An optical model for the remote sensing of coloured dissolved organic matter in coastal/ocean waters

An optical model is developed for the remote sensing of coloured dissolved organic matter (CDOM) in a wide range of waters within coastal and open ocean environments. The absorption of CDOM (denoted as a_g) is generally considered as an exponential form model, which has two important parameters – the slope S and absorption of CDOM at a reference wavelength a_g(λ₀). The empirical relationships for deriving these two parameters are established using in-situ bio-optical datasets. These relationships use the spectral remote sensing reflectance (R_rs) ratio at two wavelengths R_rs(670)/R_rs(490), which avoids the known atmospheric correction problems and is sensitive to CDOM absorption and chlorophyll in coastal/ocean waters. This ratio has tight relationships with a_g(412) and a_g(443) yielding correlation coefficients between 0.77 and 0.78. The new model, with the above parameterization applied to independent datasets (NOMAD SeaWiFS match-ups and Carder datasets), shows good retrievals of the a_g(λ) with regression slopes close to unity, little bias and low mean relative and root mean square errors. These statistical estimates improve significantly over other inversion models (e.g., Linear Matrix-LM and Garver-Siegel-Maritorena-GSM semi-analytical models) when applied to the same datasets. These results demonstrate a good performance of the proposed model in both coastal and open ocean waters, which has the potential to improve our knowledge of the biogeochemical cycles and processes in these domains.     

Delamination of smectite in river-borne suspensions at the fluvial/marine interface – An experimental study

Fine fractions (<2 μm) from smectite-rich flood-plain sediments from the Elbe and Weser rivers in Germany were treated in the laboratory with synthetic sea salt solutions at different concentrations and for different periods of time to document sheet delamination of smectite particles at the fluvial/marine interface and thus simulate changes in clay minerals at the mouth of a river. The project consisted of two steps: (1) Pilot tests were made in 0.5% salt solutions (brackish environment) showing a nearly 2-min delay of the clearing of the clayey suspensions, when the suspension was redispersed 15 and 30 min later after the first measurement. This was due to an obviously increased number of fine laminae from disintegrated smectite particles. (2) X-ray diffraction studies (XRD) of the clayey material from suspensions in 0.0, 0.5, 1.0, and 3.0% salt solutions after standing 10 min, and one and three weeks were made to document alteration reactions of smectite. An aliquot was pipetted periodically from each series, and oriented clay-mineral specimens were analyzed by XRD in air-dried, glycol- and glycerin-solvated states. The peak intensities in the XRD patterns of the clay minerals smectite, random-ordered mixed-layer illite/smectite (I–S), kaolinite, chlorite, and illite did not change in the salt-free series during the experiments. In contrast the peak intensities of smectite and I–S mineral in the air-dried and glycerin-solvated states after suspension in saline solutions decreased significantly. The d-values of the smectitic materials in the air-dried state also decreased after contact with the saline solutions, and in the glycerin-solvated state the full-width-at-half-maximum (FWHM) of the 001 smectite reflection increased by about 20%, indicating a reduction in grain size.     

长江口及邻近海域夏季表层沉积物中重金属等的分布、来源与沉积物环境质量

通过现场调查研究报道了长江口及邻近海域表层沉积物中重金属、有机碳、石油类、硫化物以及氮磷的分布、来源以及沉积物环境质量.结果显示,长江口及邻近海域表层沉积物中重金属、有机碳、石油类、硫化物以及氮磷的分布很不均匀,除硫化物外,重金属、有机碳、石油类以及氮磷基本呈现长江口和杭州湾东北近岸的上海外海出现高值,其他区域浓度较低...     

Barnacles as biomonitors of metal contamination in coastal waters

The use of barnacles as biomonitors of metal contamination in coastal waters worldwide is reviewed as a critique compilation of the reported studies and presents resume-tables of available data for future reference. The barnacle body reflects both short and long-term metal level environmental variations and the metal bioaccumulation occurs mainly in their granules (relatively inactive pools). The barnacle body is considered as good biomonitoring material and different barnacle species could bioaccumulate metal concentration ranges of 40–153,000 μg/g of Zn, 20–22,230 μg/g de Fe, 1.5–21,800 μg/g of Cu, 5.9–4742 μg/g of Mn, 0.1–1000 μg/g of Pb, 0.7–330 μg/g of Cd, 0.4–99 μg/g of Ni and 0.2–49 μg/g of Cr. However, as the plates (‘shells’) of barnacle exoskeletons can be affected by metal levels in coastal waters, mainly in their composition and morphology, they are not considered good biomonitoring material. Despite this, the use of a specific barnacle species or group of species in a specific region must firstly be carefully validated and the interpretation of the contaminant bioaccumulation levels should involve specific environmental variations of the region, physiological parameters of the barnacle species and the relationship between the potential toxicity of the contaminant for the environment and their significance for the barnacle species. Barnacles, particularly a widespread cosmopolitan species such as Amphibalanus amphitrite, have a great potential as biomonitors of anthropogenic contamination in coastal waters and have been used worldwide, including Europe (United Kingdom, Turkey, Poland, Croatia, Spain and Portugal), Asia (India and China), Oceania (Australia), North America (Florida, Massachusetts and Mexico) and South America (Brazil). The use of barnacle species as biomonitors of metal contamination in coastal waters is considered an important and valuable tool to evaluate and predict the ecological quality of an ecosystem.     

What role do beds of submerged macrophytes play in structuring estuarine fish assemblages? Lessons from a warm-temperate South African estuary

Habitat variability is one of the factors influencing species richness within estuarine systems, and a loss of habitat can result in a restructuring of the estuarine ichthyofaunal assemblage, particularly if these conditions persist over long time periods. The potential effects of the loss of extensive submerged macrophyte beds (Ruppia cirrhosa and Potamogeton pectinatus) on an estuarine fish assemblage were investigated through an analysis of a long-term seine net catch dataset from the temporarily open/closed East Kleinemonde Estuary, South Africa. Catch data for a 12-year period, encompassing six years of macrophyte presence and six years of macrophyte senescence, indicated that the loss of this habitat did not influence species richness but changes in the relative abundance of certain species were evident. A shift in dominance from vegetation-associated species to those associated with sandy environments (e.g. members of the family Mugilidae) was observed. However, species wholly dependent on macrophytes such as the critically endangered estuarine pipefish Syngnathus watermeyeri were only recorded during years when macrophyte beds were present, while vegetation-associated species such as the sparid Rhabdosargus holubi persisted at lower levels of relative abundance. The reduced abundance of all vegetation-associated fish species during years of macrophyte senescence was probably reflective of declining food resources resulting from the loss of macrophyte beds and/or increased vulnerability to predation. Submerged beds of aquatic plants are therefore important habitats within temporarily open/closed estuaries, South Africa’s dominant estuary type.     

厦门沿岸海域杂色鲍中产琼胶酶菌株的筛选及其酶学性质的研究

琼胶酶在食品工业中的多糖降解中有着重要的作用,其经济价值日益凸显,从海洋生物中筛选琼胶酶菌株是获得琼胶酶的一种重要途径.从厦门沿岸海域养殖杂色鲍鱼体内分离得到5株产高效琼胶酶的菌株,其中最高的酶活力达到133.5 U/dm3.经16S rRNA序列分析表明这5株菌株分别属于弧菌属（Vibrio）和假交替单胞菌属（Pseudoa lteromonas）.采用DNS法对这些菌株所产的琼胶酶进行酶学性质研究,结果显示这些酶的最适作用温度均为50℃,最适作用pH值为7.0;Na＋可使A017菌株所产的琼胶酶酶活力提高5倍,Fe2＋对A007、A008、A010、A021菌株所产的琼胶酶酶活力有明显的抑制作用.     

海南岛近岸海域鱼类群落结构研究

根据2006—2007年在海南岛近岸区进行了4个航次的底拖网调查资料,分析了海南岛近岸区的鱼类种类组成和群落特征。结果显示,海南岛近岸区鱼类丰富,共捕获283种,隶属于21目100科170属,暖水性种占83.4%,暖温性种类16.6%;与大西洋、印度洋和太平洋的共有种分别为12种、173种、283种,与黄渤海、东海、日本、菲律宾和印度尼西亚的共种分别为75种、217种、186种、131种和151种;相对资源量指数与相对资源密度指数的季节变化趋势相一致,最高值在夏季,最低值在冬季;优势种(IRI≥500)为发光鲷(Acropoma japonicum)、斑鳍天竺鱼(Apogonichthys carinatus)、黄斑鲾(Leiognathus bindus)、皮氏叫姑鱼(Johnius belengeri)、大头白姑鱼(Argyrosomus macrocephalus)、鯻(Therapon thraps)、棕斑腹刺魨(Gastrophysus spadiceus)和麦氏犀鳕(Bregmaceros macclellandi)。     

瓦努阿图周边海域长鳍金枪鱼渔场分布及其与表温关系

海表温(SST)是影响渔场的重要环境因子.根据2008年我国冰鲜金枪鱼延绳钓船在瓦努阿图周边海域的生产统计数据,结合卫星遥感获得的SST资料,分析了长鳍金枪鱼各月渔场时空分布及其与SST的关系.K-S检验表明,长鳍金枪鱼渔场形成与SST关系密切.     

固相萃取-气相色谱/质谱法检测卤水中有机物的种类

建立了卤水中有机物的固相萃取-气相色谱/质谱分析方法。首先用石墨化碳黑柱对盐湖卤水的有机物进行富集,采用气相色谱-质谱(GC-MS)以扫描离子和选择离子检测模式进行检测。回收率标记物在0.1～1 mg/L范围里线性关系良好,相关系数R=0.998 7;其回收率处于74.00%～96.00%之间,相对标准偏差(RSD)为10.9%。最后用优化的方法检测了所富集的有机物。     

钦江河口潮滩红树林群落空间分布

红树林群落是热带亚热带河口有特色的生态系统,在消浪促淤及存储碳方面具有重要价值。但受到全球海平面上升与人为干扰影响,红树林生境受到破坏,群落结构脆弱。基于此,本文以现场校核的无人机正射影像为数据源,结合历史遥感影像、钦江河口水体盐度与潮滩沉积物采样分析,研究钦江河口潮滩红树林群落空间分布格局及主控要素。结果表明：（1）潮滩分布的红树植物主要有桐花树、无瓣海桑等,其中桐花树为绝对优势种的“纯红树植物”群落,自河口向沿感潮河段逐渐发展成“红树植物—半红树植物”群落与“红树植物—半红树植物—非红树植物”的混合植物群落。（2）桐花树是钦江河口红树林向海发育的前沿先锋树种,二年生桐花树苗分布最前沿高程低于当地海平面0.11 m,当年胎生苗分布最前沿高程为当地海平面以下0.37 m;桐花树也是钦江感潮段上溯分布极限的树种,当年胎生苗上溯分布极限为距河口10.18 km。（3）潮位与盐度是控制红树林群落在钦江河口分布的主要因子,沉积物粒径的粗细影响红树植物生长与发育。研究成果可为热带山区型河口潮滩红树林保护与红树林生态修复工程提供重要理论和技术指导。