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Large scale northward expansion of warm water species Skeletonema tropicum (Bacillariophyceae) in China seas 总被引：2，自引：0，他引：2
Skeletonema tropicum is regarded as a species with an affinity to warm waters and it has never been reported in seas where temperatures drop below 11°C in winter. Previous studies in China reported that S. tropicum was restricted to subtropical and warm temperate seas (East and South China Seas), but the species was recently found during August cruises of 2009 and 2010 in Jiaozhou Bay, Yellow Sea, located several hundred kilometers to the north. Here, winter water temperatures often drop below 5°C. Identification of S. tropicum was confirmed under light and scanning electronic microscopes and maximum cell abundance in Jiaozhou Bay was estimated as 1.73×10 4 cell/L. This record of S. tropicum in Jiaozhou Bay represents a significant northward expansion in the geographic range of the species. Ship ballast water was identified as a possible carrier of S. tropicum from southern places along Chinese coastline, and in addition, thermal pollution from local power stations and seawater desalination plants may provide suitable conditions for species over-wintering. 相似文献
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海洋沉积物中残留的硅壳、甲藻孢囊、类脂类化合物及生物硅等生态参数被广泛应用于反演和指示海洋古环境特征.本研究通过测定烟台四十里湾表层沉积物中的硅藻化石、甲藻孢囊、菜籽甾醇、甲藻甾醇及生物硅5种生态参数,比较不同生态参数的相关性及它们在反演海洋环境中的功能差异,建立了多参数综合应用的研究方法.研究发现,沉积物中的硅壳丰度与菜籽甾醇含量及生物硅含量存在明显正相关关系(P＜0.05),菜籽甾醇含量与生物硅含量可以较好的佐证与提高沉积物中硅壳对硅藻生物量指示的准确性;甲藻孢囊与甲藻甾醇含量相关性不明显(P＞0.05),相较而言,甲藻甾醇可以更准确的反演甲藻的生物量.因此,生物与化学参数的结合应用不仅可以提高生物量指示的精确性,而且有助于从物种组成角度更好的了解藻类对环境变化的响应特征. 相似文献
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2010 年4 月-2011 年3月对烟台近海（四十里湾和套子湾） 浮游植物群落结构时空变化特征展开了为期1年的双月
调查。在28 个站位的调查研究中,共发现浮游植物78 属187 种,其中硅藻50 属103 种,甲藻21 属73 种,褐胞藻5属7
种,绿藻1属3种,未定类1种。硅藻在数量与物种组成上为主要类群,分别占浮游植物总量的97.3 %与55.3 %,其次为甲
藻。浮游植物细胞丰度、多样性指数（H忆） 和均匀度指数（J） 呈现明显的季节特征：细胞丰度周年变动范围为0.6伊104~
156.7伊104 cells/L,最高峰出现在夏季（8 月）,次高峰出现在春季（3,4 月）;多样性指数（H忆）的周年变动范围是1.23~
2.55,均匀度指数（J）的周年变动范围是0.28~0.68,两者在夏初（6 月） 和秋季（10 月） 较高。浮游植物优势种在夏季以
硅藻-甲藻-褐胞藻联合为主,其余调查季节主要以硅藻为主。应用聚类分析分析了6个航次浮游植物群落结构的平面分布格
局。四十里湾和套子湾细胞丰度在整个调查期间无显著差异,而在秋季（10 月） 和冬季（12 月） 存在显著差异。春初（3
月）,四十里湾与套子湾浮游植物群落结构差异显著,其他调查季节两湾浮游植物并无显著差异。 相似文献
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我国典型潮间带底栖硅藻群落空间分布特征 总被引：2，自引：0，他引：2
底栖硅藻是河口、泥质海滩生态系统的重要生物类群,其数量与分布变化直接或间接地影响到多种海洋生物的饵料供给、海鸟的生存与迁徙。通过对我国从南到北14个典型潮间带表层沉积物中底栖硅藻的分析,共鉴定出硅藻153种,其物种多样性（Shannon-Weaver 指数范围:1.61~4.39）与生物量（范围:0.09×103 ~ 10×103个/g,干质量）在空间上存在显著差异;聚类分析与相似性分析检验（r=0.738,P=0.1%< 0.01）表明,14个调查区域的硅藻群落在空间上可分为4个大的组合,分别对应着渤、黄、东、南海4个区域,吻合了我国近海浮游植物的地理分布特征。与环境因素的相关性分析表明,底栖硅藻群落的物种多样性与生物量受沉积物类型与盐度的影响显著,泥质区域更有利于硅藻的保存,而生物多样性在泥砂质低盐区域相对较高。此外,底栖硅藻生物量与表层沉积物中TOC含量表现出显著正相关性;δ13C数值的空间变化范围为-25‰~-20‰,指示了有机质陆海混合的特征,其中,涧河河口、黄河口、大沽河口、苏北浅滩区域,δ13C数值明显偏正,表明底栖硅藻可能是这些区域沉积物中有机碳的重要贡献者。 相似文献
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2012年春季渤海中部及邻近海域叶绿素a与环境因子的分布特征 总被引：3，自引：1，他引：2
分析了2012年春季渤海中部及其邻近海域32个站点叶绿素a和环境因子的空间分布特征及其相互关系。结果发现:渤海中部靠近黄河口邻近水域相对于其他水域,呈现出相对较高的水温和较低的盐度,这与黄河淡水输入以及近岸水深相对较浅有密切关系。营养盐浓度在空间分布上表现为黄河口附近海域较高,在垂直分布上表现为中、底层高于表层,显示出黄河水输入与沉积物营养盐再释放的影响;此外,营养盐浓度与结构显示,渤海海域存在明显的磷和硅限制,磷限制尤其严重。叶绿素a浓度的空间分布显示,表层叶绿素a浓度的高值区出现在渤海湾湾口处,而中层与底层的叶绿素a浓度高值区出现在渤海中部。主成分分析结果表明,磷酸盐和温度是影响表层叶绿素a浓度的重要因素,而中、底层叶绿素a浓度主要受磷酸盐的影响。 相似文献
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The spatial distribution of siliceous microfossils (diatoms and silicoflagellates) in the surface sediments was mapped at 113 sites in the Yellow Sea and sea areas adjacent to the Changjiang (Yangtze) River, China. In total, 267 diatom taxa and two silicoflagellate species were identified from the sediments. The spatial variations in abundance and diversity were classified into three distinct geographic patterns using Q mode clustering: a south-north geographic pattern, a coastal-offshore pattern and a unique pattern in the Changjiang River mouth. The south-north geographic pattern was related to the spatial variations in sea temperature. Coscinodiscus oculatus, a warm-water species, indicated these variations by a gradual decrease in abundance from the south to the north. The coastal-offshore pattern was in response to the spatial variations in salinity. Cyclotella stylorum, Actinocyclus ehrenbergii and Dictyocha messanensis, the dominant brackish species in coastal waters, significantly decreased at the isobaths of approximately 30 m, where the salinity was higher than 31. Paralia sulcata and Podosira stelliger indicated the impact of the Yellow Sea Warm Current in the central Yellow Sea. The unique pattern in the Changjiang River mouth showed the highest species diversity but lower abundance, apparently because: freshwater input can significantly increase the proportion of brackish species; nutrients can supply the growth of phytoplankton; and high sedimentation rates can dilute the microfossil abundance in the sediments. Our results show that an integration of environmental factors (e.g., nutrient levels, sedimentation rate, sea temperature, salinity and water depth) determined the spatial characteristics of the siliceous microfossils in the surface sediments. 相似文献
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