结了长江、黄河物源识别指标,评述了各自的优劣,并对未来两条大河的物源识别工作提出了展望。

白令海表层沉积物中的放射虫与海洋环境

通过对白令海 1 2个表层沉积物中微体生物化石放射虫的分析 ,共鉴别放射虫 2 4 72枚 ,计36属、45种。表层沉积物中放射虫的分布特点为 :1 .浅水陆架 -陆坡上部区的粉砂、细砂沉积物中放射虫化石数量少且属种单调。2 .陆坡下部区的火山碎屑及浊流沉积物中放射虫化石亦不丰富。3.海盆区粘土沉积物中的放射虫化石丰度高且分异度高。本区陆架放射虫化石的优势种为Spongotrochus glacialis.影响放射虫分布的主要因素为海流、地形、水深、水温等。另外 ,该区沉积物的物源主要为陆源沉积物、生物源沉积物和火山源沉积物 ,它们主要来源于俄罗斯东部的勘察加半岛。

不同成因的海洋铁锰氧化物沉积物中稀土元素的地球化学特征

测试了具代表性的成岩型结核和水成型结壳的稀土元素 ,以研究稀土元素在这两种成因的海洋铁锰氧化物沉积物的特征及其与成因的关系。稀土元素特征表明稀土元素没有参与成岩型结核的成岩作用 ,即没有加入到1nm水锰矿中去 ,而是加入到无定形铁的氧化物、氢氧化物中去。同样 ,稀土元素也没有直接参与水成结壳的水成作用 ,即没有加入到锰、铁的氧化物、氢氧化物中去 ,而是与钙、磷相关 ,推测在很大程度上是先沉淀在钙、磷相中然后才加入到水成结壳中。

中太平洋海盆北中部的锰结核

1974—1978年日本“白令丸”对中太平洋海盆北中部海域进行了5个航次的地质学与地球物理学综合调查,概略地查明了该海域锰结核的分布特征以及地质学与地球物理学诸性质之间的关系。

Distribution and ecological evaluation of heavy metals in multi-medium of the Dongzhai Harbor

The distribution characteristics of heavy metals such as Cu, Zn, Pb, Cd, Hg. As in seawater, superficail sediments and several marine organisms of Dongzhai Harbor in Hainan were analyzed. Index methods of the single factor and geo-accumulation were used to assess the pollution degree of heavy metals. The results showed that the heavy metal levels in the seawater of Dongzhai Harbor accorded with the first category of the seawater except Pb, and were much lower than the fishery water quality standard; the concentration of the heavy metal in surface sediments did not exceed the national benchmark of the first-class of marine sediment quality basically, and the superficial sediments were essentially uncontaminated; the heavy metal content in wetland sediments was slightly higher than those in other typical mangrove wetland island of Hainan and marine sediments in Dongzhai Haibor, which indicated this area might has been affected by land-based pollution influence, and this should cause the attention of related departments; the heavy metal concentrations in marine organisms were up to the first category. All were not beyond the standard of non-environmental pollution aquatic products.

Distribution of Biogenic Silica Content in Surface Sediments from the Southern South China Sea and Its Environmental Dignificance

Biogenic silica content was determined in 25 surface sediment samples from the southern South China Sea to study its distribution and its modern oceanic environmental significance, which may provide further scientific evidence for paleoceanography explaination. This study showed that biogenic silica content in surface sediments and its water depth have evidently positive correlation, and the correlation coefficient was up to 0.782. Biogenic silica content was very low in continental shelf shallows and could not reflect the productivity of siliceous micropaleontology in surface waters, which may be affected by sedimentary types and terrigenous matter dilution. Distribution of biogenic silica content in surface sediments from deep water areas showed that it could not only reflect the paleoproductivity of siliceous micropaleontology in surface waters, but also indicate the strong or feeble upwelling. Thus, it was further confirmed that using biogenic silica content in sediments to trace upwelling and its change was effective and reliable. The analyzed result showed that radiolariia and poriferous specula have more contribution for biogenic opal, comparing with diatom in surface sediments from the northern studied area, probably owing to the diatom dissolved easily away and eaten by other organisms with little effort. In the upwelling areas, radiolarian, diatom and poriferous specula all approximately showed high abundance, which was consistent with high biogenic silica content.

Influence of Microstructure Change of Seafloor Sediments on the Sound Velocity in them in the Course of Stress-strain

Test tools and methods for synchronizing acoustic measurements in the course of stress-strain for seafloor sediment are elaborated and the test data of 45 sediment samples from the seafloor in the South China Sea are analysed. The result shows that the coarser the sediment grains are, the smaller the porosity is and the larger the unconfined compression strength is, the higher the sound velocity is. In the course of stress-strain, the sediment sound velocity varies obviously with the stress. Acoustic characteristics of sediment in different strain phases and the influence of sediment microstructure change on its sound velocity are discussed. This study will be of important significance for surveying wells of petroleum geology and evaluating the base stabilization of seafloor engineering.

Study on acid-volatile sulfide(AVS), simultaneously extracted metals(SEM) and its toxic effect on the organism in intertidal sediments of Donghai Island, Zhanjiang

The content and distribution of acid-volatile sulfide （AVS） and simultaneously extracted metals （SEM） （Cr Cu, Zn, Cd and Pb） were studied in surface sediments collected from the tidal fiat of Donghai Island, Zhanjiang. The results indicated that for most stations, the AVS concentration was higher in summer with the average of 0.449 μmol/g than that in winter with the average of 1.816 μmol/g. The AVS contents were higher in southern and northern areas and lower in western and eastern areas. The average content of ∑SEM was between 0.56 μmol/g and 4.60 μmol/g in summer and between 0.65μmol/g and 2.21 μmol/g in winter. The concentration change of single metal was Zn〉Cr〉Pb〉Cu〉Cd for most stations. The content percentage in ∑ SEM was below 1% for Cd and over 70% for Zn. SEMZn was the key pattern to control the distribution of T. SEM due to its high concentration percentage. Based on the assessment methods of （∑SEM/AVS） with （∑ SEM-AVS） and thresholds for metal toxicity to benthic organism, most values of （∑ SEM-AVS） in intertidal flats of Donghai Island were between 0 and 5. The most toxicity region was in Tongminghai area located in the west tidal zone of Donghai Island, and the most toxicity metal was zinc in Tongminghai area in summer. The land-based pollution and the environmental parameters such as sunlight, atmosphere temperature and hydrodynamic characteristics were the main affecting factors on the content level and distribution characteristics of AVS and SEM in intertidal sediments of Donghai Island.

An Overview of the Concept of Regional Sediment Management

In this article we described the concept of ＂regional sediment management＂ （RSM）, and identified opportunities for and impediments to implementing regional approaches to sediment management, and also summarized the background information and applications of RSM. Furthermore, we considered the needs of RSM studies and, suggested the framework for developing RSM strategies, and described the specific studies for the Xiamen region.

Geoacoustic inversion for sediments in the South China Sea based on a hybrid inversion scheme

We performed a long range acoustic propagation experiment in the South China Sea(SCS) in November 2004.The environment of the experiment was with an isothermal sound speed profile,where influence of water volume fluctuation was small,meaning that bottom parameters can be well estimated from acoustic signals.We inverted the acoustic parameters of sediment by using a hybrid inversion scheme that combines the matched field processing inversion with Hamilton sediment empirical relationship and transmission loss data.The numerical results show excellent agreement with the experiment data,indicating validity of the inverted parameters.

Chemical profile of the secondary metabolites produced by a deep-sea sediment-derived fungus Penicillium commune SD-118

Bioassay-guided fractionation of the crude extract from Penicillium commune SD-118, a fungus obtained from a deep-sea sediment sample, resulted in the isolation of a known antibacterial compound, xanthocillin X (1), and 14 other known compounds comprising three steroids (2-4), two ceramides (5 and 6), six aromatic compounds (7-12), and three alkaloids (13-15). Xanthocillin X (1) was isolated for the first time from a marine fungus. In the bioassay, xanthocillin X (1) displayed remarkable antimicrobial activity against Staphylococcus aureus and Escherichia coli, and significant cytotoxicity against MCF-7, HepG2, H460, Hela, Du145, and MDA-MB-231 cell lines. Meleagrin (15) exhibited cytotoxicity against HepG2, Hela, Du145, and MDA-MB-231 cell lines. This is the first report of the cytotoxicity of xanthocillin X (1).

A research on statistical retrieval algorithms and spectral characteristics of the total absorption coefficients in the Yellow Sea and the East China Sea

This paper suggests a group of statistical algorithms for calculating the total absorption coefficients based on in situ data of apparent optical property and inherent optical property collected with strict quality assurance according to NASA ocean bio-optic protocols in the Yellow Sea and the East China Sea in spring 2003. The band-ratios ofRrs412/Rrs555, Rrs49o/Rrs555 are used in the algorithms to derive the total absorption coefficients （at） at 412, 440, 488, 510, 532 and 555nm bands, respectively. The average relative errors between inversed and measured values are less than 25.8%, with the correlative coefficients （R2） being 0.75-0.85. Error sensitivity analysis shows that the maximum retrieval error is less than 24.0% at ＋5% error in Rrs＇s. So the statistical algorithms of this paper are practicable. In this paper, the relations between the total absorption coefficients at 412, 488, 510, 532, 555 nm and that of 440nm are also studied. The results show that the relations between the total absorption coefficients of 400-600 nm and that of 440 nm are correlated well and all of their correlative coefficients R2 are greater than 0.99. Furthermore, a regression analysis is also done for the slope of the linear relations and wavelengths, and the R2 is also 0.99. Thus it is possible to retrieve other bands＇ total absorption coefficients with only one band absorption value, which significantly reduce the number of unknown parameters in studying other ocean color related problems.

Geochemical analysis of marine sediments using fused glass disc by X-ray fluorescence spectrometry

A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard （for the trace elements）. The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% （n=12）.

MOLAR RATIOS OF C,N,P OF PARTICULATE MATTER AND THEIR VERTICAL FLUXES IN THE YELLOW SEA

The vertical fluxes and molar ratios of carbon, nitrogen and phosphorus of suspended particulate matter in the Yellow Sea were studied based on the analysis of suspended particulate matter, sediments and sinking particles obtained by use of moored sediment traps. The POC:PON ratios indicate that most of the particulate organic matter in the Yellow Sea water column comes from marine life rather than the continent. The vertical fluxes of SPM, POC, PON and POP in the Yellow Sea are much higher than those in other seas over the world, and present a typical pattern in shallow epicontinental seas. The estimated residence time of the bioactive elements showed that the speed of the biogeochemical process of materials in the Yellow Sea is much shorter than that in the open ocean as there was high primary productivity in this region.

Accumulation and exploration of gas hydrate in deep-sea sediments of northern South China Sea

The large deep-sea area from the southwestern Qiongdongnan Basin to the eastern Dongsha Islands,within the continental margin of northern South China Sea,is a frontier of natural gas hydrate exploration in China.Multiform of deep-sea sedimentations have been occurred since late Miocene,and sediment waves as a potential quality reservoir of natural gas hydrate is an most important style of them.Based on abundant available data of seismic,gravity sampling and drilling core,we analyzed the characteristics of seismic reflection and sedimentation of sediment waves and the occurrence of natural gas hydrate hosted in it,and discussed the control factors on natural gas hydrate accumulation.The former findings revealed the deep sea of the northern South China Sea have superior geological conditions on natural gas hydrate accumulation.Therefore,it will be of great significance in deep-sea natural gas hydrate exploration with the study on the relationship between deep-sea sedimentation and natural gas hydrate accumulation.

Enhancement of Laccase Activity by Marine-derived Deuteromycete Pestalotiopsis sp. J63 with Agricultural Residues and Inducers

Pestalotiopsis sp. J63, producing a high activity of laccase, is a new marine-derived fungus isolated from the oceanic sediment of the East China Sea. Since the marine environment is oligotrophic nutrient, marine derived fungi may use small amount of nutrients to grow and produce laccases. Agricultural residues that are mainly composed of lignin, cellulose and hemicellulose are difficult to be degraded and few microbes can take them as substrates, so they are considered as oligotrophic nutrient and have the potential to be used to produce value added products. In this study, the ability of Pestalotiopsis sp. J63 to use agricultural residues to produce laccases was tested in the submerged fermentation. The combination of 3 g·L 1maltose and 20 g·L 1rice straw was the best carbon sources and 8 g·L 1ammonium sulfate was the best nitrogen source under the condition without inducers. The effects of five inducers, the feeding time and concentration of inducer on laccase production were investigated.Adding 0.09 mmol·L 1phenol after 24 h of incubation led to high laccase activity(5089 U·L 1), while with 0.09mmol·L 1phenol in the medium and wheat bran as the nitrogen source, the laccase activity could reach 5791.7U·L 1. Native-PAGE results showed that two laccase isozymes were present in the cultures. One existed in both induced and non-induced culture filtrates, while the other was only found in the fermentation with the addition of phenol, guaiacol and veratryl alcohol.

Distribution and Accumulation Characteristics of Heavy Metals in Sediments in Southern Sea Area of Huludao City, China

The southern sea area of the Huludao City, Liaoning Province might be polluted by heavy metals because it is close to the Jinzhou Bay, one of the heaviest sea area polluted by heavy metals in China. The undisturbed modem sediment core can be used to analyze the accumulation and source of the pollutants using 137Cs and 21pbex. Thirty-five samples of surface sediment and two core sedi- ments were collected from the southern sea area of Huludao City. The concentrations of copper （Cu）, lead （Pb）, chrome （Cr）, zinc （Zn）, arsenic （As） and mercury （Hg） in the surface sediments as well as Cu, Pb, Zn, Cr, 137Cs and 2~~pbex in the core sediments were deter- mined to research the spatial distribution and accumulation characteristics, and to analyze the sources and the potential risks of heavy metals. The results show that the pollution levels of Zn and Hg are serious, and 26 stations are at moderate or heavy ecological risks. The concentrations of the heavy metals increase from east to west, as well as from open sea to offshore marine area. The concentrations of heavy metals are not high in the sediments adjacent to the Jinzhou Bay, and the influence caused by the seawater exchange with the Jinzhou Bay is little. The concentrations of the heavy metals in the core sediments show low-high-low characteristic, and it coincides with the pollution history of Huludao City. The atmospheric deposition of heavy metals from the Huludao Zinc Plant is likely to be the main source of pollution without direct discharge of wastewater. The high concentrations of heavy metals appear on the upper sediment of 20 cm. The shallow sediment with high heavy metal contents might be exposed to surface when it was disturbed by the ocean engineering and big storm surge, then cause risk to the safety of aouaculture and human honlthy.