泉州湾水体结构的潮周期变化

泉州湾6个站点的观测数据显示：内湾涨潮流历时由底层向表层逐渐变短,而落潮流历时则逐渐变长;同时,各个站点实测的盐度水深结构也具有明显的潮周期变化特征,这可能与局地水体的层化和混合机制的交替变化密切相关．进一步定量分析S2站位上影响水体结构变化的四种机制发现：外湾的河口环流作用与潮汐张力、风混合以及潮汐混合作用相比要小一个量级．在一般天气条件下的大潮周期,潮汐混合与潮汐张力相互竞争是导致水体结构交替变化的根本原因;小潮周期由于潮流混合作用减弱,水体层化现象得以持续较长时间,风的搅动在特定时刻可以起到削弱层化结构的作用．     

从海岸地貌学看河海划界的可操作性

根据河海划界的可操作性的要求,探讨了海岸地貌学指标在河口区划分中的作用,并通过对河口区与河流、海洋之间的动态联系的阐述,提出河口区管理方式的建议.河口是海岸带陆海相互作用的典型环境,具有物理、化学、地质、生物和环境等多种复杂动力学过程,每一个河口都是高度个性化的.在为数不多的体现河口共性的参数中,海岸地貌学指标可用来确定河口区的内、外边界.根据河流水力学特征和河口过程的可容空间范围特征,河口-河流的分界点可用B-L曲线(B为河岸宽度,L为距离原点沿河流轴线的累积长度)上的拐点位置来表示.而按照河口为"半封闭水域"的定义,河口-海洋分界线可采用围封河口水域的海岸线的包络线.河口水域受到河流和海洋的双重影响,且河口区的自然演化和人类开发活动也会影响河流和海洋.因此,在我国河口区管理上应建立海洋和其他管理部门之间的协调机制.     

舟山群岛东部青浜岛海域海底麻坑地貌及其成因分析

海底麻坑是由地层中流体向海底快速喷发或缓慢渗漏所形成的一种凹陷地貌,对其形态及成因机理进行深入研究具有重要意义.本研究基于高分辨率多波束地形、侧扫声纳、浅地层剖面及多道地震探测数据,对舟山群岛东部青浜岛海域发育的麻坑及其微地貌进行研究,分析表明:研究区发育有3个大型麻坑,并受到NE—SW向底流的改造而出现不同程度沿此方...     

华南近岸海域水质评价及其影响因素

以华南沿海32个地市为研究对象,首先基于单一要素评价和综合水质指数法对其近岸海域的水环境质量进行分析,再采用典范对应分析和逐步线性回归探究了各类影响因素与水质指标间的相关性.结果表明:2017年华南近岸海域的主要污染要素为无机氮(N)、活性磷酸盐(P)和悬浮物(SS),严重超标现象主要出现在福建厦门、宁德、福州,广西钦...     

闽东近海游泳动物群落组成、资源量与生物多样性的时空格局研究

采用底拖网方法调查研究了闽东近海春季(5月)和秋季(10月)游泳动物群落组成、生物多样性、资源密度及时空分布格局等问题。调查中出现游泳动物70种(鱼类47种,甲壳类18种,头足类5种),隶属于15目40科64属,以鲈形目种类最多(25种)。鱼类是主要游泳动物群落,春季鱼类个体数和重量分别占总渔获的66.4%和72.3%,甲壳类分别占比33.4%和26.9%,头足类分别占比0.2%和0.8%;秋季,上述三个类群在总渔获中的占比分别为56.6%和60.4%、42.0%和37.8%以及1.4%和1.8%。春季优势种包括红狼牙虎鱼(Odontamblyopus rubicundus)、三疣梭子蟹(Portunus trituberculatus)、孔虎鱼(Trypauchen vagina)等10种,秋季优势种为龙头鱼(Harpadon nehereus)、三疣梭子蟹、六指马鲅(Polynemus sextarius)等7种;两个季节共有优势种包括三疣梭子蟹、日本 (Charybdis japonica)、龙头鱼、棘头梅童鱼(Collichthys lucidus)和六丝钝尾虎鱼(Amblychaeturichthys hexanema)5种。秋季的生物多样性指数和均匀度指数高于春季。春季平均资源密度为1013.7kg/km~2和10.2×10~4ind/km~2,高于秋季的平均值(899.0kg/km~2和6.6×10~4ind/km~2)。总体而言,鱼类是闽东近海主要的游泳动物类群,其资源密度从近岸向外海呈降低趋势,春季的资源密度高值出现在闽东外海中部水域,秋季高值则出现在南部的闽江口等水域;其春季的优势种种类多于秋季,存在一定程度季节性更替现象。     

海底管道在位状态调查实践

根据调查设备搭载器的不同,将海底管道在位状态调查方法归为船载、自治水下机器人搭载(AUV 搭载)和无人遥控潜水器搭载(ROV搭载)三类;在浅水段采用船载调查,在深水段采用AUV搭载调查,在此基础上进行重点关注区域筛选,开展ROV调查,最后进行整体评价和分析对比,这种^“(船载/AUV)+ROV^”组合模式很好地实现了多种调查方法的优势互补。实际上,采用AUV搭载进行海底管道在位状态调查在国内业界尚属首次。调查所取得的管道位置、埋深、周边障碍物的分布以及管道人工处理情况等成果,为后期开展管道维护工作提供了重要的基础数据。此次成功实践可为以后从浅水到深水的管道在位状态调查提供经验和借鉴。     

Salt marsh plants (Juncus maritimus and Scirpus maritimus) as sources of strong complexing ligands

This work aimed to evaluate, in vitro, the capability of roots of salt marsh plants to release strong Cu-complexing ligands and to ascertain whether Cu contamination would stimulate ligands' exudation or not. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants were collected seasonally, four times a year in 2004, during low tide. After sampling, plant roots were washed for removal of adherent particles and immersed for 2 h in a solution that matched salinity (3) and pH (7.5) of the pore water from the same location and spiked with Cu²⁺ in the range 0–1600 nM to obtain plant exudates. In the final solutions as well as in sediment pore water total dissolved Zn and Cu, Cu-complexing ligand concentrations and the respective conditional stability constants (K_CuL^′) values were determined by voltammetry. This study demonstrated that plants are able to release, in a short period of time, relatively high amounts of strong Cu-complexing ligands (56–265 nmol g_root⁻¹), which differed among plants and sampling site but were independent of the season. Cu contamination did not stimulate exudation of Cu-complexing ligands. On the other hand, in media contaminated with Cu both plants accumulated relatively high amounts (29–83%) of the initially dissolved Cu, indicating that they have alternative internal mechanisms for Cu detoxification. Cu exchange between roots and medium (either accumulation in contaminated medium or release in the absence of Cu) was more intense for S. maritimus than for J. maritimus. It was observed that exudate solutions obtained in the absence of added Cu and sediment pore water (the densities of roots observed inside the salt marsh where comparable to those used in the in vitro experiments), displayed similarities in terms of total dissolved metals, Cu-complexing ligands concentrations, values of K_CuL^′ (12 < log K_CuL^′ < 14), as well as patterns of variation among seasons (only observed for Zn). These results are novel and point out that salt marsh plants may be the source at least partially of the strong organic ligands found in the sediment pore water in shallow marginal areas. The capability of salt marsh plants to release strong organic ligands into the environment, conjugated with their known capacity to oxidize anaerobic sediment around roots, indicate that these plants can play a role in controlling metal speciation in the water/sediment interface.     

Estuarine classification and response to nitrogen loading: Insights from simple ecological models

Estuaries exhibit a large range in their responses to nitrogen loadings determined in part by characteristics of the driver, such as magnitude and frequency, but also by such intrinsic characteristics as physical/chemical factors (e.g., depth, volume, hypsometry, salinity, turbidity) and biological factors (e.g., nature of ecological communities, trophic interactions). To address the richness of estuarine response to driver variables, the aim ultimately is to establish a simple estuarine classification scheme, beginning with a river-dominated subset of estuarine systems and focusing on the role of water residence time in the estuary. Residence time (or flushing time) is related to other drivers (streamflow, nutrient, and sediment loads) and drives much of the biological response of estuaries because of flushing effects on plankton, temperature, nutrients, and light. Toward this goal, nutrient–phytoplankton–zooplankton (NPZ) models have been used to examine a range of subjects including effects of nutrient limitation and zooplankton predation on phytoplankton dynamics and fish predation. This class of model can admit a wide range of behavior, including multiple steady-states and oscillatory behavior. The NPZ equations include terms for nutrient recycling, phytoplankton settling, benthic regeneration, and zooplankton mortality. Analysis of the equations suggests that both the nature of nitrogen loading (i.e., whether it is correlated with discharge or independent of it) and residence time are critical in determining the steady-state response of the system.     

Stable isotopes in juvenile marine fishes and their invertebrate prey from the Thames Estuary,UK, and adjacent coastal regions

Estuaries are regarded as valuable nursery habitats for many commercially important marine fishes, potentially providing a thermal resource, refuge from predators and a source of abundant prey. Stable isotope analysis may be used to assess relative resource use from isotopically distinct sources. This study comprised two major components: (1) development of a spatial map and discriminant function model of stable isotope variation in selected invertebrate groups inhabiting the Thames Estuary and adjacent coastal regions; and (2) analysis of stable isotope signatures of juvenile bass (Dicentrarchus labrax), sole (Solea solea) and whiting (Merlangius merlangus) for assessment of resource use and feeding strategies. The data were also used to consider anthropogenic enrichment of the estuary and potential energetic benefits of feeding in estuarine nursery habitat.     

Spatial and temporal distribution of chromophoric dissolved organic matter (CDOM) fluorescence and its contribution to light attenuation in UK waterbodies

Vertical attenuation of light through the water column (K_d) is attributable to the optically active components of phytoplankton, suspended particulate material (SPM) and chromophoric dissolved organic matter (CDOM). Of these, CDOM is not routinely monitored and was the main focus of this study. Concentrations and spatio-temporal patterns of CDOM fluorescence were investigated between August 2004 and March 2006, to quantify the correlation coefficient between CDOM and salinity and to better characterise the contribution of CDOM to K_d. Sampling was conducted at a broad range of UK and Republic of Ireland locations; these included more than 15 estuaries, 30 coastal and 70 offshore sites in the southern North Sea, Irish Sea, Liverpool Bay, Western Approaches and the English Channel.An instrument package was used; a logger with multi-sensor array was deployed vertically through the water column and concurrent water samples were taken to determine salinity, CDOM fluorescence and SPM. Surface CDOM fluorescence values ranged between 0.05 and 16.80 S.Fl.U. (standardised fluorescence units). A strong, negative correlation coefficient of CDOM to salinity (r² = 0.81) was found. CDOM absorption (aCDOM_λ) was derived from fluorescence measurements and was in the range 0.02–2.2 m⁻¹ with mean 0.15 m⁻¹. These results were comparable with direct measurements of aCDOM_λ in the same geographic regions, as published by other workers.Spatial differences in CDOM fluorescence were generally explicable by variation in salinity, in local conditions or catchment areas; e.g. CDOM at the freshwater end was 3.54–11.30 S.Fl.U., reflecting the variety of rivers sampled and their different catchments. Temporal changes in CDOM fluorescence were related to salinity. A significant and positive correlation was found between CDOM and K_d, and although CDOM was found to be less influential than SPM on K_d, it was still of significance particularly in coastal and offshore waters of lower turbidity.