Larval dispersion of the estuarine crab Neohelice granulata in coastal marine waters of the Southwest Atlantic

The estuarine brachyuran crab Neohelice granulata export their larvae from the parental intertidal population of the Mar Chiquita coastal lagoon, and probably other populations, to marine waters. The degree of larval dispersion or self-recruitment of populations is unknown. We evaluated the presence of all larval stages of N. granulata in coastal waters of Argentina between 37.9° and 35.8° S, at two different spatial scales: a broad scale of tens to hundreds of kilometers from the Río de la Plata estuary in the north, to Mar Chiquita lagoon in the south, and a small scale of hundreds of meters to some kilometers around the mouth of Mar Chiquita, during spring and summer. Additionally, we registered the larval composition and density at San Clemente creek population, in Samborombon Bay (Río de la Plata estuary), every 3 h along a 30-hour period. Evidence indicates that larval release of N. granulata is temporally synchronized with nocturnal ebb tides and all development from Zoea I to Zoea IV occur in areas close to the parental population, even with very different oceanographic characteristics. A possible mechanism based on salinity selection and wind-driven transport is proposed for such behavior, and some considerations related to the connectivity of present populations are made.     

东北西部碱水水域对虾生存和生长与K~+,Ca~(2+),Mg~(2+),Na~+/K~+及M/D的关系

利用盐碱化湖泊和池塘水进行凡纳滨对虾(Litopenaeus vannamei)淡化幼虾的生长试验,研究对虾生存和生长与水环境 K+,Ca2+,Mg2+,Na+/K+ 及 M/D(离子系数)的相关性,为内陆碱水水域养殖提供科学依据.结果表明,在碱度为 10.32～38.50 mmol/L,盐度 1.02～3.34,pH 8.5～9.5 的试验水环境下,幼虾存活率差异极显著(P< 0.01),体重特定生长率(SGRW)无显著性差异(P>0.05).存活率和 SGRW 值与水环境因子间的相关性存在因子间的互作效应,其简单相关系数都受到其他因子组合的负效应影响.存活率与 K+,Ca2+,Mg2+ 质量浓度和 Na+/K+ 及 M/D 的相关性不显著;SGRW 值与 Ca2+,Mg2+ 质量浓度和 Na+/K+ 及 M/D 显著相关,与 K+ 质量浓度的相关性很小(P>0.05).投施 KCl,CaCl2 及 MgCl2,可以改善内陆碱水水域 K+,Ca2+,Mg2+,Na+/K+ 及 M/D 的组成结构,有利于对虾生存与生长.     

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。     

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.     

Processes influencing iron distribution in the coastal waters of the Tsugaru Strait,Japan

We report measurements of iron, nutrients, dissolved oxygen, humic-type fluorescence intensity and chlorophyll a concentrations in the coastal waters at the inflow (western) and outflow (eastern) ends of Tsugaru Strait (Japan) in June 2003 and 2004. Two different water masses (intensive eastward flow “subtropical Tsugaru Warm Current Water (TWCw)” and weak westward flow “subarctic Oyashio Water (OW)”) were observed at the eastern end of the strait. TWCw at the southern part of the eastern strait was vertically homogeneous with a uniform concentrations of iron (0.7–1.1 nM for labile dissolved Fe and 14–20 nM for total dissolvable Fe in 2003) as well as other chemical, biological and physical components throughout the water column of 200 m due to strong vertical mixing in the strait. The degree of mixing in the Tsugaru Warm Current (TWC) is predominantly affected by diurnal tidal current, which is strong during the period of tropical tides and weak during the period of equinoctial ones. The especially strong vertical water mixing in 2003 is caused by large dissipation energy input due to the bottom friction of passage-flow through the strait and tidal current. At the northern part of the eastern strait, the fresh surface layer overlying the OW and the deep-bottom waters in 2003 contained large concentrations of dissolved iron, resulting from iron supplied from river runoff and shelf sediments, respectively. These results suggest that the most important mechanism for transporting iron in the strait is the strong vertical water mixing due to the tidal current, and that the iron sources in the coastal waters are the organic-associated, iron-rich freshwater input into the surface water.     

智利外海茎柔鱼生物学特性的初步研究

根据2007年1月和5～6月我国鱿钓船在智利外海的调查数据,对茎柔鱼生物学特性进行初步分析。结果表明:该地区茎柔鱼胴长范围287～702 mm,优势胴长为380～430 mm,占64.2%;体重范围0.63～11.3 kg,优势体重为0.5～2.0 kg,占75.6%;调查海区渔获个体自西向东、自南往北呈现增大趋势;依据胴长组成推断调查海域可能存在3个群体。生长指数大于3,与秘鲁外海茎柔鱼相近;雌雄性比约为3:1,性腺成熟度以Ⅰ期为主,占92%;摄食等级0～2级为主,约占73%;当地时间00:00后摄食量增大,胃含物以鱿鱼和中上层小型鱼类为主。     

Atmospheric correction of ocean color imagery over turbid coastal waters using active and passive remote sensing

This paper demonstrates an atmospheric correction method to process MODIS/Aqua (Moderate-resolution Imaging Spectroradiometer) ocean color imagery over turbid coastal waters with the aid of concurrent CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization) aerosol data, assuming that there exists "nonturbid" water in the study area where MODIS aerosol optical properties can be retrieved accurately. Aerosol properties from CALIOP measurements were obtained and related to those from MODIS. This relationship, combined with CALIOP aerosol data, was extended to turbid water to derive MODIS aerosol properties, where atmospheric correction using MODIS data alone often fails. By combining MODIS and CALIOP data, aerosol signals were separated from the total signals at the satellite level, and water-leaving radiances in turbid waters were subsequently derived. This method was tested on several MODIS/Aqua ocean color images over South China turbid waters. Comparison with field data shows that this method was effective in reducing the errors in the retrieved water-leaving radiance values to some extent. In the Zhujiang (Pearl) River Estuary, this method did not overestimate the aerosol effects as severely, and provided far fewer negative water-leaving radiance values than the NASA (National Aeronautics and Space Administration) default methods that used MODIS data alone.