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1.
Periodical algal blooms result in deposition and release of phosphorus (P) from the sediment into the water. Therefore, during seasonal changes when algal particles begin to settle to the bottom, understanding the behavior and distribution characteristics of the P in sediment is the most important key to manage the water quality of the Saemangeum Reservoir. In this study, the variation of water quality and sediment composition including chlorophyll-a (Chl-a) and P was investigated to determine the interaction between water and sediment. The study focused primarily on algal particle sedimentation that affects the P release and mineralization of sediment. The Chl-a concentration in water showed a sharp decline in October when the algae began to die in the fall, and afterward the concentration of chemical oxygen demand (COD) and total P (TP) in the sediment increased due to the sedimentation of decaying algal particles in November. During the same period of time, the readily bio-available P (RAP) in the sediment showed a drastic increase in the upper region where the Chl-a concentration of water was high. In sequence, the high RAP zone shifted from the upper region to the lower region in the early winter. The RAP shift was considered to be derived from the physical flow of the overlying water from which the decomposing algae settled on the surface of the sediment. The Saemangeum Reservoir was constructed recently; therefore, all the types of inorganic P fractions except soluble reactive phosphorus (SRP) that exist on the bottom surface of the lake and the marsh's sediment layer were not sufficient to significantly influence the overlying water. On the other hand, the released P from the algae was distinct and sensitive to the seasonal change. In conclusion, the algal particle sedimentation was important to control eutrophication rather than P release from the mineralized inorganic P of the sediment surface layer in the Seamangeum Reservoir.  相似文献   
2.
中国近海藻毒素及有毒微藻产毒原因种调查研究进展   总被引:2,自引:0,他引:2  
麻痹性贝类毒素在我国近海污染问题已十分突出,基本呈现逐年加剧的趋势。20世纪90年代,南海麻痹性贝类毒素污染较重; 21世纪初,北黄海麻痹性贝类毒素污染较重;近几年,渤海和福建近海麻痹性贝类毒素污染较重;可产生麻痹性贝类毒素的微藻有亚历山大藻和裸甲藻等。采用小鼠生物法检测我国近海腹泻性贝类毒素超标率32%左右,采用液相色谱/质谱法检测,仅有3起超标的研究报道;现行小鼠生物法检测腹泻性贝类毒素假阳性问题十分突出,应尽快废除;腹泻性贝类毒素均是脂溶性的,脂溶性海洋生物毒素在我国近海常年可检出,偶有虾夷扇贝毒素和鳍藻毒素超标现象。可产生脂溶性毒素微藻有鳍藻和原甲藻及网状原角藻等。失忆性贝类毒素在我国近海常有检出,但无超标现象;产毒微藻有拟菱形藻等。西加鱼毒素在我国南海污染较重,但毒素标准物质的匮乏,限制了西加鱼毒素的调查研究;至今尚未确定产生西加鱼毒素的微藻。酶联免疫吸附法和液相色谱串联质谱法相结合已成为藻毒素快速准确检测成熟的技术,逐渐代替小鼠生物法和液相色谱法。  相似文献   
3.
浙江南麂岛海域是我国近岸贝类的重点养殖区,近年来一直遭受脂溶性贝类毒素(lipophilic shellfish toxins,LSTs)的污染,威胁着人类健康。为了建立有效的食品安全预警方法,本研究利用固相吸附毒素跟踪技术(solid phase adsorption toxin tracking,SPATT)在该海域进行了为期一年的野外监测和LSTs毒素分析。结果表明:7种LSTs毒素在SPATT(DIAION?HP20)中被检出,分别是大田软海绵酸(okadaic acid,OA)、鳍藻毒素-1(dinophysistoxin-1,DTX-1)、虾夷扇贝毒素(yessotoxin,YTX)及其衍生物homo YTX、扇贝毒素-2(pectenotoxin-2,PTX-2)及其衍生物7-epi-PTX2sa和环亚胺毒素(gymnodimine,GYM);有8种毒素在厚壳贻贝(Mytilus galloprovincialis)中被检出,分别是OA、DTX1、homo YTX、PTX2、7-epi-PTX2sa、GYM、原多甲藻酸贝类毒素-3(azaspiracid-3,AZA-3)和虾夷扇贝毒素衍生物45-OH-homo YTX。整体而言,SPATT(HP20)中吸附的毒素种类与贝肉中监测出的毒素种类大体上一致,且两者间OA、DTX1和PTX2的浓度在时间上具有较好的相关性,可见SPATT(HP20)对这些LSTs毒素具有较高的灵敏度,有望作为水体中LSTs毒素的预警监测材料。南麂岛海域LSTs分布特征明显,夏季最高,其次是春秋季,冬季最低,其中2014年夏季贝肉中OA毒素含量高达77.19ng/g贝肉,超出国家限量标准(45ng/g贝肉)比例达11.76%,为浙江南麂海域贻贝的食用安全带来隐患。  相似文献   
4.
气象条件对滇池水华分布的影响   总被引:3,自引:1,他引:2  
使用MODIS卫星资料,利用假彩色合成法和归一化植被指数法对滇池蓝藻水华进行监测,得到滇池水华的分布特征是:初现于5月,7月最盛,5—10月均有分布,盛时滇池水华分布区域直至南部海口一线。滇池水华分布总体北部最多,湖岸高于中心湖区,西岸高于东岸和南岸。在营养盐条件满足的条件下,高温对水华有促进作用,但不是决定因素。充足的日照是水华形成的必要条件。降水通过改变水温及日照对水华有抑制作用。小风(小于3 m/s)利于水华形成,大风对水华尤其是稀薄水华分布影响较大。气象条件通过相互影响,共同作用对水华产生影响。  相似文献   
5.
Macroalgal blooms of Hypnea musciformis and Ulvafasciata in coastal waters of Maui only occur in areas of substantial anthropogenic nutrient input, sources of which include wastewater effluent via injection wells, leaking cesspools and agricultural fertilizers. Algal δ15N signatures were used to map anthropogenic nitrogen through coastal surveys (island-wide and fine-scale) and algal deployments along nearshore and offshore gradients. Algal δ15N values of 9.8‰ and 2.0-3.5‰ in Waiehu and across the north-central coast, respectively, suggest that cesspool and agricultural nitrogen reached the respective adjacent coastlines. Effluent was detected in areas proximal to the Wastewater Reclamation Facilities (WWRF) operating Class V injection wells in Lahaina, Kihei and Kahului through elevated algal δ15N values (17.8-50.1‰). From 1997 to 2008, the three WWRFs injected an estimated total volume of 193 million cubic meters (51 billion gallons) of effluent with a nitrogen mass of 1.74 million kilograms (3.84 million pounds).  相似文献   
6.
Temperate and tropical shallow lakes differ in several fundamental aspects with respect to management of eutrophication. High altitude tropical shallow lakes are a special case, showing similarities with temperate and tropical lakes. We studied the ecology of the eutrophic high-altitude tropical lake Yahuarcocha in the Ecuadorian Andes and evaluated the potential of biomanipulation to control eutrophication. With a toxin-producing Cylindrospermopsis bloom, low Secchi depth and low submerged macrophyte cover, Yahuarcocha is clearly in a turbid ecosystem state. Relatively low nutrient concentrations should theoretically allow for a shift to a clear water state through biomanipulation. Top-down control of phytoplankton by zooplankton, however, is complicated by the (1) absence of predatory fish, (2) fish community dominated by small poecelid species, (3) lack of a refuge for zooplankton from fish predation within the macrophytes, and (4) persistent, grazing resistant bloom of the cyanobacterium Cylindrospermopsis. In these aspects, lake Yahuarcocha is more similar to tropical shallow lakes, probably because water temperature is high relative to the mean air temperature and because of the absence of a cold season. The fish and macrophyte communities consisted almost entirely of exotic species. The exotic fish species probably stabilized the turbid state in the lake.  相似文献   
7.
一种棕囊藻的形态特征与毒素分析   总被引:42,自引:4,他引:38  
于1997年11月,在广东省汕头地区饶平县海面采集棕囊藻,采用显微观察和光谱分析方法,进行形态特征与毒素结构的研究。结果表明,该种藻具有两处不同的藻体形态:一种是不运动的球形群体,外具胶质被,群体内的细胞有近千至数万个,每个细胞有2-3个黄褐色的叶绿体;另一种是游动的单细胞,具有两根几乎等托的鞭毛和一根短的定鞭丝,常呈球形,将反复冻融或冷冻干燥的藻细胞经有机溶剂提取,用新鲜牛血球测定显示出强的溶血  相似文献   
8.
有毒赤潮藻及其毒素的危害与检测   总被引:6,自引:0,他引:6  
海洋中可引发赤潮的藻类约有300种,其中有毒赤潮藻为80种左右。现已知道的赤潮藻主要毒素有麻痹性贝毒、腹泻性贝毒、记忆缺失性贝毒、神经性贝毒、西加鱼度和溶血性毒素,前5种毒素的结构已经基本得到证实。有毒赤潮藻的毒素可以在海洋生物体内积累,人类误食含有藻毒素的食品时可能中毒,严重者还可能死亡。海洋有毒赤潮藻及其毒素的检测已经成为当今全球赤潮研究和监测的重要内容之一,可以通过形态学分类方法、分子生物学技术(遗传探针)和免疫学检测技术对有毒赤潮藻进行检测;可以通过生物学、物理化学检测方法和神经受体结合、免疫学检测技术对赤潮藻毒素进行检测。  相似文献   
9.
The rocky outcrops irregularly scattered in the sandy‐muddy sea bed of the Northern Adriatic, formed by a base rock and a superimposed concretion of vegetal and animal organisms, are considered an infralittoral coralligenous habitat, according to the most recent definition. In the last four decades, research has mainly concentrated on their geology because of the question of the origin of the base rock – very similar to beachrock – which has only recently been attributed to sedimentary cementation induced by methane seeps. Studies on their macrobenthic assemblages have also been published recently, but true comparisons among them are difficult because they mostly refer only to a few selected phyla or to short‐term observations. Very few papers deal with the whole of the animal and plant communities, including all taxonomic groups and the most important environmental variables. On the basis of the literature data concerning several outcrops in the Gulf of Venice, we suggest that the Adriatic reefs differ slightly from the classic deeper coralligenous assemblages around the Mediterranean coast because they have smaller concretions of algae builders. We also suggest that the Northern Adriatic coralligenous reefs are younger than the other reefs occurring in the Mediterranean Sea.  相似文献   
10.
近年来,由于工农业和沿海养殖业的发展,我国近海污染逐年加重,赤潮发生频次增加。因此,监测近海污染和赤潮发生预报方法研究势在必行。本文用NOAA/AVHRR数据,分析近海水域污染状况,并探索赤潮发生的预报方法。  相似文献   
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