Diversity and geographical distribution of resting stages of eukaryotic algae in the surface sediments from the southern Chinese coastline based on metabarcoding partial 18S rDNA sequences

Surface sediment samples were collected from sixteen sites of the southern Chinese coastline in this study. Diversity of eukaryotic microalgae was examined using high-throughput sequencing of 18S rDNA to understand the community structure and geological distribution of microalgal resting stages. A total of 218 operational taxonomic units (OTUs) were detected for eukaryotic algae, and only 75 OTUs (34.40%) were detected into species level. The algal communities were composed of sixty-four genera belonged to twelve classes of four phyla. Dinoflagellates were the most abundant and diversified group, which accounted for the average of 56.26% and 53.70% DNA reads and OTUs, respectively. Dinoflagellates were dominated by Protoperidinium, Euduboscquella, Amylax, and Paragymnodinium. Chaetoceros, Thalassiosira, and Skeletonema were abundant in diatoms, while Pedospumella and Paraphysomonas in Chrysophyceae were the most abundant genera due to their massive occurrence in some particular sites. The high abundance of Protoperidinium sequences suggested the high nutrient levels in the southern Chinese coastline. Nineteen of the detected OTUs were assigned to harmful and/or bloom-forming microalgae. The wide occurrence of the toxic dinoflagellate Azadinium poporum and high abundance of Alexandrium pacificum in some particular sites suggested the potential risk of human poisoning.     

2000—2018 年福建近岸海域赤潮分布特征

收集2000—2018 年福建近岸海域224 次赤潮事件资料,通过综合分析结果表明：2000—2018 年福建近岸海域赤潮发现数量和面积分别占全国的17.3%和6.1%。2015—2018 年相对于2000—2004、2005—2009、2010—2014 年赤潮年均发现数量和面积有明显下降。赤潮发现月份和空间特征明显,5—6 月为高发期;宁德、福州、平潭、厦门、泉州海域是赤潮高发区;4 个时间段比较宁德和厦门海域年均发现赤潮数量下降明显,平潭海域略微下降,泉州海域增加。由甲藻门生物引发的赤潮数量、面积和损失均最高,诱发赤潮的生物类群存在南北差异,有毒赤潮占总赤潮数量的14.3%。根据提出的赤潮等级划分标准,福建近岸海域以小型赤潮为主。建议在宁德至平潭近岸海域、泉州近岸海域加强赤潮立体化监测系统的建设,5—6 月为监测的关键时期。     

生物和非生物因子对东海南麂岛海域表层沉积物甲藻孢囊分布的影响

本文首次对东海南麂岛海域的甲藻孢囊群落进行了为期一年（2014-2015）的定量分析研究。在南麂岛近岸8个采样点中,鉴定并定量了6个种群,34种形态的甲藻孢囊,其中包括14%的潜在产毒物种。自养型孢囊占总孢囊数量的74%。通过与邻近海域的研究结果比较,南麂海域总孢囊数量（2-33个孢囊/毫升沉积物）相对较低。Scrippsiella trochoidea和Protoperidinium avellana分别是丰度最高的自养和异养型孢囊。我们采用多元统计方法评估了甲藻孢囊分布同非生物或生物变量之间的关系。在DCA排序图中,发现季节之间有明显的分化。尽管采样点之间的水动力条件有所不同,甲藻孢囊的空间分布差异并不显著。可溶性活性磷酸盐,氮磷比和米氏凯伦藻（Karenia mikimotoi）藻华是通过CCA确定的与表层沉积物孢囊分布相关的三个重要因素（P<0.05）,这表明该区域营养盐状况对甲藻孢囊分布影响较大。虽然本研究未能明确近年来南麂岛海域有害赤潮的源头,但对于进一步了解南麂岛的甲藻孢囊动态和潜在的毒素威胁具有重要的参考意义。     

獐子岛海域浮游甲藻及有毒微藻的年际变化研究

2011—2017年,每月一次,通过对獐子岛海域29个站位浮游甲藻的调查,探究浮游甲藻种群结构的年际变化特征。发现了浮游甲藻19属47种,其中原多甲藻属(Protoperidinium)种类最多为17种,鳍藻属(Dinophysis)和角藻属(Ceratium)各4种,裸甲藻属(Gymnodinium)和原甲藻属(Prorocentrum)各3种,膝沟藻属(Gonyaulax)和环沟藻属(Gyrodinium)各2种,原角藻属(Protoceratium)、夜光藻属(Noctiluca)和凯伦藻属(Karenia)等均为1种。浮游甲藻种类数呈逐年递增,季节上呈现夏季和秋季较多,春季次之,冬季最少。浮游甲藻密度变化区间为(2.376—339.323)×10~4/m~3,平均密度为65.479×10~4/m~3,亦呈现夏季和秋季较高,春季次之,冬季最低,但密度呈逐年递减,且不同站位间差异较大。调查期间,不同季节优势种类有相同性,如三角角藻(Ceratium tripos)、梭角藻(Ceratiumfusus)和亚历山大藻(Alexandriumsp.)为四季优势种,但亦有差异,如鳍藻(Dinophysisspp.)和夜光藻(Noctilucascintillans)为夏季和秋季优势种,网状原角藻(Protoceratium reticulatum)为冬季和春季优势种。优势种中有毒微藻呈逐年增多趋势,有毒的链状裸甲藻(Gymnodiniumcatenatum)、米氏凯伦藻(Kareniamikimotoi)和具尾鳍藻(Dinophysiscaudata)等非优势种在獐子岛海域首次发现。浮游甲藻群落的香农-威纳指数、丰富度指数、均匀度指数均为秋季夏季春季冬季,呈逐年递增趋势。近年来,獐子岛海域浮游生物群落甲藻化和有毒化趋势明显,可能与海水营养盐比例失衡、海水酸化、北黄海冷水团、双壳贝类大规模养殖等有关。     

MSCT在邻关节骨囊肿诊断中的应用价值

目的：探讨邻关节骨囊肿的MSCT表现,提高对该病的术前诊断能力。方法：回顾性分析经手术病理证实的32例邻关节骨囊肿的临床及CT薄层扫描、多平面重组（MPR）表现。男20例,女12例,平均年龄42岁。结果：32例均为单发病变,共32个病灶,其中股骨头8个,胫骨近端8个,距骨6个,胫骨远端3个,腕月骨3个,股骨远端、髋臼、肱骨近端和腕舟骨各1个。病灶均位于骨内邻近关节面,病灶大小介于0.8cm×1.2cm～2.5cm×2.9cm之间。单房型26例,CT表现为圆形、类圆形或不规则形囊样低密度区,边缘清晰,均有薄层完整硬化边,相邻关节间隙无明显改变;多房型6例,病灶内有粗细不等的骨性间隔。病灶CT值20～60Hu,3个病灶内见细小气体密度影。穿透型18例,表现为病灶通过邻关节面裂隙与关节腔相通或病灶与关节旁软组织腱鞘囊肿相连;特发型14例,表现为骨内单一病灶,骨外结构正常。结论：邻关节骨囊肿有其特殊发病部位,CT表现典型,结合发病年龄和临床症状,可以作出正确的术前诊断。     

Geographical distribution of red and green Noctiluca scintillans

The dinoflagellate Noctiluca scintillans is one of the most important and abundant red tide organisms and it is distributed world-wide. It occurs in two forms. Red Noctiluca is heterotrophic and fills the role of one of the microzooplankton grazers in the foodweb. In contrast, green Noctiluca contains a photosynthetic symbiont Pedinomonas noctilucae (a prasinophyte), but it also feeds on other plankton when the food supply is abundant. In this review, we document the global distribution of these two forms and include the first maps of their global distribution. Red Noctiluca occurs widely in the temperate to sub-tropical coastal regions of the world. It occurs over a wide temperature range of about 10°C to 25°C and at higher salinities (generally not in estuaries). It is particularly abundant in high productivity areas such as upwelling or eutrophic areas where diatoms dominate since they are its preferred food source. Green Noctiluca is much more restricted to a temperature range of 25°C-30°C and mainly occurs in tropical waters of Southeast Asia, Bay of Bengal (east coast of India), in the eastern, western and northern Arabian Sea, the Red Sea, and recently it has become very abundant in the Gulf of Oman. Red and green Noctiluca do overlap in their distribution in the eastern, northern and western Arabian Sea with a seasonal shift from green Noctiluca in the cooler winter convective mixing, higher productivity season, to red Noctiluca in the more oligotrophic warmer summer season.     

Historical deposits of Alexandrium catenella resting cysts in the sediments of Queen Charlotte Sound,New Zealand

In 2011, a large repository of resting cysts of the toxic dinoflagellate Alexandrium catenella was discovered in the sediments of the Onapua/Opua inlet located off Tory Channel, Queen Charlotte Sound. The inlet is a potential source of infection for other areas, such as the major mussel-growing areas of Port Underwood and Pelorus Sound. This study aimed to establish whether the dinoflagellate was a new arrival in the Sounds or had existed unnoticed in this isolated embayment for some time. Alexandrium catenella cysts were identified to a depth of 20–21?cm within the sediment cores, corresponding to a date estimated by radioisotope (²¹⁰Pb and ¹³⁷Cs) and Pinus radiata pollen distribution to at least the mid 1970s. Over this time span, resident populations of A. catenella have not become established beyond the confines of Queen Charlotte Sound, suggesting it does not pose an imminent threat of doing so unless increasingly intense and prolonged blooms result in more widespread cyst dispersal.     

First record of Ostreopsis cfr. ovata on macroalgae in the Northern Adriatic Sea

Ostreopsis ovata is an epiphytic potentially toxic dinoflagellate. It has a world-wide distribution, normally associated with other epiphytic or benthic dinoflagellates. In tropical seas O. ovata is often associated with the genera Gambierdiscus, Coolia and Prorocentrum, causing cinguatera fish poisoning. Recently, Ostreopsis spp. blooms in the Tyrrhenian and southern Adriatic Sea have been related to human health problems, such as breathing and skin irritation. Here we report the first record of Ostreopsis cfr. ovata in the Northern Adriatic Sea. O. cfr. ovata was isolated from macroalgae in two areas, the Gulf of Trieste (Italy) and close to Rovinj (Croatia). The microalga was identified by scanning electron microscopy and by fluorescence light microscopy. Size range and thecal pore structure were similar to those described for O. cfr. ovata in previous studies. Ostreopsis cfr. ovata was present on all the macroalgae collected, particularly browns and reds. The microalgal association on macroalgae was mostly composed of Ostreopsis sp., Coolia monotis and Coscinodiscus sp.     

Zooplankton associations off otago peninsula,south‐eastern New Zealand,related to different water masses

Distinctly different water masses are to be found near the sea surface within 40 km of the coast off Otago Peninsula, south‐eastern New Zealand (45° 50’ S, 170° 45’ E). Although the hydrological regime is complex in this area, the three water masses have a stable relationship to one another: neritic water close to shore, then modified Subtropical Water, and Subantarctic Water off shore. Quantitative zooplankton samples from the upper 150 m were taken from a four‐station, 50‐km latitudinal transect at monthly intervals over 15 months, October 1966‐December 1967. Data were analysed by group‐average sorting methods into a hierarchical classification of 37 components, identified to species where practicable. Each species group was clearly associated with particular stations and from this hydrological affinities were deduced. The classification recognised a primary division between “neritic” and “oceanic” groups of zooplankton, each of which contained further subdivisions. “Neritic” zooplankton contained “coastal” and “shelf” subgroups; “oceanic” plankton contained “transitional” and “subantarctic” subgroups. Zooplankton from Otago waters had hydrological affinities which were consistent with their wider distributions. Presence of subtropical zooplankton in Otago waters helps to resolve confusing differences between various interpretations of surface circulation in the southern Tasman Sea.     

Palynomorph and palynofacies indications of age, depositional environments and source potential for hydrocarbons: Lower Cretaceous Zubair Formation, southern Iraq

Assemblages of miospores and dinoflagellate cysts encounterd in core samples three boreholes drilled in southern Iraq an Aptian-mid Albian age-range for the Zubair Formation, the largest oil reservoir in southern Iraq and neighbouring Kuwait. Four types of palynofacies have been identified, and are interpreted to indicate delta top swamp and marsh, delta front, prodelta and marine platform environments respectively. Amorphous matter comprises more than 50% of the organic component of some of the palynofacies in the upper part of the Zubair Formation. The rocks with which they are associated are highly rated as a potential source of liquid hydrocarbons. Those deposits yielding less than this (down to 12%) are considered to have moderate potential.