乌鲁木齐东道海子剖面的硅藻记录与环境演变   总被引：8，自引：4，他引：4  

李树峰  阎顺  孔昭宸  倪健 《干旱区地理》2005,28(1):81-87

通过分析乌鲁木齐河尾闾湖泊东道海子剖面的硅藻记录,结合孢粉、磁化率、烧失量和粒度分析资料,以^14C测年数据为基础,讨论了天山北麓古尔班通古特沙漠南部边缘的环境演变。研究认为：东道海子地区在4900aBP～3120aBP这一时段气候较稳定,3120aBP以来,有几次波动;湖泊的高湖面期与气候的冷期对应,湖泊的盐碱度较低,硅藻以及水生、沼生植物生长较繁盛;湖泊的中湖面期与气候的暖期对应,湖泊的盐碱度较高,硅藻以及水生、沼生植物生长较稀少。  相似文献   

不同藻类生态参数在反演沉积物环境中的应用比较     

刘东艳  邸宝平  石雅君  申旭红  李欣 《海洋学报》2013,35(2):154-160

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   

Late Quaternary diatom and sea level changes in estuarine plain of the Jiulong River     

Chen Wenrui  Lan Dongzhao  Chen Chenghui 《海洋学报(英文版)》1998,17(4):509-518

TheJiulongRiver,composedoftheWestStream,theNorthStreamandtheSouthStream(seeFig.1)isthesecondlargestriverinFujianProvince.ItsestuarineplainintervenesbetweenthetwqcitiesofXiamenandZhangzhou,withsouthern-subtropicoceanicmonsoonclimate-SofartherehasnotbeensystematicresearchontheLateQuaternarysea1evelchangesinthearea,andthispaperisintendedtodosomethingaboutit.DIAToMZoNESANDBIoFACIESOFZK5BoREHOLETheBoreholeZK5islocatedtothenortheastofHaichengTown,withcoordinateof24"24,32*N,ll7'5…  相似文献   

细菌细胞膜脂记录的西太平洋暖池约4Ma以来沉积物风尘陆源输入变化     

赵小小  吴玥汀  董良  章陶亮  胡邦琦  李清  王风平 《海洋地质与第四纪地质》2021,41(1):52-60

西菲律宾海作为西太平洋暖池的一部分,重建其在地质历史时期的热力学变化、陆源输入变化,对于理解西太平洋暖池在全球地质时间尺度上的作用具有重要意义。利用古菌与细菌的细胞膜质甘油二烷基甘油四醚(glycerol dialkyl glycerol tetraethers,GDGTs)对西菲律宾海XT-47孔沉积物的陆源输入及其上方水体温度的变化进行重建,发现该沉积柱顶部(0~260 cm,约16.6~18.8 ka)BIT指标为0.01~0.2,TEX^H 86重建的上层海水平均温度为22.5℃,而底部(260~632 cm,约18.8~4000 ka)TEX^H 86重建得到的上层海水温度绝对值波动剧烈(0.6~26℃),在此范围内BIT>0.3,并呈现逐渐增加的趋势,超过BIT界定的陆源输入对TEX^H 86重建古温度有效性的阈值,这导致了该深度范围内TEX^H 86重建古温度变化的严重偏差。以260和470 cm为界,该沉积柱的沉积相出现明显变化,上层为大量纹层硅藻席沉积,中层为远洋黏土和硅藻泥互层,下层为远洋黏土沉积;同时,支链GDGTs(branched GDGTs,br GDGTs)的组成也出现明显差异,说明其来源可能有所不同。基于以上分析,提出260 cm以浅,brGDGTs可能主要为海相原位自生为主;而260 cm深度以下,主要以风尘输送的陆源brGDGTs为主。该结果显示陆源输入的变化可以间接反映东亚冬季风的强弱,本研究为高低纬之间的海陆相互作用研究提供了新的视角。  相似文献   

Redeposition of volcaniclastic sediments by a tsunami 4600 years ago at Kushima City,south-eastern Kyushu,Japan     

Masaki Yamada  Shigehiro Fujino  Takashi Chiba  Kazuhisa Goto  James Goff 《Sedimentology》2020,67(3):1354-1372

The Hyuga-nada Sea, south-eastern Kyushu, Japan, is located between a strong (Nankai Trough) and a weak interplate coupling zone (Ryukyu Trench). Over the past 400 years this area has only experienced Magnitude 7·5 earthquakes or smaller and associated small-scale tsunamis. However, this short historical record most likely does not include the full range of high magnitude, low frequency giant earthquakes that might have occurred in the region. Thus, it is still unclear whether giant earthquakes and their associated tsunamis have occurred in this region. This paper reports on a prehistoric tsunami deposit discovered in a coastal lowland in south-eastern Kyushu facing the Hyuga-nada Sea. There is a reddish-brown pumiceous layer preserved in a non-marine, organic-rich mud sequence obtained from onshore sediment cores. This layer is recognized as the ca 4600 year old Kirishima-Miike tephra (that is now placed around 4500 years ago) sourced from Mount Kirishima, southern Kyushu. Another whitish pumiceous layer is evident below the Kirishima-Miike tephra in almost all of the sediment cores. A relatively high percentage of marine and brackish diatoms is recorded within this lower pumiceous layer (but not in the surrounding muds or in the overlying Kirishima-Miike tephra), indicating a marine or beach sediment source. Plant material obtained from organic-rich mud immediately below the event layer was dated to ca 4430 to 4710 cal yr bp , providing a limiting-maximum age for this marine incursion event. The presence of marine diatoms below the event layer is probably explained by pre-seismic subsidence. An absence of the resting spore of the planktonic brackish diatom Cheatoceros and the appearance of the freshwater diatom Eunotia serra immediately above the event layer probably represents a marked change to a relatively low-salinity environment. Assuming that there were no significant local geomorphological changes, such as drainage obstruction caused by formation of a new barrier spit, it is considered that co-seismic or immediate post-seismic uplift are the most likely explanations for this notable environmental change. Based on the crustal movements noted before and after the marine incursion, this event is interpreted here as an earthquake-generated tsunami. Moreover, because of these notable seismic crustal movements the tsunamigenic earthquake probably occurred immediately offshore of the study site.  相似文献   

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   

多胺对3株硅藻生长的影响          下载免费PDF全文

赖雯奕  娄亚敏  徐继林  周成旭  严小军 《海洋学研究》2018,36(3):96-100

为探究多胺对硅藻生长的影响,以精胺、亚精胺、腐胺、尸胺和苯乙胺为外源多胺,对角毛藻Chaetoceros sp.、小新月菱形藻Phaeodactylum tricornutum Bohlin以及威氏海链藻Conticribra weissflogii进行室内添加培养。结果表明:同一温度下,不同多胺对不同硅藻生长存在特异性差异。亚精胺对角毛藻的生长起促进作用;尸胺对小新月菱形藻起促生长作用,而精胺对小新月菱形藻起抑生长作用;多胺对威氏海链藻生长前期(13 d前)主要起促生长作用,后期起抑生长作用(13 d后)。因此,适时适量添加多胺可有效促进硅藻的生长,提高硅藻的繁殖效率。  相似文献   

中国南麂列岛产海洋底栖硅藻新种-南麂侧链藻(Pleurosira nanjiensis sp. nov.)的形态与分子系统学研究     

李宇航  南云保  徐奎栋 《海洋学报(英文版)》2018,37(10):33-39

本文描述了采自南麂列岛小柴屿岩相潮间带的一海洋底栖硅藻新种，南麂侧链藻（Pleurosira nanjiensis sp.nov.）。本研究使用光学显微镜和扫描电子显微镜对该种进行了形态学观察，并基于SSU rRNA和rbcL基因重建了其系统发育关系。南麂侧链藻具有壳面橄榄形、椭圆形或圆形，壳面隆起，单眼突出于壳表面，2–3个唇状突（rimportulae），放射排列的线纹等特征，区别于其他侧链藻。  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   

Early Holocene shore displacement and evidence of irregular isostatic uplift northwest of Lake Vänern, western Sweden     

Jan Risberg  Per Sandgren  Elinor Andrén 《Journal of Paleolimnology》1996,15(1):47-63

In the 1920's the Swedish geologist Lennart von Post found evidence of irregular early Holocene isostatic uplift in the region northwest of Lake Vänern in western Sweden. von Post based his conclusions on levellings of ancient shore lines. These were indirectly dated by pollen stratigraphical investigations in basins situated at approximately the same altitudes as the shore lines. To test von Post's hypothesis, we have adopted a different methodological approach. The sediments in twelve small lake basins, within five minor areas in this region, have been investigated with respect to when they became isolated from ancient Lake Vänern. Initially all the lake thresholds were levelled. Altitudes range between 165 and 96 m above sea level. By combining the results of mineral magnetic and diatom stratigraphical analyses it has been possible to determine the level in the sediment when the basin became isolated. The ¹⁴C age of this isolation level has been inferred from AMS dates based on the NaOH-soluble fraction of bulk sediment, partly with very low organic content. Altogether, 36 radiocarbon datings have been carried out, ranging from 10080 to 8800 ¹⁴C years BP. Pollen analyses, and subsequent correspondence analysis (CA) of all pollen spectra, were carried out around the isolation level in each basin as a complement to the AMS datings.If the region had been subject to irregular isostatic uplift, lakes at the same altitude in the five areas should have been isolated at different times. The AMS determined isolation ages, corrected according to CA of the pollen stratigraphy and compensated for the relatively higher rebound of the northerly situated sites support von Post's conclusion, from the beginning of this century, that the region northwest of Lake Vänern has been subjected to irregular isostatic uplift.  相似文献