渤海浮游植物群落结构时空分布及其影响因素

浮游植物群落结构的时空变化对生物地球化学循环、全球气候及渔业资源具有重要的影响.本文采用ROMS-CoSiNE高分辨率数值模拟结果,分析了渤海浮游植物生物量和群落结构的时空分布特征,讨论了浮游植物群落结构时空差异的主要影响因素.结果表明,渤海表层叶绿素浓度和甲硅藻比在冬季最低、夏季最高.叶绿素浓度呈条带状分布,甲硅藻比...     

大亚湾浮游植物粒级结构和种类组成对淡澳河河口水加富的响应

人类活动引起的营养物质输入导致大亚湾出现海水富营养化、赤潮频发和生物多样性下降等生态问题。为探究陆源输入影响下大亚湾湾顶淡澳河输入对湾内浮游植物粒级结构和种类组成的影响, 2016年10月在大亚湾进行了原位观测和培养试验。原位观测结果显示, 淡澳河口的总溶解态氮、磷浓度分别达到85.3μmol·L^-1和1.5μmol·L^-1。加富培养试验结果表明, 淡澳河河口水加富对总叶绿素a (Chl a)和总浮游植物丰度有显著促进作用, 并导致浮游植物粒级结构由小粒级Chl a (0.7~20μm)占主导; 浮游植物丰度中甲藻比例升高, 主要种类为锥状斯氏藻(Scrippsiella trochoidea)和原甲藻(Prorocentrum spp.)。同样, 尿素加富也促进了浮游植物群落中小粒级Chl a和甲藻的比例增加, 且主要甲藻种类与河口水加富结果一致。无机氮、磷同时加富促进了总Chl a和浮游植物总丰度增加, 而对浮游植物粒级结构和甲藻丰度则没有明显影响。对照河口水和氮、磷营养盐加富试验结果, 说明河口水携带的溶解性有机氮源可能是导致大亚湾浮游植物群落小型化, 促进甲藻生长的关键营养盐形态, 其携带的无机氮、磷同时促进总浮游植物丰度增加。本研究结果表明有机形态营养组分对大亚湾富营养化和有害藻华可能产生重要影响。     

基于网络药理学探讨滋补精血、温肾暖宫药物治疗卵巢功能异常疾病的作用机制

目的：基于网络药理学探讨滋补精血、温肾暖宫中药治疗卵巢功能异常疾病的作用机制。方法：采用TCMSP平台获取具有滋补精血、温肾暖宫作用的桑椹、覆盆子、小茴香的活性成分和靶点;网络药理学方法涉及“药物-成分-靶点”网络图的构建和靶点预测。运用京都基因与基因组百科全书（KEGG）数据库确定桑椹、覆盆子、小茴香与卵巢功能异常疾病集群网络的重要信号通路。采用分子对接软件对主要活性成分与核心靶点蛋白进行计算机模拟对接,预测主要成分与核心靶点的结合度。结果：筛选出欧前胡素、β-谷甾醇、槲皮素等10个有效成分,对应于桑椹、覆盆子、小茴香的196个靶点。此外,549个基因与卵巢功能异常疾病密切相关,其中87个与桑椹、覆盆子、小茴香的靶点重叠,被认为与治疗相关。KEGG通路富集分析显示桑椹、覆盆子、小茴香主要作用于卵巢功能异常疾病相关的炎症、卵巢类固醇生成及生长激素的合成分泌和作用等信号通路。分子对接结果显示主要活性成分欧前胡素、β-谷甾醇、槲皮素与靶点均能自发结合。结论：具有滋补精血、温肾暖宫作用的桑椹、覆盆子、小茴香通过多组分、多靶点和多途径协同治疗卵巢功能异常疾病,为后续进一步研究桑椹、覆盆子、小茴香的活性成分及作用机制提供了依据。     

河北抚宁海湾扇贝养殖区浮游植物与水质因子的相关研究

为研究抚宁海湾扇贝养殖区浮游植物变化特征,探讨水质因子对浮游植物的影响,2020年5月—11月,每月测定该海域的主要水质因子,统计浮游植物。结果表明:共鉴定浮游植物69种,优势种33种;浮游植物密度(8.3~267.9)×10⁴cell/L,5月份最高;生物多样性指数为0.458~3.747,均匀度指数0.099~0.796,丰富度指数0.933~4.755。海水水温范围11.8~26.8℃,盐度28.8~34.0,活性硅酸盐(SiO₃^2–-Si)含量0.025~0.627mg/L,硝酸盐氮(NO₃^–-N)浓度0.057~0.284mg/L,均呈“上升-下降”趋势;pH范围为7.867~8.190,化学需氧量(COD)为0.260~1.415mg/L,活性磷酸盐(PO₄^3–-P)0.003~0.006mg/L,变化趋势为“下降—上升”;对优势种与水质因子的分析表明,影响该海域浮游植物变化的主要环境因子为活性硅酸盐、盐度、活性磷酸盐和硝酸盐氮;裸藻门与活性磷酸盐、盐度呈正相关,与活性硅酸盐、硝酸盐氮呈负相关;甲藻门与活性硅酸盐呈正相关,与活性磷酸盐、硝酸盐氮呈负相关;隐藻门与活性硅酸盐、盐度成正相关,与硝酸盐氮呈负相关。     

Spatial patterns of phytoplankton communities in an International Seabed Authority licensed area (COMRA,Clarion-Clipperton Zone) in relation to upper ocean biogeochemistry

The Clarion-Clipperton Zone (CCZ) hosts one of the largest known oceanic nodule fields worldwide and is regulated by the International Seabed Authority. A baseline assessment of diversity and distribution patterns is essential for reliable predictions of disturbed ecosystem response scenarios for sustained commercial activities in the future. In the present study, the spatial patterns and diversity of phytoplankton communities were analyzed along with upper ocean biogeochemistry, in the licensed China Ocean Mineral Resources R&D Association (COMRA) contract area and the surrounding western CCZ between August 21 and October 8, 2017. Results indicated this was a typical low-nutrient low-chlorophyll a (Chl a) environment, characterized by low levels of phytoplankton abundance and diversity. In total 112 species belonging to 4 phyla were recorded (>10 μm), with species counts including 82 diatoms, 27 dinoflagellates, 1 cyanobacteria and 2 chrysophyte. Dominant taxa in successive order of descending abundance and occurrence included Nizschia marina, Cyclotella stylorum, Dactyliosolen mediterraneus, Rhizosolenia setigera, Pseudo-nitzschia delicatissima, Thalassiothrix frauenfeldii, Synedra sp., Chaetoceros simplex and Pseudo-nitzschia circumpora. The depth-averaged abundance and Chl a concentrations were (265±233) cells/L and (0.27±0.30) μg/L, respectively. Diatoms accounted for 90.94% of the community with (241±223) cells/L, while dinoflagellates accounted for 5.67% and (15±13) cells/L. The distribution pattern exhibited the same trend as abundance, Chl a and species richness, showing subsurface maximum levels at around 100 m, with stations near 10°N having higher levels than in the north. Cluster analysis was performed in two assemblages, relating to geographic locations to the south and north of 12°N. The subsurface maximum of abundance, Chl a, species richness, dissolved oxygen and nitrite were generally corresponding to the presence of high salinity North Pacific Central Water at depths of 50?120 m. Higher availability of nitrate, phosphate and silicic acid in the subsurface may account for the shift in phytoplankton distribution, as shown by redundancy correspondence and spearman correlation analysis. Diel variation in an anchor station demonstrated prominent species succession without significant differences in oceanographic variables, among which diatoms succession resulted from the light limitation, while dinoflagellate diel variation mainly related to lateral transport of water masses. The observed patchiness in spatial phytoplankton distributional patterns was attributed to upper ocean environmental gradients in the CCZ. The baseline generated in this study could be analyzed using current conservation strategy programs associated with deep-sea mining.     

Institutional challenges for policy-making and fisheries advice to move to a full EAFM approach within the current governance structures for marine policies

The European Union is aiming to implement an Ecosystem Approach for the management of all human activities in the marine environment, hereunder the fisheries sector. Since the last reform of the Common Fisheries Policy in 2013, several analyses have highlighted the barriers and challenges to this aim. Despite the claim that much of the framework to support the implementation of an EAFM in Europe is in place, the findings point out to deterrent features within the governance system. Beyond the overall policy framework, this paper explores the implementation of the multiannual multispecies management plans as one of the real moves towards Ecosystem Approach to Fisheries Management. This is carried out on the basis of two case studies that address the design of multiannual multispecies management plans for the Baltic Sea and for the Atlantic Pelagic fisheries. The analyses strengthen with empirical evidences our understanding of the challenges ahead including, among others, an institutional gap between fisheries and environmental policy frameworks resulting in a limited integration of broader environmental concerns in one of the proposed plan and the standoff between decision-makers that delays the adoption and use of proposed management plans and creates frustration for the involved agencies.     

三门湾网采浮游植物季节变化及影响因素

于2015—2016年春(5月)、夏(8月)、秋(11月)和冬(1月)四个航次对三门湾18个站位进行拖网采集和理化因子测定,分析了三门湾浮游植物群落结构、优势种组成、时空分布和主要影响因素,并结合历史数据,分析了浮游植物群落结构的变化规律,探讨了其主要驱动因子。调查共检出浮游植物8门87属199种(含变种、变型和未定名种),其中硅藻51属149种,甲藻18属27种,绿藻、裸藻、隐藻、定鞭藻、金藻和蓝藻偶有检出。四季共检出优势种8属13种,其中琼氏圆筛藻(Coscinodiscus jonesianus)为全年优势种。浮游植物年均丰度为1632.04×10~4cell/m~3,其中春季最低(53.06×10~4cell/m~3),夏季最高(5548.91×10~4cell/m~3)。聚类和相似性分析结果表明,浮游植物群落季节变化和区域差异明显。典范对应分析表明,影响三门湾海域浮游植物群落的主要因子依次为温度、盐度、DIN和DSi。结合历史资料发现,三门湾浮游植物群落丰度总体呈增加趋势(排除20世纪80年代冬季赤潮影响),主要种类组成仍以硅、甲藻为主,赤潮藻及嗜氮性硅藻种类数及优势度均上升。此外,三门湾浮游植物由大型硅藻向链状硅藻演替。海域富营养化和水温上升可能是主要驱动因子。     

冬季南海北部海域微型浮游动物及其对浮游植物摄食压力研究

2009年1月在南海北部海域的5个站位,采用稀释法和显微分析技术研究了浮游植物生长率及微型浮游动物对浮游植物的摄食压力,同时测定了微型浮游动物的丰度及类群组成.结果表明:南海北部微型浮游动物类群主要以无壳纤毛虫为主,南海北部微型浮游动物类群细胞丰度为33～529个/dm3.南海北部浮游植物生长率为0.45～1.83 d-1,微型浮游动物摄食率为0.44～1.76 d-1,摄食压力占浮游植物现存量的42.6%～82.8%,占初级生产力的97.3%～225.1%.近岸区摄食压力比陆架区高,表明冬季南海近岸区微型浮游动物摄食能够有效的控制浮游植物的生长,而陆架区浮游植物生长率大于摄食率,浮游植物存在着现存量的积累,微型浮游动物并不能完全控制浮游植物的生长.     

Dividing the algal soup: is there niche separation between native bivalves (Echyridella menziesii) and non-native Daphnia pulex in New Zealand?

ABSTRACT

New Zealand's native freshwater mussels (kākahi, kāeo) are considered to be in decline, yet the mechanisms driving this are unclear. The widespread establishment of highly efficient filter-feeding, non-native Daphnia in New Zealand lakes may have led to competition for algae with kākahi. We conducted a controlled laboratory experiment to determine whether differences exist in algal resources utilised by kākahi and North American Daphnia pulex. Echyridella menziesii (adults and juveniles) and D. pulex were exposed to mixed algal samples for three hours to determine whether similar algal resources were removed by the grazers. Relative to controls, both adult and juvenile E. menziesii removed a broad range of algal taxa including diatoms, green algae and filamentous species, ranging in size from 33.6 to 348.0?μm. High densities of D. pulex were unable to cause depletion of these same algae species. Our results suggest niche overlap is limited between the two grazers; E. menziesii utilises larger particles than D. pulex.     

2011～2012年度大亚湾海域浮游植物群落的季节变化

于2011年12月至2012年11月采集了大亚湾海域9个站位表层水样, 对大亚湾海域的浮游植物群落结构进行了周年调查。本次调查共鉴定出浮游植物93种, 其中硅藻门40属55种, 甲藻14属33种。秋季浮游植物种类较为丰富, 春季和夏季较低。浮游植物细胞密度为41～396个/mL, 年平均值为72.5个/mL。浮游植物细胞密度夏季较高, 春季较低。硅藻是浮游植物优势类群, 年均占浮游植物总细胞密度的83.6%, 优势硅藻主要有拟菱形藻(Pseudo-nitzschia spp.)、丹麦细柱藻(Leptocylindrus danicus)、中肋骨条藻(Skeletonema costatum)等。甲藻细胞密度一般较低, 各季节甲藻的百分比含量为1.5%～32.6%, 春季血红哈卡藻(Akashiwo sanguinea)大量出现, 最大细胞密度高达82.3 个/mL。浮游植物种类多样性指数(H′)和均匀度(J)在冬季和秋季较高, 夏季较低; 远岸站点较高, 近岸站点较低。研究结果说明虽然大亚湾浮游植物群落结构仍以硅藻占据优势, 但甲藻种类与数量及百分比具有明显上升的趋势, 同时近岸海域的富营养化导致了浮游植物种类多样性的下降。