中国赤潮的发生趋势和研究进展

通过对中国沿海赤潮发生历史的回顾以及主要赤潮事件的分析,阐明了中国沿海赤潮发生所呈现的趋势,即频率增加,规模扩大,新的赤潮藻种不断出现,有毒赤潮种比例上升,以及有害赤潮危害程度日益增加,且初步分析了赤潮频发的内因和外因,综述了我国科学家在赤潮生消过程监测,赤潮灌的培养生物学和分类学,赤潮藻类的营养动力学及生理生态学特性,赤潮藻类的生活史,赤潮藻类毒素,赤潮的模型和赤潮防治及国际合作等方面工作的进展,指出了研究还存在的不足之处,并对未来赤潮研究和管理提出了建议。     

香港及珠江口海域有害赤潮发生机制初步探讨

回顾了香港及珠江口海域赤潮发生和藻毒素污染的历史及研究状况,结合3种代表赤潮藻种最适光温盐生长实验,4种不同形态氮营养盐对几种常见赤潮藻种生长影响实验,以及不同营养盐,温度,盐度条件下赤潮藻群落变化过程实验,初步探讨了物理,化学,生物等环境因子在香港和珠江口海域赤潮发生中的作用机制。     

浅论赤潮

近年来,我国南北沿海赤潮频发,先后在黄河口(1952年)、辽河口(1957、 1967) 、大沽河口(1977) 、大连湾(1979、 1980、 1981) 、东海(1972) ,湛江(1980) 、香港(1971、 1980、 1986) 等近海水域分别发生夜光藻、中肋骨条藻、毛丝藻、微形原甲藻、颤藻等形成的赤潮。据不完全统计,70年代前,在我国有文字记载的赤潮仅有3次。70年代后,在黄、渤、东、南海近岸海域,发现并有记载的赤潮近30次。不仅给海洋渔业资源和生产造成重大损失,而且给人类健康带来严重影响。如今,随着海洋污染日趋加剧,世界各地赤潮的发生已有与日俱增的趋势。太平洋、大西洋沿岸居民因误食由赤潮污染的     

中国沿海的赤潮问题

统计了中国沿海１９７２～１９９８年的赤潮事件３６０起（香港、台湾省未统计在内）,系统介绍了中国赤潮研究概况和研究机构与组织。对中国沿海的赤潮进行分海区分析。根据海洋学特征,中国赤潮可分为：近岸型（河口和内湾型）、外海型（外洋型）、外来型（外源型）、养殖区型赤潮。根据中国近十多年来发生赤潮的现状,可归纳为４个特点：①频率增高;②持续时间长、范围广和危害增大;③新记录和有毒种类增多;④“双相型”赤潮有上升趋势、类型多样等。     

我国近海赤潮多发区域及其生态学特征

根据有关的研究资料,分析我国近海赤潮多发区分布、主要赤潮生物种类、环境状况及赤潮发生生态学特点.结果表明,我国辽东湾、渤海湾、莱州湾、大连湾、长江口、舟山海域、杭州湾、厦门湾、柘林湾、大鹏湾、珠江口等为赤潮多发区.引发赤潮的因素较多,它与气象、水动力、营养盐及生物环境的变化密切相关,人类活动(如海水养殖、陆源污水排放等)影响加剧近海富营养化是引发赤潮的重要因素;但富营养化并非发生赤潮的唯一条件,低营养海区也可能发生赤潮.目前对诱发赤潮的关键因子及赤潮发生机理,应加强定点长期监测和开展深入研究.     

南海北部沿海夜光藻赤潮的生态模式研究

本文根据１９８０～１９９１年南海北部沿海发生的夜光藻赤潮资料,介绍了夜光藻的生物学特征．生态学特征,从夜光藻发生赤潮的起始、发展、维持和消亡四个阶段分析和探讨其发生机制,提出了夜光藻赤潮的生态模式。研究表明：夜光藻赤潮各阶段的消长过程受到物理、化学和生物因素的制约．这些因素在夜光藻赤潮发生的不同阶段所起的作用是不一样的,其发生机制仍然存在着生物地理学的差异等。     

海洋赤潮水色遥感技术研究进展

海洋水色遥感已成为赤潮探测与监测的重要技术手段之一。文章回顾了赤潮卫星遥感技术的发展历程,阐述了水色遥感的原理--水体的离水辐射及其光谱特征。着重论述了高光谱卫星在赤潮水色遥感中的作用,通过大气校正减少大气和气溶胶对遥感信息的衰减,同时就赤潮发生的海洋学机理进行了探讨。综合分析后指出中分辨率成像光谱辐射计(MODIS)作为图谱合一的新一代卫星传感器将在赤潮的卫星监测研究中发挥及其重要的作用。并对今后赤潮遥感的主攻方向提出了一些建议:拓宽遥感数据来源,与地理信息系统技术结合及加强赤潮的预警研究等。     

1981—2011 年间东海赤潮发生与厄尔尼诺关系分析

分析1981—2011 年东海海域赤潮发生次数、赤潮生物种类数以及与El Niño 关系, 结果表明: 东海的赤潮发生以2000年为界可划分为2 个阶段, 1981—2000 年为第一阶段(初级阶段), 赤潮年均8 次, 赤潮生物种数年均4 种, 总体处于发生频次较低水平; 2001—2011 年为第二阶段(高发阶段), 赤潮发生的频次是第一阶段的6.4 倍, 年均引起赤潮生物种数是第一阶段的2.8倍; El Niño 次年东海赤潮生物种类数相对于El Niño 年平均增加6.6%, 赤潮生物种类数平均增加56.6%, 对El Niño 第三年影响小于第二年。El Niño 年Niño 3.4 指数与次年赤潮生物的种类数变化率相关系数为0.70, 为中等相关水平, 均高于El Niño 当年和第三年, 表明El Niño 将显著影响次年的赤潮生物种类数量。     

广东沿海赤潮的特点及成因研究

列举了广东沿海１９８０－１９９２年发生的６６起赤潮事件并对其进行研究分析,归纳广东沿海赤潮具有频率增多、全年均可发生赤潮,发生赤潮区域扩大,持续时间长和危害程度大,新记录种和有毒赤潮多等特点。并就其成因进行了研究,认为：①广东沿海赤潮种类繁多是赤潮发生的重要原因;②海洋污染和海水养殖业的自身污染是赤潮发生频繁的根本原因;③与季风转换有关密切联系,广东沿海赤潮主要发生在东北季风向西南季风转换时期的３     

海洋围隔生态系中无机氮对浮游植物演替的影响

本文评述了１９９２年秋冬季在厦门进行的一次海洋围隔生态系实验的结果。实验重现了围隔水体连续富营养引发了甲藻赤潮的现象。间歇性的供给无机氮,不会影响浮游植物演替的顺序,但会导致甲藻赤潮出现时间长短和优势种的差异。实验结果还表明,演替过程对甲藻赤潮的形成起着重要的作用。而不同种属甲藻的生活习性和它们的自养能力使它们的生存能力存在差异。这是形成甲藻赤潮优势种的一个主要因素。甲藻赤潮的发生并不完全依靠水体中营养盐浓度的大小。     

Fish Sound Production in the Presence of Harmful Algal Blooms in the Eastern Gulf of Mexico

This paper presents the first known research to examine sound production by fishes during harmful algal blooms (HABs). Most fish sound production is species-specific and repetitive, enabling passive acoustic monitoring to identify the distribution and behavior of soniferous species. Autonomous gliders that collect passive acoustic data and environmental data concurrently can be used to establish the oceanographic conditions surrounding sound-producing organisms. Three passive acoustic glider missions were conducted off west-central Florida in October 2011, and September and October 2012. The deployment period for two missions was dictated by the presence of red tide events with the glider path specifically set to encounter toxic Karenia brevis blooms (a.k.a red tides). Oceanographic conditions measured by the glider were significantly correlated to the variation in sounds from six known or suspected species of fish across the three missions with depth consistently being the most significant factor. At the time and space scales of this study, there was no detectable effect of red tide on sound production. Sounds were still recorded within red tide-affected waters from species with overlapping depth ranges. These results suggest that the fishes studied here did not alter their sound production nor migrate out of red tide-affected areas. Although these results are preliminary because of the limited measurements, the data and methods presented here provide a proof of principle and could serve as protocol for future studies on the effects of algal blooms on the behavior of soniferous fishes. To fully capture the effects of episodic events, we suggest that stationary or vertically profiling acoustic recorders and environmental sampling be used as a complement to glider measurements.     

Effects of a red-tide toxin on fish hearing

Red tides are formed from blooms of marine algae. Among them, the dinoflagellate ( Karenia brevis) that is responsible for Florida red tides can release many types of natural toxins, which cause massive kills of marine animals, including endangered species, and threaten human health. This study was to investigate whether or not a neurotoxin, brevetoxin-3, purified from Florida red tides affects hearing sensitivity of a teleost fish, the goldfish ( Carassius auratus). LD(50) of the goldfish that were intraperitoneally injected with brevetoxin-3 was 0.068 microg g(-1). Evoked auditory brainstem responses were recorded, and hearing threshold was determined using a correlation method. By comparing thresholds of fish before and after a sublethal-dose injection (0.064 microg g(-1)) of the toxin, we found that brevetoxin-3 significantly reduces auditory sensitivity up to 9 dB at low frequencies (100 Hz and 500 Hz), but not at a high frequency (2,000 Hz). Reduction of hearing sensitivity was recovered within 24 h. To our knowledge, this is the first study showing a natural red-tide toxin causes minor hearing loss in vertebrates. Results of the study indicate that brevetoxin-3 could affect hearing capabilities of marine animals that survived exposure to red tides. Mechanisms of the toxin-induced reduction of hearing sensitivity are discussed.     

Review of Florida Red Tide and Human Health Effects

This paper reviews the literature describing research performed over the past decade on the known and possible exposures and human health effects associated with Florida red tides. These harmful algal blooms are caused by the dinoflagellate, Karenia brevis, and similar organisms, all of which produce a suite of natural toxins known as brevetoxins. Florida red tide research has benefited from a consistently funded, long term research program, that has allowed an interdisciplinary team of researchers to focus their attention on this specific environmental issue-one that is critically important to Gulf of Mexico and other coastal communities. This long-term interdisciplinary approach has allowed the team to engage the local community, identify measures to protect public health, take emerging technologies into the field, forge advances in natural products chemistry, and develop a valuable pharmaceutical product. The Review includes a brief discussion of the Florida red tide organisms and their toxins, and then focuses on the effects of these toxins on animals and humans, including how these effects predict what we might expect to see in exposed people.     

Algicidal effect of hybrid peptides as potential inhibitors of harmful algal blooms

Objectives

To biochemically characterize synthetic peptides to control harmful algal blooms (HABs) that cause red tides in marine water ecosystems.

Results

We present an analysis of several short synthetic peptides and their efficacy as algicidal agents. By altering the amino acid composition of the peptides we addressed the mode of algicidal action and determine the optimal balance of cationic and hydrophobic content for killing. In a controlled setting, these synthetic peptides disrupted both plasma and chloroplast membranes of several species known to result in HABs. This disruption was a direct result of the hydrophobic and cationic content of the peptide. Furthermore, by using an anti-HAB bioassay in scallops, we determined that these peptides were algicidal without being cytotoxic to other marine organisms.

Conclusions

These synthetic peptides may prove promising for general marine ecosystem remediation where HABs have become widespread and resulted in serious economic loss.

     

Red to red - the marine bacterium Hahella chejuensis and its product prodigiosin for mitigation of harmful algal blooms

Harmful algal blooms (HABs), commonly called red tides, are caused by some toxic phytoplanktons, and have made massive economic losses as well as marine environmental disturbances. As an effective and environment-friendly strategy to control HAB outbreaks, biological methods using marine bacteria capable of killing the harmful algae or algicidal extracellular compounds from them have been given attention. A new member of the gamma-Proteobacteria, Hahella chejuensis KCTC 2396, was originally isolated from the Korean seashore for its ability to secrete industrially useful polysaccharides, and was characterized to produce a red pigment. This pigment later was identified as an alkaloid compound, prodigiosin. During the past several decades, prodigiosin has been extensively studied for its medical potential as immunosuppressants and antitumor agents, owing to its antibiotic and cytotoxic activities. The lytic activity of this marvelous molecule against Cochlodinium polykrikoides cells at very low concentrations (1 ppb) was serendipitously detected, making H. chejuensis a strong candidate among the biological agents for HAB control. This review provides a brief overview of algicidal marine bacteria and their products, and describes in detail the algicidal characteristics, biosynthetic process, and genetic regulation of prodigiosin as a model among the compounds active against red-tide organisms from the biochemical and genetic viewpoints.     

大型水母迁移规律和灾害监测预警技术研究进展

20世纪80年代以来,全球大型水母灾害发生频率与成灾种类不断增加,已严重影响了近海海洋渔业、沿海工业、滨海旅游业和海洋生态系统,已引起了各国政府高度重视,并且越来越多海洋工作者投身水母迁移等科学研究和监测预警工作中。回顾近年来国内外学者对水母漂移聚集和溯源等迁移规律的研究进展以及水母灾害监测预警工作现状。水母研究为预测预警工作服务,应侧重于开展系统的水母海上和室内试验,建立业务化立体监测体系;加强水母漂移聚集机理研究,建立更完善的水母预警模式。     

Firm-level economic effects of HABS: A tool for business loss assessment

While the economic consequences of HABs may seem obvious, there is little empirical evidence to support the assertion or its magnitude relative to other environmental effects. As scientists learn more about the effectiveness of alternative HAB prevention, mitigation, and control strategies and agencies prepare for a suite of environmental events, information on potential economic losses are needed at the firm level to evaluate and justify continued HAB-related expenditures. To determine the extent of monetary losses that some firms may have incurred due to blooms of Karenia brevis (red tides) in Southwest Florida, 7 years of daily proprietary data were obtained from three beachfront restaurants and supplemented with environmental data from nearby weather stations. The statistical models revealed that reductions in daily sales ranged from $868 to $3734 (13.7%–15.3% on average) when red tide conditions were present. Estimated losses are compared to other environmental events and were found to coincide with those from other studies. The incidence of red tide events (as noted by each restaurant manager) corresponded with cell counts that averaged 180,853 cells/l as measured within 6 miles. Collectively this information supports the hypothesis of localized economic losses and provides a threshold cell count for future loss projections.     

Satellite discrimination of Karenia mikimotoi and Phaeocystis harmful algal blooms in European coastal waters: Merged classification of ocean colour data

The detection of dense harmful algal blooms (HABs) by satellite remote sensing is usually based on analysis of chlorophyll-a as a proxy. However, this approach does not provide information about the potential harm of bloom, nor can it identify the dominant species. The developed HAB risk classification method employs a fully automatic data-driven approach to identify key characteristics of water leaving radiances and derived quantities, and to classify pixels into “harmful”, “non-harmful” and “no bloom” categories using Linear Discriminant Analysis (LDA). Discrimination accuracy is increased through the use of spectral ratios of water leaving radiances, absorption and backscattering. To reduce the false alarm rate the data that cannot be reliably classified are automatically labelled as “unknown”. This method can be trained on different HAB species or extended to new sensors and then applied to generate independent HAB risk maps; these can be fused with other sensors to fill gaps or improve spatial or temporal resolution. The HAB discrimination technique has obtained accurate results on MODIS and MERIS data, correctly identifying 89% of Phaeocystis globosa HABs in the southern North Sea and 88% of Karenia mikimotoi blooms in the Western English Channel. A linear transformation of the ocean colour discriminants is used to estimate harmful cell counts, demonstrating greater accuracy than if based on chlorophyll-a; this will facilitate its integration into a HAB early warning system operating in the southern North Sea.     

北海区海洋生态灾害的主要类型及分布现状研究

本文将海洋生态灾害定义为局部海域一种或少数几种海洋生物数量过度增多引起的海洋生态异常现象,包括赤潮、绿潮、水母旺发和外来种入侵等,根据相关研究及调查资料,探讨了北海区赤潮、绿潮、水母、外来生物入侵等生态灾害发生特点及趋势。结果表明,北海区赤潮和绿潮灾害频发,影响面积较大,渤海北部秦皇岛附近海域赤潮灾害严重,黄海西部山东半岛近岸海域浒苔绿潮灾害严重;水母灾害呈上升趋势,对人体健康威胁较大,北海区滨海城市都曾发生过水母蛰伤致死案例;黄河三角洲区域米草和泥螺入侵扩展速度较快。面对这些海洋生态灾害巨大威胁,北海区亟需加强海洋生态灾害防控研究。     

Applied simulations and integrated modelling for the understanding of toxic and harmful algal blooms (ASIMUTH): Integrated HAB forecast systems for Europe's Atlantic Arc

Reasons for the emergent interest in HABs are abundant, including concerns associated with human health, adverse effects on biological resources, economic losses attributed to recreation, tourism and seafood related industries, and the cost of maintaining public advisory services and monitoring programs for shellfish toxins and water quality. The impact of HABs can potentially be mitigated by early warning of their development. In this regard the project ASIMUTH (Applied Simulations and Integrated Modelling for the Understanding of Toxic and Harmful algal blooms) was borne in order to develop short term HAB alert systems for Atlantic Europe. This was achieved using information on the most current marine conditions (weather, water characteristics, toxicity, harmful algal presence etc.) combined with high resolution local numerical predictions. This integrated, multidisciplinary, trans-boundary approach to the study of HABs developed during ASIMUTH led to a better understanding of the physical, chemical and ecological factors controlling these blooms, as well as their impact on human activities. The outcome was an appropriate alert system for an effective management of areas that are usually associated with HAB events and where these episodes may have a more significant negative impact on human activities. Specifically for the aquaculture industry, the information provided enabled farmers to adapt their working practices in time to prevent mortalities in finfish farms and/or manage their shellfish harvest more effectively. This paper summarises the modelling and alert developments generated by the ASIMUTH project.