The COPAS’08 expedition to the Patagonian Shelf: Physical and environmental conditions during the 2008 coccolithophore bloom     

Stuart C. Painter  Alex J. Poulton  John T. Allen  Rosalind Pidcock  William M. Balch 《Continental Shelf Research》2010

Here we present observations of the hydrography of the Patagonian Shelf, shelf break and offshore waters, with reference to the environmental conditions present during the period of peak coccolithophore abundance. Analysis of a hydrographic dataset collected in December 2008 (austral spring/summer), as part of the Coccolithophores of the Patagonian Shelf (COPAS) research cruise, identified 5 distinct surface water masses in the region between 37°S and 55°S. These water masses, identified through salinity gradients, displayed varying mixed layer depths, macronutrient inventories and chlorophyll-a fluorescence. Subantarctic Shelf Water (SSW), located to the north of the Falkland Islands and extending north along the shelf break, was also host to a large coccolithophore bloom. The similarities between the distribution of calcite, as seen in remote sensing data, and SSW indicate that the coccolithophore bloom encountered conditions conducive to bloom development within this water mass. Analysis of chemical and environmental data also collected during the COPAS cruise revealed that many of the commonly cited conditions for coccolithophore bloom development were present within SSW (e.g. low N:P ratio, high N:Si ratio, shallow mixed layer depth). In the other water masses present on the Patagonian Shelf greater variability in these same parameters may explain the more diffuse concentration of calcite, and the smaller size of possible coccolithophore blooms. The distribution of SSW is strongly influenced by the latitudinal variation in shelf break frontal width, which varies from 20 to 200 km, and consequently strong hydrographic controls underlie the position of the coccolithophore bloom during austral summer.  相似文献   

Horizontal distribution and transport processes of bloom-forming Microcystis in a large shallow lake (Taihu, China)   总被引：1，自引：0，他引：1  

Xiaodong Wu  Fanxiang Kong  Yuwei Chen  Longjiang Zhang  Min Zhang  Peng Xing 《Limnologica》2010,40(1):8-15

The horizontal distribution of bloom-forming Microcystis in a specific lake area and the transport of Microcystis by wind-driven lake currents between Meiliang Bay and the open water of Taihu Lake were measured during continuous field observations from August 21 to 25, 2006. During the observations, the horizontal distributions of Microcystis, represented by Chlorophyll a, showed a clear concentration toward downwind lake areas. According to the lake currents and the Chl a concentrations on the boundary line between the Meiliang Bay and the open water, the transported Chl a was less than 2% of the total weight of Chl a in Meiliang Bay on August 22, 24 and 25. The results suggest that the horizontal distribution of the bloom-forming Microcystis was strongly affected by the wind conditions, and the wind-driven Microcystis accumulation was mainly determined by surface drift; the transport of Microcystis by lake currents was much less important in this large, shallow lake.  相似文献   

水母灾害的形成机理、监测预测及防控技术研究进展   总被引：5，自引：0，他引：5  

张芳  李超伦  孙松  魏皓  王彦涛 《海洋与湖沼》2017,48(6):1187-1195

受人类活动和全球变化双重压力的影响,近年来我国近海水母呈现增多的趋势,局部海域水母灾害连年发生,对近海核电站等重大设施安全运行、海洋经济可持续发展和海洋生态环境安全造成严重威胁。我们不仅亟需在科学上阐明我国近海水母灾害发生的重要过程和机制,而且在技术上亟需研发水母灾害监测预警系统和防灾减灾技术体系,以提升我国海洋水母灾害应对能力和海洋环境安全保障能力。本文在查阅文献资料、国际交流与合作、课题组的研究成果的基础上,综述国内外水母灾害的形成机理、水母灾害监测及防控技术的研究进展,分析各种水母监测技术,防控技术的局限性以及在特定海域成功应用的原因,展望今后我国水母灾害的监测技术及防控策略。  相似文献   

Metabolic changes in Phaeocystis poucheti (Hariot) Lagerheim during the spring bloom in Belgian coastal waters     

Christiane Lancelot 《Estuarine, Coastal and Shelf Science》1984,18(5):593-600

Incorporation of ¹⁴C-bicarbonate into the major intracellular end-products of photosynthesis (protein, polysaccharide, lipid) and two classes of exoproducts (oligomers and polymers) was measured in Belgian coastal waters at different stages of the spring phytoplankton bloom, entirely dominated by the alga Phaeocystis poucheti. It was shown that intracellular protein synthesis contributed 20–42% of the total intracellular ¹⁴C fixed and was positively correlated with the inorganic nitrogen content of the surrounding medium. The decrease of protein synthesis following nitrogen depletion is balanced by an increase of intracellular polysaccharide synthesis, which varies from 22 to 42% of the intracellular ¹⁴C fixed, and by an increase in extracellular release of high molecular weight material (18–60% of total ¹⁴C fixed) which forms a mucous envelope where cells are embedded. Lipid synthesis is not correlated with the ambient inorganic nitrogen content and represents a rather constant proportion (about 20%) of the intracellular ¹⁴C fixed.  相似文献   

Identification of coccolithophore blooms in the SE Atlantic Ocean off Namibia by satellites and in-situ methods     

H. Siegel  T. Ohde  M. Gerth  G. Lavik  T. Leipe 《Continental Shelf Research》2007

Sporadic occurrences of milky turquoise waters visible in true colour satellite imagery in the Benguela upwelling system off Namibia are characterized by high reflectances due to enhanced scattering properties. Previous opinion was that the features are due to increased reflectances by elemental sulphur (S⁰) resulting from upwelling or eruptions of hydrogen sulphide-enriched waters.  相似文献   

Two drifting paths of Sargassum bloom in the Yellow Sea and East China Sea during 2019-2020     

Chao Yuan  Jie Xiao  Xuelei Zhang  Mingzhu Fu  Zongling Wang 《海洋学报(英文版)》2022,41(6):78-87

The macroalgal blooms of floating brown algae Sargassum horneri are increasing in the Yellow Sea and East China Sea during the past few years. However, the annual pattern of Sargassum bloom is not well characterized. To study the developing pattern and explore the impacts from hydro-meteorologic environment, high resolution satellite imageries were used to monitor the distribution, coverage and drifting of the pelagic Sargassum rafts in the Yellow Sea and East China Sea from September 2019 to Au...  相似文献   

2019年南海北部近海水母暴发原因种的分子鉴定     

杜崇  贺君  孙婷婷  王雷  王方晗  董志军 《热带海洋学报》2022,41(2):142-148

我国水母暴发主要发生在黄渤海和东海海域, 在南海海域较为少见。文章对2019年5月海南海口、文昌和广东茂名等南海北部多处海域的水母暴发原因种进行了形态学观察和分子鉴定。形态学观察结果显示, 海口与文昌附近海域的暴发水母为同一种水母, 其伞部为半球形, 生殖下穴呈梨形突起, 口腕布满丝状物并在末端有1条鞭状附属物, 与鞭腕水母(Acromitus flagellatus)形态相似; 而茂名附近海域暴发水母区别于海口和文昌, 该水母伞部呈较平的半球形, 生殖下穴乳状突起, 口腕无丝状物, 与端棍水母(Catostylus townsendi)形态相似。基于线粒体核糖体大亚基基因(16S rRNA)序列比对, 海口和文昌附近海域暴发水母与东太平洋鞭腕水母相似性为97.5%和97.7%, 茂名附近海域暴发水母与马六甲海峡端棍水母相似性为93.5%。基于线粒体COI基因和16S rRNA基因构建的系统发育树结果表明, 海口和文昌附近海域水母为同一种水母, 与鞭腕水母聚在一支, 而茂名附近海域水母与端棍水母亲缘关系近。结合形态学观察和分子系统数据认为, 海口和文昌附近海域暴发水母为鞭腕水母(Acromitus flagellatus), 茂名附近海域暴发水母为端棍水母(Catostylus sp.)。  相似文献   

深圳大鹏湾一次球形棕囊藻藻华的发生过程及成因分析     

刘悦  李丽  翟晓辉  周娟  叶鹏浩  黄盛东 《热带海洋学报》2022,41(3):164-171

2021年1月下旬深圳大鹏湾沿岸海域发生球形棕囊藻(Phaeocystis globosa)藻华。为了探究球形棕囊藻藻华发生动态特征及其影响因素, 于1月20日至2月1日系统调查分析了藻华发生过程中浮游植物优势种演替、球形棕囊藻囊体数量、营养盐水平以及其他环境因素的变化。结果表明: 1月20日, 中肋骨条藻(Skeletonema costatum)为绝对优势种, 1月21日球形棕囊藻囊体开始出现, 1月25日囊体数量达到最高, 达69colonies·L^-1; 1月27日红色赤潮藻(Akashiwo sanguinea)藻华出现, 随后球形棕囊藻藻华逐渐消退。灰关联分析显示, 铵盐和硝酸盐是影响球形棕囊藻囊体丰度的最主要因素。水体扰动和球形棕囊藻在磷限制条件下的竞争优势也可能有利于球形棕囊藻藻华的发生。红色赤潮藻藻华可能是球形棕囊藻藻华消退的主要原因。球形棕囊藻藻华的发生和消亡是各种理化因素和生物因素共同作用的结果。  相似文献   

Impact of open-ocean convection on nutrients,phytoplankton biomass and activity     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

We describe the impact of an open-ocean convection event on nutrient budgets, carbon budget, elemental stoichiometry, phytoplankton biomass and activity in the Northwestern Mediterranean Sea (NWM). In the convective episode examined here we estimated an input of nutrients to the surface layer of 7.0, 8.0 and 0.4×10⁸ mol of silicate, nitrate and phosphate, respectively. These quantities correspond to the annual nutrient input by river discharges and atmospheric depositions in the Gulf of Lion. Such nutrient input is sufficient to sustain new primary production from 46 to 63 g C m⁻² y⁻¹, which is the same order of magnitude found in the NWM open waters. Our results together with satellite data analysis, propose new scenarios that explain the origin of the spring phytoplankton bloom occurring in NWM.  相似文献   

水母暴发研究所面临的挑战   总被引：7，自引：0，他引：7  

孙松 《地球科学进展》2012,27(3):257-261

在过去的10多年中,全球海洋中的水母数量都有所增加,在一些局部区域出现了水母种群暴发的现象,主要是在近海、特别是一些重要的渔场和高生产力区。水母暴发已经形成重要的生态灾害,对沿海工业、海洋渔业和滨海旅游业等造成严重危害。水母暴发的原因、生态危害、如何应对等是一个世界性难题,引起全球沿海国家的重视,也是国际海洋生态系统研究领域的焦点问题之一。由于水母特殊的生物学和生态学特性,水母暴发的研究面临众多的困难和挑战。水母的暴发与全球气候变化、海洋渔业活动、富营养化、海岸带工程等密切相关,水母暴发现象是海洋生态系统演变的一种具体体现,通过对水母暴发机理的研究,将会加深对在全球变化和人类活动共同作用下海洋生态系统演变机理和变化趋势的了解。  相似文献