温度、光照强度和pH对雨生红球藻光合作用和生长速率的影响

采用测定净光合放氧速率的方法研究了温度、光照强度和pH对 4株雨生红球藻光合作用和生长繁殖速率的影响。结果表明 ,温度、光照强度和pH对雨生红球藻的光合作用和生长速率的影响十分显著 ;4株雨生红球藻光合作用的最适温度、光饱和点和pH分别为 :Haematococcuspluvialis 2 6 :1 5℃ ,2 5 0 μmol/(m2 ·s)和pH7 0 ;Haematococcuspluvialis 3 0 :2 0℃ ,2 0 0 μmol/(m2 ·s)和pH8 0 ;Haematococcuspluvialis 3 4 :1 5℃ ,2 0 0 μmol/(m2 ·s)和pH7 0 ;Haematococ cuspluvialisWZ :1 0℃ ,1 40 μmol/(m2 ·s)和pH6 0。雨生红球藻细胞数量的增加与光照时间成正比。初步认为H pluvialis3 0、H pluvialis2 6和H pluvialisWZ是 3个有潜力适合于大规模生产的藻种。     

青岛三种海产红藻的光合和呼吸特性的初步研究

于1981年在青岛近海采集真江食、石花莱和角叉菜样品，用氧电极法测定它们在不同生长季节和发育阶段的光合和呼吸速率，并研究不同温度对其光合和呼吸速率的影响，同时计算出它们的呼吸温度系数。结果表明，3种红藻具有典型的潮间带海藻的光合特性，即高光饱和点为600—1000μE／（m2·s），较高的光补偿点为12－40μE／（m2·s）和较高的光合适温≥25℃。温度对3种红藻的光合和呼吸的影响均很明显，在5，15，25℃下测试，它们的最高光合和呼吸速率都出现在25℃。3种红藻的呼吸温度系数（Q10），在5－15℃较高，为1．4－5．5在15－25℃较低，为1．1－2．7。说明它们在低温下的呼吸受温度变动影响较大。经计算3种红藻在适宜生长温度下的净光合速率：角又菜和真江蒿在15℃分别为4．90O2mg／（g·h）和8．14O2mg／（g·h）；石花菜在25℃为11．87O2mg／（g·h），在3种红藻中最高。这说明，石花菜的光合效率并不象人们预料的那样低，其秋季幼体在25℃，1000μE／（m2·s）光强下，净光合速率达到19．19O2mg／（g·h）。看来在自然界石花菜生长缓慢主要是由于生境中低光照强度和较低水温所致。     

底栖海藻比较光合作用研究 Ⅱ.潮间带褐藻的光合作用与光强的关系

沿岸带底栖海藻的垂直分布情况比较复杂。在黄海沿岸潮间带不仅有绿藻,而且有许多褐藻和红藻,有些褐藻不仅生长茂盛而且数量很多。显然,它们对于潮间带的这种特殊的生态环境是能够适应的。 底栖褐藻的光合作用与光照条件的关系是决定其垂直分布的重要因素之一。Kage yama和Yokohama测定过分别生长在潮间带中部、低潮线和低潮线下15米深处的四种褐藻的光合作用与光强的关系。他们认为底栖褐藻的光合作用也有适应高光强的种类,     

海南岛的江蓠资源及其开发现状

我国第二大岛——海南岛位于东经108°36′—119°00′、北纬18°09′—20°16′;西临北部湾、东部与南部濒临南海、北靠大陆和雷州半岛只有琼州海峡一水之隔;岸线长达1447千米、有大小港湾60多个和可供海水养殖的滩涂约20万亩。该岛气候温和,热带、亚热带性海藻生长繁茂,资源丰富。经济价值高的品种有凝花菜(Gelidiella)、江蓠(Gracilaria)、凤尾菜(G.eucheumoides)、马尾藻(Sarga-     

海藻化学名词解释

藻胶(Phycocolloid)海藻中的绿藻、红藻和褐藻,都含有多种高分子多糖。其中褐藻和红藻所含多糖分散于水中呈高粘度或高凝胶强度,具有一定的工业价值。藻胶通常就是指这些有经济价值的海藻多糖。 褐藻胶(Algin)是从褐藻加碱提取出来的一种水溶性高粘度胶体。为各种褐藻所共同含有的一种细胞间多糖。褐藻胶包括水溶性褐藻酸钠、钾、铵盐以及水不溶性褐藻酸及其钙、铁盐等,但在市场上     

青岛潮间带大型底栖海藻群落的研究

在青岛潮间带布设了显浪咀、太平角和石老人3个断面,进行了为期1 a(2006年8月～2007年11月)的大型底栖海藻资源调查研究.结果表明:1. 青岛潮间带大型底栖海藻群落的种类组成中红藻种类最多,其次是褐藻,绿藻最少.2. 群落中大型底栖海藻的生物量有明显的季节变化:春季>夏季>秋季>冬季;生物量在垂直分布上表现出中、低潮带均大于高潮带;在水平分布上无明显差异.3. 底栖藻类群落优势种无季节性变化,第一优势种为孔石莼.4. 采集到大型底栖海藻43种,其中红藻门22属24种,占55.8%;褐藻门9属11种,占25.6%;绿藻门6属8种,占18.6%.     

开发海藻饲料添加剂大有可为

将海藻加工成海藻粉作饲料添加剂喂养禽畜,不但可大大加快禽畜的生长,而且具有广阔的市场发展前景。 海藻是海洋中能进行光合作用的自养植物,按其藻体所呈不同颜色,又可分为红藻、绿藻、褐藻、蓝藻、金藻等,品种繁多,据记载,其中有经济价值的品种达100种以上。海藻含有很高的营养价值,据研究分析,其中蛋白质含量为8％～12％,高的达到17％,所含海藻胶、淀粉、甘露醇和纤维素等无氮有机物占30％～60％。     

4 种经济海藻脂肪酸组成分析

采用改进的Bligh-Dyer法提取脂溶性成分,气相色谱-质谱联用法(GC-MS)进行分离和鉴定,C19:0内标确定总脂及各组分含量,研究了鼠尾藻(Sargassum thunbergii)、浒苔(Enteromorpha prolifera)、龙须菜(Gracilaria lemaneiformis)和红毛菜(Bangia sp.)4种经济海藻的脂肪酸组成及含量。结果表明,4种海藻都检测出C14-C22脂肪酸,总脂含量在12～19 mg/g之间,不饱和脂肪酸为主要组成成分,含量均超过60%。不饱和脂肪酸中以多不饱和脂肪酸(PUFAs)为主,富含n-3和n-6系列PUFAs,n-6与n-3系列PUFAs之比均低于2。比较4种海藻脂肪酸组成特点表明,鼠尾藻以C16、C18和C20为主要组成成分,具褐藻类脂肪酸组成特征;浒苔以C16和C18为主要组成成分,具绿藻类脂肪酸组成特征;龙须菜和红毛菜以C16和C20类脂肪酸为主,具典型红藻类脂肪酸组成特征,同时二者又有不同之处,分别显示真红藻与原始红藻脂肪酸组成的特点。     

西沙群岛红藻的研究Ⅰ

西沙群岛和南沙群岛、中沙群岛、东沙群岛一样,历来就是中国领土的一部分,我们坚决支持我国政府一再声明的这一严正立场。 西沙群岛红藻的研究始于樊恭炬和王永川(1974)发表的“我国西沙群岛海藻的研究I.殖丝藻属”。文中把世界上分布较广的暖水性海藻Liagora farinosa Lamx移至一新建立的殖丝藻属,名为Ganonema farinose (Lamx.) Fan et Wang.1975年,樊恭炬等在同一题目的第二篇“Ⅱ.海索面科(红藻门)的一些新种及新纪录”中报告了以下各种： 中国粉枝藻 Liagora sinensis Fan, Wang et Pan 鼓苞粉枝藻 L. setchellii Yamada 纤细粉枝藻 L. filiformis Fan et Li 单轴殖丝藻 Ganonema pinnatiramosa ( Yamada) Fan et Wang 疣枝果丝藻 Trichogloeopsis hawaiiana Abbott et Doty 1976年,张峻甫和夏邦美在“中国江蓠属海藻的分类研究”一文中报告了西沙群岛产的弓江蓠Gracilaria artcuata Zanard.和凤尾菜G. eucheumoides Harv.两种经济海藻。 根据上述三个报告,连同记载在待刊稿上的17种,西沙群岛的红藻迄今所知者共有25种。 中国科学院海洋研究所曾于1957、1958、1975和1976年先后四次派出调查队到我国西沙群岛进行海藻调查,采集了大量标本。为了弄清这一岛群的资源情况、海藻种类和区系组成性质并进而探讨与邻近地区海藻区系的亲缘关系等。我们正在对部分红藻进行研究,所得结果将陆续整理发表。 本文报告了下列六种红藻,其中的三种为西沙群岛的新纪录,包括一种为我国新纪录。一种系新种,绝大部分为罕见的红藻。     

关于海南岛几种经济海藻的栽培和利用

海南岛海岸线长达1477公里,有大小港湾60多个,可供海水养殖的面积可达20万亩。在目前,栽培前途大、经济价值高的海藻有凝花菜、麒麟菜、江蓠、凤尾菜、马尾藻、凹顶藻和沙菜等。有些种类,如凝花菜、麒麟菜、凤尾菜等都是我国大陆沿海所没有的特有种类。海南岛的琼海、文昌两县的海水养殖场从事凝花菜、麒麟菜的人工栽培已有20多年的历史,栽培面积增加了近100倍,年产量仅次于我国北方的海带。     

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.     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

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。     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.     

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.     

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.