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我国东南近岸海域表层沉积硅藻组合 总被引：1，自引：0，他引：1
对采自我国东南近岸海域18个站位78个表层沉积样品进行了硅藻鉴定分析,根据硅藻优势种和次优势种的分布特征,划分出3个组合和两个亚组合,其较好地对应分布于南海、台湾海峡和东海等3个近岸海域。统计数据表明,近岸海域表层沉积硅藻的分布受大陆入海径流的影响微乎其微,随着水深的增加,我国东南近岸海域海洋初级生产力减小,底栖种、潮间带种减少而浮游种增加;组合Ⅰ的分布表明南海东北部海域明显受黑潮流等外洋水团的影响,可应用组合Ⅱ1和组合Ⅱ2中优势种和特征种硅藻来指示水深,两亚组合面貌的差异是对冬夏两季海峡两侧受不同性质海流控制的响应;组合Ⅲ受沿岸流控制比较明显,而遭受黑潮等外洋水团的影响很弱。 相似文献
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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
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表层沉积物中硅藻的分布及组合特征对于研究相应的海洋环境有着重要的意义。东南极普里兹湾及其附近海域的22站表层沉积物中鉴定出硅藻36种,分属13属,其中Fragilariopsis curta在普里兹湾内占36.76%~66.36%,Fragilariopsis kerguelensis在湾外开阔水域占54.33%~70.95%。除趋势对应分析(DCA)显示研究区主要的10种硅藻分为开放水域种组合、近海冰种组合和海冰种组合,其表层沉积硅藻组合分布也分成3个区。作为硅藻极地开放海洋指示种的Fragilariopsis kerguelensis分布在普里兹湾外的深海平原,受湾内冰架水的限制,不能向湾内扩散;作为硅藻海冰指示种的Fragilariopsis curta主要分布在普里兹湾内的陆架上,受南极表层水和海冰的影响较重,在湾外受深水溶解作用而急剧减少;作为硅藻近海冰指示种的Thalassiosira antarctica的出现是受普里兹环流、冰架水和海冰的控制。研究区硅藻的组成和分布反映和验证了区域内环流的分布和扩散极限。 相似文献
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北冰洋西伯利亚陆架海是北极气候快速变化最为显著的海域之一,而沉积硅藻作为极地海洋生态系统的重要组成部分,对环境变化具有敏感的响应。对楚科奇海、东西伯利亚海和拉普捷夫海表层沉积物开展了硅藻组成鉴定,利用典型对应分析方法分析了硅藻属种与1986～2015年环境变量之间的关系。结果表明,夏季和秋季海冰密集度、表层海水盐度是影响研究区表层硅藻分布特征最主要的因素。此外,根据表层站位与环境变量的典型对应分析,可将西伯利亚极地海域划分为4个区域,分别为海冰硅藻组合带、暖水硅藻组合带、沿岸硅藻组合带和混合硅藻组合带。这些表层站位的分区与相应区域的海流模式有明显的相关性,海冰硅藻组合带仅分布于研究区北部的高纬度地区;暖水硅藻组合带位于受白令水和太平洋海水的分支——阿拉斯加沿岸水影响为主的区域;拉普捷夫海南部的沿岸硅藻组合带则受到河流径流和西伯利亚沿岸流的强烈影响;混合硅藻组合带受极地冷水、海冰覆盖、太平洋暖水和陆地径流的共同影响。 相似文献
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珠江口外表层沉积物中硅藻分布特征 总被引：3，自引：0，他引：3
本文根据我所在南海大陆架综合调查所采集的珠江口外表层沉积样品(112°—115°E,19°—23°N),共研究44个硅藻样(图1)。根据硅藻属种分布差异,可以了解当时的沉积环境,它的遗壳又极易被海流搬运,是研究海流的运动、古地理环境等的重要手段之一。笔者在本海区共鉴定45属164种,统计了其数量(每克干样的硅藻数),根据其参数大小及硅藻植物群在沉积物中的分布,探讨珠江口外海域不同地形地貌、沉积物类型、水动力性质、温度和盐度对沉积硅藻属种及其含量分布的影响,不同组合在各海区中的分布特征,利用硅藻生态特点了解当时的沉积环境。 相似文献
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中国近海表层沉积硅藻 总被引：7，自引：0，他引：7
本文分析了中国近海表层沉积物129个硅藻样品.根据样品中硅藻优势种、特征种的数量变化,把中国近海表层沉积硅藻划分为若干反映不同沉积环境的硅藻组合,并讨论了硅藻组合与深度、温度、盐度和海流等海洋主要环境因素之间的关系. 相似文献
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通过对取自南海62个站位的表层沉积物样品,进行了硅藻、沉积物粒度分析,查明了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个种和变种、变型.种类以热带外洋种为优势,如Azpeitia nodulifer、Roperia tesselata、Azpeitia africanus、Hemidiscus cuneiformis、Nitzschia marine 等,伴有一定量的热带—亚热带近岸种和广布种如Paralia sulcata、Thalassiosira excentrica、Cyclotella stylorum、Thalassionema nitzschioides、Thalassiothrix longissoma等.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.研究海区硅藻种类组成与临近的菲律宾海域相似程度最大,其次是东海、太平洋东北部海域.对影响南海表层沉积硅藻分布的主要因素进行了探讨,南海表层沉积硅藻主要受海底地质地貌、沉积速率、水动力条件和水文气候条件等的影响较大,硅藻的分布往往是这些因素综合作用的结果. 相似文献
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福建近海不同海洋功能区冬季浮游植物群落结构的比较研究 总被引：2，自引：1，他引：1
2006年12月～2007年1月对福建省沿岸近海的浮游植物群落结构进行了大面积科学调查研究。结果表明,冬季福建近海浮游植物隶属于55属112种(含变种、变型),其中硅藻48属97种(含变种、变型),甲藻5属10种,蓝藻1属2种,金藻1属3种。硅藻类在种类和细胞丰度上均占主导地位,甲藻类多分布在闽中近海及东山沿岸,蓝藻类检出率降低,金藻类检出率增高。表层浮游植物平均丰度为422.31×102个/dm3,丰度分布呈闽南高,闽中次之,闽东低的态势。叶绿素a的分布与浮游细胞丰度分布大体一致,但在闽中、闽东近海存在近岸与远海的差异,与优势类群的水平分布也有差异。福建近海赤潮生物种类较多,是引发赤潮的潜在生物因素,一些赤潮生物已在闽南、闽中局部海域成为优势种。与以往同期资料比较,硅藻优势类群发生明显变化,甲藻种类数和细胞丰度增多;浮游植物细胞丰度明显增加,但水平分布变化不大。 相似文献
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通过对三沙湾24个站位表层沉积物样品进行硅藻分析,共鉴定硅藻31属84种（包括变种和变型）,其中夏季和冬季分别鉴定出31属71种和31属67种,主要属种以中心纲硅藻为主,如爱氏辐环藻（Actinocyclus ehrenbergii）、波状辐裥藻（Actinoptychus undulatus）、横滨盒形藻（Biddulphia grundleri）、中心圆筛藻（Coscinodiscus centralis）等.在生态习性上,底栖海水种占绝对优势.硅藻丰度从湾顶向湾外递减,夏季丰度高于冬季,平均丰度分别为9 003个/g和6477个/g.沉积物粒度分析显示,三沙湾表层沉积物以粉砂质粘土为主,研究表明三沙湾硅藻丰度与平均粒径存在一定相关性,夏季硅藻丰度变化范围为2 104～28 209个/g,粒径范围为5.26～7.36Φ,硅藻丰度与平均粒径变化范围都较大;而冬季硅藻丰度变化在1 929～14 372个/g之间,粒径范围为5.51～6.98Φ,相对夏季其变化较小,论证了水动力是影响硅藻沉积分布的一个重要因素.对影响三沙湾表层沉积硅藻分布的主要环境因子进行探讨,三沙湾表层沉积硅藻主要受潮流、深度和盐度等影响较大. 相似文献
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硅藻在全球碳循环中发挥着重要的作用。"树荫种"硅藻在次表层水体中的勃发成席,并迅速埋藏成为硅藻席沉积,使人们逐渐意识到次表层生产在整个生产力及输出生产中起着重要作用。介绍了首次在低纬度西太平洋区域发现的硅藻席沉积的分布特征,硅藻席发现站位呈带状分布,大致呈北西-南东向展布,大部分散布在17.5°～20°N之间。采集到硅藻席沉积物的站位其水深在碳酸钙补偿深度(CCD)以下4837～6150m的深水区,多分布在较平坦的海底,且受风力和陆源物质输入影响相对较强的区域。该区域硅藻席的形成可能是由于末次冰期时该海区有大洋锋面的形成所致。该区域的成席硅藻Ethmodiscus rex(Wallich)Hendey为典型的"树荫种"硅藻,可以通过自身调节浮力的作用,在水体相对稳定的贫氧大洋中生存并勃发成席。末次冰期低纬度西太平洋硅藻席沉积的发生,可能使该区成为CO2的汇。 相似文献
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Winter Distribution of Diatom Assemblages in the East China Sea 总被引：3，自引：0，他引：3
We examined the spatial distributional relationships between diatom assemblages and water types during the winter in the East China Sea. Principal component analysis was used to identify two water types and two diatom assemblages in the study area. Coastal water types along the mainland China coastline had low temperature and salinity levels, but high nitrate levels. The shelf-mixing water type in the rest of the study area had higher temperatures and salinities and lower levels of nitrate. Diatom assemblage distribution was not spatially consistent with water type. The Kuroshio assemblage had a large standing stock, distributed along the surface of the shelf break. This assemblage is likely the result of Kuroshio surface water coming into contact with nutrient-rich water in the shelf area, triggering proliferation of certain diatom species. A background assemblage with low standing stock level persisted over the entire study area in both coastal water and the shelf-mixing water types. Our results support previous research: the background assemblage is due to poor growth conditions such as the convection of water during winter; there were no significant seasonal variations in the species composition. 相似文献
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2004-2016年夏季长江口网采浮游植物及其影响因素 总被引：1，自引：0，他引：1
基于2004-2016年夏季长江口生态监控区13年的生态环境调查数据，开展网采浮游植物年际变化及其与环境因子关系研究。结果表明：（1）共鉴定出浮游植物7门263种，以硅藻占绝对优势，甲藻次之，物种数呈增加趋势，其中硅藻种类数占有比下降，而甲藻的种类数占有比呈上升趋势；（2）总细胞丰度、硅藻细胞丰度和甲藻细胞丰度都呈上升趋势，除2014年外，其余年份硅藻细胞丰度都占绝对优势并与总细胞丰度的分布曲线和变化趋势基本一致；（3）水平分布模式及其年际变化受环流变化和水团消长的影响，总体趋势是河口区细胞丰度较低，由河口到外海呈逐渐增大趋势，部分年份呈现先增大后减小的趋势；（4）生物多样性多年呈下降趋势，物种组成随空间和时间变化较大，只有较少的种类能够保持稳定，多数物种只是偶尔被检出；（5）中肋骨条藻有10年为区域第一优势种，41种常见种中有31种细胞丰度呈增加趋势，10种细胞丰度呈下降趋势。（6）浮游植物细胞丰度与活性磷酸盐和无机氮具有相关性，种类数、多样性指数除了与溶解氧、氨氮、叶绿素a无相关性外与其他10种环境因子都相关。本研究能够较好反映研究区域浮游植物的本底情况及演变趋势。 相似文献
14.
Suk Min Yun Taehee Lee Seung Won Jung Joon Sang Park Jin Hwan Lee 《Ocean Science Journal》2017,52(3):345-357
The fossil diatom assemblage record from two sediment cores obtained from the Ulleung Basin, East Sea, Republic of Korea, revealed changes in the diatom assemblage zones in PG1 and PD3 core samples. The two sediment cores were δC14 dated and approximately represented the late Pleistocene–Holocene. The analysis of age zones in the PG1 core and PD3 core was assessed based on the frequency of variations, and occurrences of biostratigraphical fossil diatom species. During the Last Glacial Maximum (LGM), the sea level was lower than that at present and the Ulleung Basin became isolated from the Pacific Ocean. As a result, there would have been a limited Tsushima Warm Current (TWC) influence, and salinity would have decreased resulting in increased freshwater and coastal diatoms. The distribution pattern of diatoms presented in the cores was associated with changes in water temperature and salinity and the adding of terrigenous material brought about by the input of freshwater. Changes in the abundance of a tychopelagic diatom, Paralia sulcata, reflected the effect of the water currents. Diatom temperature (Td) values and the ratio of centric/pennate diatoms provided evidence of limited influences of the TWC and freshwater inflow. It is thought that all assemblage zones were influenced by the TWC, which had an important effect on the distribution and composition of fossil diatoms. 相似文献
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An array of four sediment trap moorings recorded the particulate flux across the Antarctic Circumpolar Current (ACC) at 170 °W, between November 1996 and January 1998, as part of the US JGOFS-Antarctic Environment and Southern Ocean Process Study (AESOPS) program. The trap locations represent sampling within the Polar Frontal Zone, the Antarctic Polar Front, the Antarctic Zone and the Southern Antarctic Zone. Here we report observations from 1000 m below the sea-surface compared to seafloor and surface water distributions. Sub-sample splits from each trap were obtained and total diatom flux and species composition were determined. The diatom fluxes were quantified using both a dilution and a ‘spike’ method to allow for the rapid repeatability of measurements. Diatom flux was found to be highly seasonal across the ACC particularly at higher latitudes. Marine snow aggregates of intact diatom cells and chains were the major components of the biogenic flux. Siliceous particle size was noted to decrease with increasing latitude, which could be aligned with a shift of the diatom assemblage to small-size species/sea-ice affiliated species. A ‘double-structured’ diatom flux was recorded at the location of the Antarctic Polar Front trap, with a shift in the diatom assemblage from larger to smaller diatoms in the second flux episode. The sediment trap assemblage shows deviations from the surface water assemblage, while surface sediment samples indicate that significant dissolution occurs after 1000 m and at the sediment–water interface. Estimation of diatom biovolumes across the ACC shows that large diatoms have the potential to greatly impact biogenic fluxes to the ocean interior despite their low fluxes. Small species of the genus Fragilariopsis could potentially export as much Corg as Fragilariopsis kerguelensis near the retreating ice edge. However, their low abundance in the surface sediments also suggests that these diatoms are a shallow export species. 相似文献
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Abstract. The horizontal distribution of phytoplankton in relation to changes in the physico-chemical conditions of a eutrophic semi-enclosed embayment is described. Phytoplanktonic populations derived from a station interval of 6 miles (coarse scale variations) were compared by quantitative (standing stock) and qualitative (species composition, diversity, Diatom/Flagellate ratio) criteria. The results showed that quantitative and qualitative parameters differed in their sensitivity and were affected differently by environmental perturbations. Along a horizontal transect with defined variations in nutrient concentrations, changes in standing stock levels were not significant, but differences in species composition existed and caused coefficients of variation between stations for species diversity up to 50% and of the Diatom/Flagellate ratio up to 120%. Furthermore, distributional differences among certain flagellate species (Prorocentrum micans, Prorocentrum balticum) and diatom species (Nitzschia closterium, Chaetoceros curvisetus) were recorded which showed that the flagellate species were distributed more uniformly than the diatoms along a transect with progressive decrease in nutrient concentrations. 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
18.
南海北部和中部硅藻通量季节性变化及其对季风气候的响应 总被引：2，自引：2，他引：0
通过对南海北部和中部两套时间序列沉积物捕获器中的颗粒物样品进行硅藻分析,揭示了南海北部和中部硅藻通量的季节变化规律及其区域差异和各自对东亚季风气候的响应.研究表明在南海北部和中部海域,硅藻通量可以在一定程度上指示海洋初级生产力水平,其中南海北部硅藻通量明显低于中部,这可能与北部颗粒物样品采集期间发生的E1 Ni(n)o... 相似文献