海水现场水色色度及渤海水域水色色度分析

叙述了目前海水现场水色测量的弊端 ,指出数字化海洋水色的潜在应用价值 ;根据色度学及色度学的三原色基本理论 ,确定海洋现场水色的色度要素 ,使海洋现场水色标号统一为物理学中严格的颜色物理量。结合 1 996年渤海水域光谱反射测量 ,对渤海水域 4个典型站位的反射光谱做了水色色度分析 ,并进行了 2种测量方法的比较     

利用卫星遥感技术监测赤潮的研究

赤潮灾害的频繁发生，给海洋生态环境和海洋渔业经济造成了严重危害。卫星遥感技术的不断完善，为快速、有效地动态监测赤潮灾害提供了可能，通过卫星图片的校正、合成、分析、解释、判断分析，可以迅速连续地掌握赤潮的发生状况，对于研究防控和治理赤潮灾害有着十分重要的意义，本文就如何利用卫星遥感技术监测赤潮进行了探讨。     

北太平洋亚热带环流区表层水中226Ra和228Ra的分布与变化

对1999年9～10月采自北太平洋亚热带环流区的19份表层海水样品的Ra同位素分析表明。研究海域表层水中的^226Ra、^228Ra放射性比度分别介于0．67～0．92、0．08～0．30Bq／m^3之间，平均值分别为0．74、0．11Bq/m^3．^226Ra/^228Ra)A．R．活度比的变化范围为0．11～0．44，平均值为0．19．上述数值明显低于近岸海域水体的相应值，表现为典型的开阔大洋水的特征．从空间分布的特征看，研究海域Ra同位素含量与^226Ra/^228Ra)A.R.值均呈均匀分布态势．将本研究结果与历史数据进行对比后发现，本研究获得的^226Ra、^228Ra放射性比度比20世纪60～80年代得到的数据来得低，可能与水体层化作用加强导致的Ra补充量的减少以及生物生产力升高导致的Ra迁出量的增加有关．北太平洋亚热带环流区表层水中Ra同位素的时间变化与文献报道的该海域叶绿素a、硅酸盐、磷酸盐含量与初级生产力的历史变化趋势相吻合．     

高分辨率遥感技术在厦门海湾生态环境调查中的应用

对于局部区域研究，高分辨率卫星遥感及其影像的智能化处理技术是获取信息的新手段．本文以IKONOS遥感影像在厦门海湾的应用为例，探讨高分辨率遥感卫星影像应用于海湾生态环境调查与分析的应用技术．通过分析高分辨率影像地物特征，提出高分辨率遥感影像的重要处理技术：采用不同缩放尺度进行分类和利用空间特征及纹理结构进行专题信息提取。     

遥感与GIS支持下的海洋渔业空间分布研究——以东海为例

基于海洋渔业多年来生产实践所表明的海洋渔场与海洋水文要素密切相关性,将研究区的遥感融合信息与生产数据进行GIS空间配准,同时建立了诸多要素数据的空间聚类模式,利用该模式提取了水文信息和中心渔场信息相关联的空间分布规律的隐伏信息,由此阐述了实现海洋渔业现代化,应用空间遥感融合信息和GIS支持下指导海洋渔业生产的渔情预报有着重要意义.     

Non-local impact of large-scale engineering in harbors and gulfs on the environment

A system of numerical tools to predict the non-local long-term impact of large-scale constructions on the environment is described. The predictions have to be results of successive examination of free water oscillations, turbulent boundary layers on the sea bottom, and turbulent pulsation effects on sediment transport. Numerical results related to free water oscillations in diverse gulfs are shown, and non-local effects of the dam construction are found for an example of the Baltic Sea. Feasibility of suggested tools for turbulent flow is manifested.     

Variation in Water Masses on Shelf of Northern Bering Sea in September 2016-2018

Abstract

Based on hydrological data obtained during the 7th to 9th Chinese National Arctic Research Expeditions in the summers of 2016–2018, the main water structure on the shelf of the northern Bering Sea and the volume and heat fluxes of the Bering Strait throughflow were analyzed. Distinct variability was identified in the three Pacific water masses feeding the strait - Anadyr Water (AW), Bering Shelf Water (BSW) and Alaskan coastal water (ACW). Overall, the temperature and salinity of the entire section increased each year, with 2018 showing significant anomalies, i.e., a temperature anomaly of up to 1?°C and a maximum salinity anomaly of 2. From 2016 to 2018, the extent of the ACW gradually narrowed in the eastern part of this section, while the AW expanded eastward each year. The net volume transport through each of the three sections increased poleward from 1.65?Sv to 2.76?Sv, with the AW increasing from 0?Sv to 1.03?Sv, the BSW varying between 0.52–1.65?Sv, and the ACW gradually decreasing from 1.04?Sv to disappearing completely. The net heat fluxes were also poleward, varying between 25.77 TW and 61.50 TW, and showing a significant increase. Significant variations in magnitude and extent were observed in each water mass of the Bering Strait throughflow, which could produce widespread effects in the Arctic Ocean and the global ocean beyond.     

Mercury speciation in surface and deep waters of the Mediterranean Sea

Mercury speciation and its distribution in surface and deep waters of the Mediterranean Sea were studied during two oceanographic cruises on board the Italian research vessel URANIA in summer 2003 and spring 2004 as part of the Med Oceaneor and MERCYMS projects. The study included deep water profiles of dissolved gaseous Hg (DGM), reactive Hg (RHg), total Hg (THg), monomethyl Hg (MeHg) and dimethyl Hg (DMeHg) in open ocean waters. Average concentrations of measured Hg species were characterized by seasonal and spatial variations. Overall average THg concentrations ranged between 0.41 and 2.65 pM (1.32 ± 0.48 pM) and were comparable to those obtained in previous studies of the Mediterranean Sea. A significant fraction of Hg was present as “reactive” Hg (average 0.33 ± 0.32 pM). Dissolved gaseous Hg (DGM), which consists mainly of Hg⁰, represents a considerable proportion of THg (average 20%, 0.23 ± 0.11 pM). The portion of DGM typically increased towards the bottom, especially in areas with strong tectonic activity (Alboran Sea, Strait of Sicily, Tyrrhenian Sea), indicating its geotectonic origin. No dimethyl Hg was found in surface waters down to the depth of 40 m. Below this depth, its average concentration was 2.67 ± 2.9 fM. Dissolved fractions of total Hg and MeHg were measured in filtered water samples and were 0.68 ± 0.43 pM and 0.29 ± 0.17 pM for THg and MeHg respectively. The fraction of Hg as MeHg was in average 43%, which is relatively high compared to other ocean environments. The concentrations reported in this study are among the lowest found in marine environments and the quality of analytical methods are of key importance. Speciation of Hg in sea water is of crucial importance as THg concentrations alone do not give adequate data for understanding Hg sources and cycling in marine environments. For example, photoinduced transformations are important for the presence of reactive and elemental mercury in the surface layers, biologically mediated reactions are important for the production/degradation of MeHg and DGM in the photic zones of the water column, and the data for DGM in deep sea indicate the natural sources of Hg in geotectonicaly active areas of the Mediterranean Sea.     

Cycladophora davisiana (Radiolaria) in the Okhotsk Sea: A key for reconstructing glacial ocean conditions

Cycladophora davisiana, a radiolarian species dwelling at mesopelagic depths, is known as a representative glacial fauna due to its unique distribution during glacial periods. In the present ocean, abundant production of C. davisiana is only observed in the Okhotsk Sea, indicating an adaptation of C. davisiana for seasonal sea-ice covered conditions. We found pronounced abundant production of C. davisiana during the early to middle Holocene in the Okhotsk Sea, suggesting more favorable conditions for C. davisiana than the present Okhotsk Sea. In order to clarify the reason, oceanographic conditions during the Holocene were reconstructed based on biomarkers, lithogenic grains including ice-rafted debris (IRD), biogenic opal, and total organic carbon (TOC) in two sediment cores from the Okhotsk Sea. These indicators suggest that the pronounced C. davisiana production may be attributed to: 1) a supply to mesopelagic depths under intensified stratification of fine organic particles derived from coccolithophorids, bacteria, and detrital materials; and 2) cold, well-ventilated intermediate water formation.     

Determination of phospholipid fatty acid structures and stable carbon isotope compositions of deep-sea sediments of the Northwest Pacific, ODP site 1179

Sediment samples ranging from 0.05 to 278 m below sea floor (mbsf) at a Northwest Pacific deep-water (5564 mbsl) site (ODP Leg 191, Site 1179) were analyzed for phospholipid fatty acids (PLFAs). Total PLFA concentrations decreased by a factor of three over the first meter of sediment and then decreased at a slower rate to approximately 30 mbsf. The sharp decrease over the first meter corresponds to the depth of nitrate and Mn(IV) reduction as indicated by pore water chemistry. PLFA-based cell numbers at site 1179 had a similar depth profile as that for Acridine orange direct cell counts previously made on ODP site 1149 sediments which have a similar water depth and lithology. The mole percentage of straight chain saturated PLFAs increases with depth, with a large shift between the 0.95 and 3.95 mbsf samples. PLFA stable carbon isotope ratios were determined for sediments from 0.05 to 4.53 mbsf and showed a general trend toward more depleted δ¹³C values with depth. Both of these observations may indicate a shift in the bacterial community with depth across the different redox zones inferred from pore water chemistry data. The PLFA 10me16:0, which has been attributed to the bacterial genera Desulfobacter in many marine sediments, showed the greatest isotopic depletion, decreasing from − 20 to − 35‰ over the first meter of sediment. Pore water chemistry suggested that sulfate reduction was absent or minimal over this same sediment interval. However, 10me16:0 has been shown to be produced by recently discovered anaerobic ammonium oxidizing (anammox) bacteria which are known chemoautotrophs. The increasing depletion in δ¹³C of 10me16:0 with the unusually lower concentration of ammonium and linear decrease of nitrate concentration is consistent with a scenario of anammox bacteria mediating the oxidation of ammonium via nitrite, an intermediate of nitrate reduction.