南黄海生物硅的时空变化     

张丹  鉴珊  孙军  冷晓云  张桂成 《海洋学报(英文版)》2019,38(12):101-110

Concentrations of biogenic silica(BSi) in the southern Yellow Sea were determined during four cruises(spring:April–May 2014; autumn: November 2014; summer: August–September 2015; winter: January 2016). Samples of BSi were measured using the double extraction method. Seasonal and spatial variations of BSi and the potential correlation between chlorophyll a(Chl a) content and BSi in four seasons were measured in this study. Significant spatial variability was observed in seawater BSi concentrations. The average concentration of BSi was highest in winter and lowest in spring. Furthermore, the relationships between concentrations of BSi and hydrological parameters were also discussed. There was a significant positive correlation between Chl a and BSi. The concentrations of BSi showed significant relationships with temperature and the concentrations of silicates, total inorganic nitrogen and total inorganic phosphorus, indicating that distribution of BSi was affected by temperature and nutrient level.  相似文献   

温度对海洋硅藻吸收或释放一氧化氮的影响     

王可可  田野  姜源庆  李培峰  刘春颖  杨桂朋 《海洋科学》2019,43(11):35-41

基于全球变暖的背景,研究了温度对三角褐指藻(Phaeodactylumtricornutum)、小新月菱形藻(Nitzschiaclosteriumf.minutissima)和中肋骨条藻(Skeletonemacostatum)生长的影响,并初步探讨了温度对海洋硅藻生长过程中吸收或释放一氧化氮(NO)的影响。培养温度分别为20℃和25℃。结果显示,温度升高,中肋骨条藻的比生长速率降低(P0.05),而对三角褐指藻和小新月菱形藻的生长没有明显影响。不同种类硅藻对高温的适应能力不同,且在不同生长阶段对NO呈现不同的吸收或释放规律。与20℃培养条件相比,25℃条件下三角褐指藻对NO的净吸收速率在指数生长期、生长平台期和衰亡期分别升高了40.2%、98.2%和16.0%;小新月菱形藻对NO的净吸收速率在生长的平台期升高了5.7倍;中肋骨条藻对NO的净释放速率在生长的平台期升高幅度最大,为11.5倍。结果表明全球变暖对不同种类的硅藻代谢NO的促进程度不同。  相似文献   

中国南海表层沉积硅藻的分布及其与环境关系探讨          下载免费PDF全文

孙美琴  蓝东兆  王遹其  薛蕾 《海洋科学进展》2014,32(4)

通过对中国南海62个站位表层沉积硅藻的分析,查明研究海区硅藻的种类组成及分布特点。共鉴定到硅藻56属的235个种(包括变种和变型),以热性外洋种为优势,伴有一定量的近岸广布种。总体上,南海硅藻丰度变化呈现从陆架向陆坡至海盆递增的趋势。根据表层沉积硅藻中具有指示意义的硅藻种的分布和生态变化,划分6个硅藻组合带,各组合分别反映不同的海洋环境,其分布主要受到海洋环流的影响,表现为黑潮暖流、印度洋暖水的入侵以及沿岸流对南海表层沉积硅藻分布的影响。与南海相邻海区硅藻种类比较结果表明,研究海区表层沉积硅藻种类组成与临近的菲律宾海域相似程度最大,其次是中国东海海域、太平洋东北部海域。  相似文献   

青莲岗遗址孢粉及硅藻记录的古环境变化历史     

尹建吉  胡竹君  吴小爽  林留根  甘恢元  张驰  萧家仪 《第四纪研究》2019,(1):183-196

废黄河南岸的青莲岗遗址是江淮东部重要的新石器遗址,了解其古环境背景变化对于认识该遗址的发展具有重要意义。通过对青莲岗遗址考古地层的AMS 14C年代、孢粉和硅藻的综合分析,探讨了海水对该遗址的影响及水环境的变化。研究结果表明,生土层堆积后期(5.9 cal.kaB.P.以前),孢粉中莎草科占绝对优势,伴生蒿和藜科,硅藻组合中半咸水属种为优势种,海水种破碎壳体较多,可能为水动力较强的滨海盐沼环境。新石器文化层堆积期(5.9~4.8 cal.ka B.P.),硅藻属种中半咸水种减少,淡水底栖附生种为主要优势种,海水种硅藻破碎壳体的个数快速下降,表明此时环境逐渐稳定,海水或半咸水的影响减弱,适宜新石器先民的生产和生活。孢粉中水生、湿生草本和大型禾本科花粉增加,表明浅水水域面积增大,稻作农业开始出现。历史和近代时期(4.8 cal.ka B.P.以来),大型禾本科花粉急剧降低,表明稻作活动基本不存在。此时,硅藻中海水种和海水种破碎壳体有所增加,表明受到海水一定程度的影响,水动力再次加强,可能与海水倒灌或古黄河的泛滥有关。  相似文献   

30~10ka云南高山湖泊高分辨率生物记录与气候突变事件     

李宇  王倩  羊向东 《第四纪研究》2019,(4):863-877

通过对云南泸沽湖高分辨率沉积指标序列(硅藻、枝角类和孢粉)的对比分析,初步揭示了水生生物(硅藻、枝角类和水生孢粉)对末次冰盛期期间气候变化的快速响应过程.结果表明,硅藻群落组成首先响应末次冰盛期时期的开始变冷,枝角类滞后,水生孢粉则表现为渐进的响应过程.然而,泸沽湖沉积硅藻记录对末次冰期以来的短时间尺度气候快速变化的Heinrich和新仙女木事件并未有响应,揭示气候事件判别的准确性取决于指标直接响应气候的特征以及多指标的综合对比.综合西南季风区云南不同海拔湖泊沉积记录(硅藻、孢粉、摇蚊等)获得的2万年以来数据及序列表明,末次冰期千年尺度的气候突变事件( Heinrich 1、 B?lling/Aller?d暖期和新仙女木YD冷事件)在整个西南季风系统中都有反映,且气候事件变化区间及幅度存在区域差异,其根本原因是受不同气候系统、复杂地形(青藏高原)的制约.  相似文献   

南海深海表层沉积中的硅藻组合及其环境特征     

陆钧 《热带海洋学报》1999,18(1):36

定量分析了南海３３个１０００ｍ水深线以内的现代表层沉积样品中的硅藻,发现主要的种有菱形海线藻Ｔｈａｌａｓｓｉｏｎｅｍａｎｉｔｚｓｃｈｉｏｉｄｅｓ、短刺角毛藻Ｃｈａｅｔｏｃｅｒｏｓｍｅｓｓａｎｅｎｓｉｓ、结节圆筛藻Ｃｏｓｃｉｎｏｄｉｓｃｕｓｎｏｄｕｌｉｆｅｒ、长海毛藻Ｔｈａｌａｓｓｉｏｔｈｒｉｘｌｏｎｇｉｓｓｉｍａ、海洋菱形藻Ｎｉｔｚｓｃｈｉａｍａｒｉｎａ和条纹小环藻Ｃｙｃｌｏｔｅｌｌａｓｔｒｉａｔａ。根据硅藻主要种的百分含量、各站位硅藻丰度的变化以及其它一些特征,将３３个样品划分为５个硅藻组合,并着重研究这些组合与环境因素之间的关系。  相似文献   

伶仃洋东岸晚更新世以来硅藻组合及环境意义     

彭志远  陈炽新  吴聪  陈芳  周洋  余少华  贾磊  时翠 《海洋地质与第四纪地质》2021,(2):126-135

通过分析伶仃洋东岸sz17QZ-20-3钻孔硅藻分布特征,结合测年、岩性和粒度,重建了该地区晚更新世以来的古环境演化。依据沉积物岩性粒度变化判断,晚更新世时期在23.6~11.0 m层段发育了一套河床相-溺古湾相-岸滩相-冲积相的垂向沉积序列,在花斑黏土层中有海水种Ethmodiscus rex碎片的存在,指示晚更新世海侵海退旋回。早全新世海侵在9000 cal.aBP左右到达研究区,海水种硅藻含量开始迅速增加,发育滨海平原相沉积;在8000 cal.aBP左右达到最高海平面,海水种硅藻含量最高;随后研究区处于海平面停滞状态,并缓慢下降,发育浅海相沉积;中晚全新世4.2~0 m层段为海退时期,发育河口湾相沉积。中全新世4.4~4.2 m层位海水种含量突然增加和4.4~4.6 m层位贝壳碎屑层指示可能有风暴潮事件发生;晚全新世0.3~0 m层段表层沉积物中硅藻丰度异常偏高,受人类活动影响较大。  相似文献   

内蒙古克什克腾旗浩来呼热古湖泊全新世以来的环境演变   总被引：3，自引：1，他引：2  

关友义  王永  姚培毅 《地质通报》2010,29(6):891-900

利用位于中国北方季风尾闾区的浩来呼热古湖泊沉积物中的硅藻化石重建了全新世以来的环境演变历史。根据硅藻组合的变化,可将浩来呼热古湖泊全新世以来的环境演变过程划分为6个阶段:阶段Ⅰ(12.1～11.5cal ka BP),气候以寒冷为主;阶段Ⅱ(11.5～8.6cal ka BP),温度有所回升,但存在一定的冷暖波动;阶段Ⅲ(8.6～6.7cal ka BP),气候仍相对偏凉,且比较干燥;阶段Ⅳ(6.7～5.8cal ka BP),气候开始转温;阶段Ⅴ(5.8～2.9cal ka BP),气候温暖偏湿,为全新世气候最适宜期;阶段Ⅵ(2.9～0.2cal ka BP),气候趋于凉干,湖水也越来越浅,最终在0.2cal ka BP前后干涸消失。  相似文献   

Ecological variations in diatom assemblages in the Paleo-Kathmandu Lake linked with global and Indian monsoon climate changes for the last 600,000 years     

Tatsuya Hayashi  Yoshihiro Tanimura  Yoshihiro Kuwahara  Masao Ohno  Mami Mampuku  Rie Fujii  Harutaka Sakai  Toshiro Yamanaka  Takeshi Maki  Masao Uchida  Wataru Yahagi  Hideo Sakai 《Quaternary Research》2009,72(3):377-387

Variations in fossil diatom assemblages and their relationship with global and Indian monsoon climate changes for the last 600,000 yr were investigated using a core of ancient lake (Paleo-Kathmandu Lake) sediments drilled at the Kathmandu Basin, Nepal Himalaya. Chronological scales of the core were constructed by tuning pollen wet and dry index records to the SPECMAP δ¹⁸O stack record. Examinations of biogenic silica contents and fossil diatom assemblages revealed that variations in productivity and compositions of diatom assemblages were closely linked with global and Indian monsoon climate changes on glacial and interglacial time scales. When summer monsoonal rainfall increased during interglacials (interstadials), diatom productivity increased because of increased inputs of terrestrial nutrients into the lake. When summer monsoonal rainfall reduced and/or winter monsoonal aridification enhanced during glacials (stadials), productivity of the diatoms decreased and lake-level falling brought about changes in compositions of diatom assemblages. Monospecific assemblages by unique Cyclotella kathmanduensis and Puncticulata versiformis appeared during about 590 to 390 ka. This might be attributed to evolutionary fine-tuning of diatom assemblages to specific lake environmental conditions. Additionally, low-amplitude precessional variations in monsoon climate and less lake-level changes may have also allowed both species to dominate over the long periods.  相似文献   

Microphytobenthic biomass and species composition in intertidal flats of the Nakdong River estuary, Korea   总被引：1，自引：0，他引：1  

GuoYing Du  Moonho Son  Misun Yun  Soonmo An  Ik Kyo Chung   《Estuarine, Coastal and Shelf Science》2009,82(4):663-672

Intertidal microphytobenthos (MPB) were investigated monthly from August 2006 to March 2008 at four different sites in the sand flats of Nakdong River estuary, Korea. Samples of surface sediment (ca. 1 cm) were collected, and chlorophyll a was extracted as biomass estimation. Species identification and enumeration were carried out by light microscopy, assisted where necessary by scanning electronic microscopy. Biomass varied between 0.47 and 16.58 μg cm⁻³, abundance changed from 5.25 to 414.75 × 10³ cells cm⁻³, while the Shannon diversity indexes ranged between 0.69 and 2.35 H′. Thirty-nine MPB taxa were identified, primarily composed of epipelic diatoms, among which Amphora and Navicula were the most abundant genera. Based on the biomass, abundance, species composition and their dynamics, MPB assemblages of sampling sites were grouped into three distinct communities corresponding to their sediment composition characteristics. Multivariate correlation analysis revealed that biomass was positively related to mud and very fine sand, negatively related to fine and medium sand, but not significantly related to environmental factors such as pore water nutrients, light intensity and salinity, which fluctuated rapidly during emersion period. Cluster analysis corroborated the division of MPB communities according to site types on seasonal scales, and also showed seasonality between sites by cluster of all summer groups. Principal component analysis identified that variability in species composition was significantly affected by mud, very fine sand, fine sand, light intensity, and sediment temperature. This study suggests that sediment composition plays an important role in the functioning of intertidal MPB communities in estuarine ecosystems.  相似文献