九龙江口水体中1995年磷的转移

1995年3个航次的调查研究结果表明,九龙江口水体总磷含量受悬浮物含量控制,在S＜5的低盐度区,悬浮泥沙和磷产生明显的絮凝沉降,在S＞5时,它们的迁移接近于理想混合。溶解磷的河口转移与其在河流端的浓度密切相关。当河端浓度低时,磷略呈溶出现象;而河端浓度高时则接近于理想混合过程。估算得出九龙江河流总磷的平均入海通量为2．9×103t／a,其中溶解磷和颗粒磷各占一半左右。     

胶州湾东部磷的形态及分布

报道了胶州湾东部自１９９０年１１月－１９９１年８月４个季节各种磷的含量及分布情况；总磷年平均含量为３．２６μｍｏｌ／ｄｍ＾３；颗粒磷是主要形态，占总磷的５２％，溶解态无机磷占２４％；秋季各种磷含量最高，是矿化再生的主要季节，春，冬浮游植物大量繁殖，吸收磷酸盐，浓度下降。夏季磷受物理混合过程所控制。     

九龙江口水体中1995年有机物的转移

1995年3个航次调查研究结果表明,九龙江口水体总有机物的含量受悬浮物含量控制。在S＜5的低盐度区,悬浮泥沙和有机物产生明显的絮凝沉降;在S＞5的广阔海域,它们的迁移接近于理想混合。估算得出九龙江河流的入海通量约：悬浮泥沙为9．8×105t／a;总COD为3．2×104t／a,其中溶解态COD为2.1×104t／a,约占2／3,为水体有机物的主要形态,如换算为溶解有机碳,则DOC的平均通量为3．2×104t／a。     

黄河下游营养盐浓度、入海通量月变化及“人造洪峰”的影响

于2009年至2011年在黄河下游采集溶解及颗粒态营养盐样品,分析了黄河下游各形态营养盐的浓度变化及营养盐入海通量,结果表明各形态氮的浓度多呈丰水期低、枯水期高,溶解无机氮是溶解态氮的主要存在形式;受黄河高悬浮颗粒物含量的影响,磷以颗粒态占绝对优势,而溶解态磷以溶解无机磷为主要存在形态;生物硅的含量平均约占硅酸盐与生物硅之和的20％,硅的浓度丰水期高于枯水期.颗粒态磷与生物硅的含量与悬浮颗粒物含量呈正相关.营养盐的组成具有高氮磷比、高硅磷比、低硅氮比的特点.近年来黄河下游溶解无机氮浓度显著升高而溶解无机磷变化不大,硅酸盐的浓度有所下降.黄河下游水沙通量、营养盐入海通量有明显的季节变化,丰水期占全年总入海通量的42％～84％.调水调沙期间,各营养盐的浓度和组成均有明显变化,氮的浓度、DIN/PO4-P下降,磷与硅的浓度、SiO3-Si/DIN、SiO3-Si/PO4-P升高,颗粒态营养盐的比例明显增加.短期内大量水沙及营养盐入海通量对黄河口及渤海生态系统产生重要影响.     

黄河下游营养盐浓度季节变化及其入海通量研究

2001年3月～2002年2月期间在黄河下游采集溶解及颗粒态营养盐样品,分析了黄河径流中各形态的营养盐的浓度及其月动态,估算此时段内黄河的营养盐入海通量。研究发现,溶解无机氮是溶解总氮的主要存在形式,硝酸盐是黄河中氮的最主要存在形态,其季节变化与水量变化趋势相反,年平均含量为(260.6±84.0)μmol/L,显著高于世界其它河流,为世界背景值(7.14μmol/L)的20多倍;黄河中磷主要以颗粒态存在,颗粒态磷含量变化规律与SPM的分布一致,其年平均含量为(16.2±22.9)μmol/L,磷酸盐含量较低,年平均含量为(0.42±0.20)μmol/L,与世界河流的平均水平相当。硅酸盐年平均含量为(122.0±18.2)μmol/L。每年约有17 200 t的总氮和1 600 t的总磷输入渤海,氮通量表现出在春季3月较高;磷通量在9月出现最高值,春季3,4月也较高;硅酸盐通量在3月出现最高值。     

九龙江口生物可利用磷的行为与入海通量

于1995年3、5月在九龙江口进行两个航次的现场调查,研究不同形态磷的河口行为,并估算生物可利用磷的入海通量。结果表明,在S＜20区域内,溶解活性磷（DRP）的行为受控于“缓冲机制”,其含量在8～10μg／dm3水平上下波动。颗粒磷中MgCl2。可提取磷（MgCl2-P）含量随盐度增大而增大,并与叶绿素a以及悬浮物中Fe、Mn、Al含量呈正相关关系。NaOH／NaCl可提取磷（NaOH／NaCl－P）随盐度增大按指数关系下降,其含量与悬浮物中Fe、Mn、Al含量呈正相关关系。HCl可提取磷（HCl－P）在河口区的行为表现为保守混合。九龙江口生物可利用磷入海通量约517t／a,其中潜在生物可利用磷（PBAP）的贡献为溶解活性磷（DRP）的3倍。     

九龙江口海域中磷的化学形态分布

根据１９８７年３月至１９８８年１２月笔者在九龙江口，厦门西海域的调查研究资料，着重讨论颗粒态磷，溶解态无机磷，溶解态有机磷，总磷等各种形态磷的含量分布，季节变化，及其与叶绿素，总悬浮物量等其他要素的关系。     

九龙江口、厦门西海域磷的生物地球化学研究──Ⅲ.生物活动参与下的磷形态转化及磷循环估算

１９８７年３月～１９８８年１２月笔者于九龙江口、厦门西海域的调查研究结果表明，厦门西海域特殊的地理、水文环境、沉积物的高磷量、磷形态的快速转化是西海域初级生产力［５５５ｇ／（ｍ２·ａ）］比九龙江口区［１５９ｇ／（ｍ２·ａ）］高得多的主要原因。颗粒态磷（ＰＰ）、溶解态无机磷（ＤＩＰ）、溶解态有机磷（ＤＯＰ）等以生物为媒介发生了某种程度的形态转化。本文估算了九龙江水总磷（ＴＰ）的入海通量为７８７ｔ／ａ，其中ＤＩＰ为６９．２ｔ／ａ，ＤＯＰ为１７０ｔ／ａ，ＰＰ为５４７ｔ／ａ；九龙江口和厦门西海域沉积物磷的年释放量估计为１６ｔ和１３ｔ．接初级生产力估算全调查海域消耗磷约为９８１ｔ／ａ，而生物活动参与下磷的再生和转化起重要的作用。     

九龙江口海域中磷的化学形态分布

根据１９８７年３月至１９８８年１２月笔者在九龙江口、厦门西海域的调查研究资料，着重讨论颗粒态磷（ＰＰ）、溶解态无机磷（ＤＩＰ）、溶解态有机磷（ＤＯＰ）、总磷（ＴＰ）等各种形态磷的含量分布、季节变化，及其与叶绿素（Ｃｈｌ．ａ）、总悬浮物量（ＴＳＭ）等其他要素的关系。     

九龙江口、厦门西海域磷的生物地球化学研究──Ⅲ.生物活动参与下的磷形态转化及磷循环估算

１９８７年３月～１９８８年１２月笔者于九龙江口、厦门西海域的调查研究结果表明，厦门西海域特殊的地理、水文环境、沉积物的高磷量、磷形态的快速转化是西海域初级生产力［５５５ｇ／（ｍ＾２·ａ）］比九龙江口区［１５９ｇ／（ｍ＾２·ａ）］高得多的主要原因。颗粒态磷（ＰＰ）、溶解态无机磷（ＤＩＰ）、溶解态有机磷（ＤＯＰ）等以生物为媒介发生了某种程度的形态转化，本文估算了九龙江水总磷（ＴＰ）的入海通量为７８７ｔ     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.