江阴港口外来船舶压载舱沉积物中甲藻包囊种类及组成

为了探究外来船舶压载舱沉积物中甲藻休眠包囊的种类组成及外来甲藻入侵风险, 本文根据包囊及其萌发细胞的形态特征辅以分子生物学信息对江阴港5艘外来船舶压载舱沉积物中的活体甲藻休眠包囊的种类进行鉴定和分析。共鉴定出甲藻休眠包囊29种(不含3种未鉴定种), 包括膝沟藻类、钙甲藻类、裸甲藻类、翼甲藻类以及原多甲藻类, 活体休眠包囊密度介于0.73-44.3 cysts/g DW。其中塔玛亚历山大藻复合种(Alexandrium tamarense species complex)、网状原角藻(Protoceratium reticulatum)、具刺膝沟藻(Gonyaulax spinifera)等有毒有害甲藻的包囊在取样的5艘船舶中均有发现。此外还发现了多种中国近海未报道的甲藻包囊种类, 其中一种经过分子手段确定为异常亚历山大藻(Alexandrium insuetum)包囊, 萌发和培养实验表明该种包囊能够在中国近海萌发并增殖, 有潜在的入侵风险和暴发赤潮的可能性。     

九龙江西陂库区沉积物甲藻孢囊的分布

孢囊在甲藻的生活史中发挥重要作用,福建省九龙江从2009年起,暴发多次拟多甲藻水华事件。采用显微镜观察和单细胞PCR技术,对九龙江西陂库区2012—2013年不同月份沉积物中的甲藻孢囊进行种属判定,并对甲藻孢囊的分布及其影响因素进行分析。结果表明,西陂库区沉积物中的甲藻孢囊主要为拟多甲藻属,约占80%,其次为裸甲藻属,发现了2009年水华的优势种佩式拟多甲藻(Peridiniopsis penardii)孢囊。库区沉积物中甲藻孢囊的丰度在(13.7±1.2)—(105.2±8.3)个/g干重之间。多元相关分析结果显示甲藻孢囊的丰度与含水率呈现显著正相关性(P0.05),反映了甲藻孢囊沿水流方向逐渐积累。本研究结果填补了国内水库甲藻孢囊鉴定和萌发的研究空白,为九龙江甲藻水华的防治提供科学参考。     

中国淡水多甲藻属研究

板片形态和排列格式是有壳甲藻的重要分类依据, 荧光染色法和扫描电镜在显示板片排列上具有独特优势。通过这两种方法, 并结合光学显微技术, 对我国淡水多甲藻属Peridinium 11种的形态结构和板片排列进行了描述, 其中6种为中国新记录, 它们是加顿多甲藻P. gatunense Nygaard、古氏多甲藻P. gutwinskii Woloszynska、拉氏多甲藻P. lomnickii Woloszynska、腭状多甲藻P. palatinum Lauterborn、线纹多甲藻P. striolatum Playfair和带多甲藻P. zonatum Playfair。     

中国淡水拟多甲藻属研究

拟多甲藻属Peridiniopsis Lemmermann是重要的淡水有壳甲藻,是形成淡水甲藻水华的主要类群之一。该属被定义为不具或仅有一块前间插板的多甲藻类群,其板片格式为3–5′,0–1a,6–7(8)″,5″′,2″″。迄今,全球范围内报道的拟多甲藻属约有20种。通过对所采集国内甲藻标本的整理和鉴定,描述了8种及1变种,并对其形态特征、板片排列、生境和分布进行了简述。其中有3个是中国新纪录,它们是柏林拟多甲藻P.berolinensis(Lemmermann)Bourrelly、波吉拟多甲藻P.borgei Lemmermann和柯维拟多甲藻P.kevei Grig-orszky et Vasas。     

蓝裸甲藻有性生殖的初步观察

早在1879年,Joseph就描述了Peridinium stygium的配子融合现象.之后的近八十年中,对甲藻生活史中是否存在有性生殖一直存在着争论.直至Von Stosch(1964)报道了Ceratium horridium和C. cornutum有性生殖核配的详细过程后,甲藻的有性生殖才得到公认.迄今,至少已在15属30种甲藻的生活史中观察到有性阶段.       

深圳湾表层沉积物中甲藻孢囊的垂直分布

采集了深圳湾3个采样点约20cm的表层沉积物样品,研究了甲藻孢囊的垂直分布。共分析鉴定出孢囊类型37种,其中5种为我国沿海未报道的新记录类型,原多甲藻类孢囊是该海域种类最丰富的孢囊类型。除上表层沉积物外,深圳湾甲藻孢囊密度较低,孢囊密度大多在500cysts／gDWt以下,总孢囊密度变化范围为83～4036cysts／gDWt之间。锥状斯氏藻是深圳湾甲藻孢囊的优势种类,上表层沉积物中该孢囊密度的急剧上升证实了2000年附近海域所发生的该藻赤潮。而裸甲藻类孢囊含量明显比南海其他海域高。孢囊的香农-威弗种类多样性指数为1．50～3．96之间,并且在非养殖区、离岸海域及较深层次沉积物中较高,而孢囊密度则呈相反的变化趋势。种类多样性的下降及孢囊密度的上升在一定程度上说明深圳湾污染的变化趋势,富营养化程度非养殖区大于养殖区,近岸海域大于离岸海域,并且近年来污染逐渐加剧。     

甲藻孢囊在长江口海域表层沉积物中的分布

为了了解长江口海域赤潮爆发潜势,于2002年4月至5月用采泥器采集了位于122°～123．5°E、29°～32°N之间12个站位的表层沉积物,分析沉积物中甲藻孢囊的分布．共分析鉴定出孢囊类型29种,其中自养型11种,异养型18种．每个站位的孢囊种类在10～21之间,孢囊密度为11．7～587孢囊·g-1干泥之间．远岸海域孢囊种类较为丰富,密度也较高．在调查区域内,孢囊密度及种类自西向东、自北向南逐渐增加．亚历山大藻孢囊分布广泛,最高密度为40．4孢囊·g-1干泥,其他赤潮种类的孢囊如链状裸甲藻、多边舌甲藻、锥状斯氏藻、科夫多沟藻和无纹多沟藻等都在长江口海域有分布．     

慢原甲藻——南海热带附生甲藻新记录

从海南陵水新村港分离出1株附生原甲藻,在光学显微镜和扫描电子显微镜下进行形态学特征分析,并结合核糖体18S rRNA基因序列分析,鉴定为慢原甲藻(Prorocentrum rhathymum),为国内首次报道.国内曾将该种与墨西哥原甲藻(Prorocentrum mexicanum)归为同种异名.     

河口近海桡足类休眠卵生态学研究进展

桡足类是水域生态系统的关键类群,在物质循环、能量流动和信息传递中起着重要作用.休眠卵是桡足类的重要生存策略,在抵抗不利环境、维持种群延续等方面起着重要作用.本文综述了河口近海桡足类休眠卵种类组成及其分布、休眠卵存活时间、休眠卵萌发率和沉积物中休眠卵丰度以及对水体的潜在补充量及其影响因素等.对河口近海桡足类休眠卵生态学研究提出了展望,以期为相关研究提供新的思路.     

锥状施克里普藻孢囊的多种形态特征

休眠孢囊是某些甲藻生活史的重要阶段, 它被认为是甲藻赤潮爆发的种源。通过观察我国沿海海域采集的锥状施克里普藻(Scrippsiella trochoidea (Stein) Loebl ich)休眠孢囊的类型以及形态特征, 并将实验条件下形成的休眠孢囊与海区沉积物中休眠孢囊的形态特征进行比较, 结果表明, 锥状施克里普藻细胞在20°C、12小时光照/12小时黑暗、f/2培养基和f/2-N培养基中分别培养至第14天和第8天, 可以观察到休眠孢囊的产生。培养30天后, 培养液中有大量休眠孢囊, 将藻液避光保存90天后, 观察到培养基中有4种类型的休眠孢囊产生: (1)球形到椭球形(长25-39 μm), 钙质外壁, 稀疏或密被钙质附属物(长1-4 μm); (2)球形(直径为29-35 μm), 钙质外壁, 附属物非钙质(长0.5-1.5 μm); (3) 球形到椭球形(长29-35 μm), 钙质, 表面光滑, 无附属物; (4) 球形(直径24-35 μm ), 有机外壁, 无附属物。第1种类型的孢囊最为常见, 分别占到2种培养条件下所得全部孢囊的77.70%和95.18%。从沉积物中所得的孢囊多属于第1种类型。分析了实验条件下形成不同类型休眠孢囊的原因和比例, 同时探讨了海区沉积物中形成多种孢囊形态特征的原因, 为锥状施克里普藻孢囊的生态研究提供了依据。     

Cyst formation,sedimentation, and preservation: Factors affecting dinoflagellate assemblages in recent sediments from trondheimsfjord,Norway

Plankton records and 25 samples of Recent sediment from Trondheimsfjord and the adjoining shelf were studied to investigate production, sedimentation, and preservation of cysts, as factors which influence the eventual composition of dinoflagellate cyst assembleges. All sediment samples were examined for dinoflagellate cysts using routine semiquantitative palynological procedures. In addition, fjord sediments were subjected to a limited sediment analysis, and, for three samples, results from preparations both with and without acid treatments were compared. For the first time, cyst assembleges from Recent sediments were directly compared with extensive plankton records from overlying waters. Results indicate that approximately 20% of the 55 locally recorded dinoflagellate species contribute cysts to bottom sediments. Once formed, cysts behave as fine silt particles in the sedimentary regime, increasing in abundance as the percentage abundance of finer sediment increases, usually with increased water depth. Cyst-forming species are almost entirely restricted to a few genera, particularly Gonyaulax and Peridinium, within the order Peridiniales. For some groups, reasonably good correspondence was found between percentage abundances of dinoflagellates in plankton and their cysts in sediment, though plankton records covering at least five years were required to establish this. Gonyaulax grindleyi Reinecke (Von Stosch 1969) appeared to be consistently overrepresented by cysts in sediment relative to available plankton evidence; possible explanations are suggested. At least 30% of the cyst species present, including most Peridinium species, were eliminated, or rendered unreliable for semiquantitative palynology, by application of routine palynological preparation treatments. Such cysts may provide useful, non-quantitative, palynological information from Recent and possibly Quaternary sediments, but their persistence would seem unlikely. Thus, factors of preservation probably further restrict the dinoflagellate fossil record. Cyst assemblages from Trondheimsfjord are comparable with those previously recorded from the northeastern coast of U.S.A., and from Scotland and northeastern England. Fjord assemblages are dominated by small, simple, spinose cysts which would be regarded as acritarchs if culture experiments had not proved that they are dinoflagellate cysts. Much potential biogeographic and palaeoenvironmental information was included within the less abundant species.Attention is drawn to the role which future culture experiments may be expected to play in helping to resolve taxonomic difficulties currently affecting dinoflagellate studies. Palynological significance of results from the present study is discussed especially with reference to recent work by Von Stosch which strongly suggests that cysts may be hypnozygotes formed routinely in sexual cycles of dinoflagellates.     

Plankton dynamics in the Mar Piccolo of Taranto: a pilot plan

Abstract

An integrated sampling of both active (cells in water column) and resting stages (cysts sinking to the bottom) of phytoplankton, was carried out on March 1996 in the Mar Piccolo of Taranto. At least 46 taxa were recognized in the water column. Cyst sinking rate was about 23,000 m^-2 d^-1. Out of 37 recognized morphotypes, mainly dinoflagellates, 18 were previously unrecorded from the area. The present sampling represents the preliminar test to outline an experimental design to an integrated study of plankton dynamics.     

Seasonal distribution of dinoflagellate resting cysts in surface sediments from Changjiang River Estuary

In order to understand the distribution of dinoflagellate cysts, surface sediments were collected from 15 stations in Changjiang River Estuary from 122°E to 123.5°E and from 29°N to 32°N in four cruises from May 2002 to February 2003. In the present study, 38 different cyst morphotypes representing 21 genera and 6 groups were identified, while 1 type was not identified into genus level. Species number and cell density of dinoflagellate cysts ranged from 10 to 25 species and from 12 to 587 per gram of dry weight, respectively. There were no obvious differences in cyst composition and density among seasons. However, the highest cyst species number and density were recorded in summer and winter, respectively. Cysts of heterotrophic dinoflagellates, which held 55.7% of the overall cyst density averagely, dominated cyst assemblages. Cyst density and species number increased from the west to the east, from the north to the south within the study area. Cysts of toxic dinoflagellates Alexandrium cat‐enella and Alexandrium tamarense complex distributed widely and were observed in almost all stations, with the maximum cell density of 81 per gram of dry weight.     

Anostracan cysts found in California salt lakes

The salt lakes of California are home to four genera and eight species of Anostraca. The cysts of most of these species are readily distinguished using a combination of cyst and geographic characters. Cyst identification is a valuable tool that can allow a look at fairy shrimp ecology when adults are not available. For example, fossil anostracan cysts from 500-year-old Mono Lake sediments show more character variation than currently exists in extant Artemia monica, indicating a greater diversity of Anostraca at that time. Continuing desertification, both natural and man-made, in the Mono Lake area over the last 500 years is associated with decreased diversity in the Mono Lake anostracan fauna.     

有害甲藻孢囊的分类鉴定研究进展

有害甲藻孢囊主要是指能产生毒素和(或)能引起有害藻华发生并对水生态系统产生各种危害效应的甲藻孢囊。我国沿海共记录了10属18种,占全球有害甲藻孢囊的3/4。这些有害甲藻孢囊广泛分布于我国沿海,会对水产养殖业造成严重的经济损失,甚至会威胁人类的身体健康。因此,有害甲藻孢囊的多样性及分布越来越受到人们的关注。对有害甲藻孢囊的准确判断不仅对研究其多样性及分布至关重要,而且有助于水产品的安全检验和有害藻华的早期预警。对有害甲藻孢囊的分类主要存在鉴定困难、鉴定不准确等问题。本文综述了有害甲藻孢囊的危害、中国沿海有害甲藻孢囊的种类和分布,以及有害甲藻孢囊的鉴定等3个方面的研究进展,并提出利用孢囊及营养细胞的形态学特征、分子生物学、毒理学等多学科研究手段准确鉴定有害甲藻孢囊的建议。     

Modem organic-walled dinoflagellate cysts in arctic marine environments and their (paleo-) environmental significance

The Arctic Ocean is one of the least known marine regions of the world. Because of its major influence on global climate and its hostile environmental conditions it is a fascinating area for paleoecological, paleoclimatic and paleoceanographic research. The composition of planktic microfossil assemblages, and both the trace-element and stable isotope compositions of hard parts, provide us with valuable information about the physical and biochemical parameters of surface waters in the high northern latitudes. Calcareous and biosiliceous microfossils that are traditionally used in Quaternary paleoenvironmental studies are of limited value in the Arctic Ocean because of their low abundances, low diversity and/or low preservation potential. The past several decades have seen considerable progress in our knowledge of the ecology and biogeography of dinoflagellates and their organic-walled cysts in the high northern latitudes, and these dinoflagellate cysts are now important proxies for reconstructing surface water conditions in the Quaternary. This arcticle gives an overview of the ecology of dinoflagellates and their cysts, the processes that transform the living communities into sediment communities, and the environmental gradients that may be reconstructed from fossil dinoflagellate cysts assemblages in the high northern latitudes.      

Dinoflagellate cysts from sediment traps deployed in the Bellingshausen,Weddell and Scotia seas,Antarctica

Dinoflagellate cysts have been recovered from six long-term (1–2 yr) sediment trap moorings deployed in the Bellingshausen, Weddell and Scotia seas, Antarctica. These traps, mostly moored near the sea bed to sample the nepheloid layer, were located both within and to the north of the maximum sea-ice limit. The numbers of cysts, together with the composition of the assemblages, reinforce the importance of the maximum sea-ice limit as a modern biogeographic boundary for the distribution of dinoflagellate cysts. Cysts derived from heterotrophic dinoflagellates make up the highest proportions within the assemblages recovered from the traps. One trap sampled the export production, revealing little difference in cyst flux over those sampling the nepheloid layer. Cyst flux appears to be highest in areas closest to the Antarctic Convergence, north of the maximum sea-ice limit, and to high nutrient availability. There are, however, differences between the sediment trap assemblages and those recovered from core-top samples at the same or nearby sites. These differences, in the greater number of cysts, and in the higher numbers of round, brown Protoperidinium cysts in the traps, may reflect annual differences in the primary productivity and/or cyst production in the area. In some areas the sediment record may preserve little information about local surface water productivity because of the activity of bottom water currents, for example those arising from the Antarctic Circumpolar Current.     

Biodiversity and Association of Dinoflagellates in Coral Reef Rubble,Carrie Bow Cay,Belize

The species diversity and distribution of benthic dinoflagellates are illustrated from the back reef sand habitats at Carrie Bow Cay. Sand appears an ideal environment for nurturing a variety of species. Sand supported blooms of toxic, nontoxic, and parasitic assemblages of dinoflagellates. Morphology of dinoflagellates is illustrated in SEM and LM pictures; including the life cycle of a parasitic dinoflagellate's vegetative stage, sporogenetic stages, and the morphology of the feeding organelle. The feeding organelle of the primary dinoflagellate cysts is a hold fast and a peduncle‐like infestation tube, a ‘sucker organelle’, that inserts itself into copepod eggs. The parasitic dinoflagellate continues feeding on crustacean eggs since it is the only food source during vegetative cell division within the cyst. This is the first observation of the presence of parasitic dinoflagellates in shallow coral reef water. The study attempts to provide new knowledge on dinoflagellate associations and morphology of sand‐welling species in the microscopic food web of shallow warm tropical waters. Even, sand‐inhabiting invertebrates are not exempt from parasitic dinoflagellates.     

Preservation of organic-walled dinoflagellate cysts in different oxygen regimes: a 10,000 year natural experiment

The occurrence of organic-walled dinoflagellate cysts in (fossil) sediments depends on several factors, including as the ecological preferences of the cyst-forming dinoflagellates, cyst production, transport and preservation. Although laboratory experiments have shown that several cyst species are sensitive to chemical treatment, no information about the selective preservation of dinoflagellate cyst species in natural environments has previously been presented. Here, we present data on the effects of oxygen availability in bottom sediments on a cyst assemblage from the ungraded Madeira Abyssal Plain f-turbidite of which only the upper layer has been oxidized. Based on differences in species composition between the oxidized and underlying, unoxidized layers of this turbidite, the influence of oxygen availability on the preservation of individual species has been estimated. Cyst species have been classified in ascending order of resistance to oxygen availability in sediments as: (1) highly sensitive (cysts formed by Protoperidinium species), (2) moderately sensitive (e.g. Spiniferites species), (3) moderately resistant (e.g. Impagidinium paradoxum and Nematosphaeropsis labyrinthus) and (4) resistant (e.g. Impagidinium aculeatum).