大型水母沙海蜇暴发的温带贫营养海洋生态系统中细菌和浮游植物的关系     

曾阳  黄旭光  黄邦钦  米铁柱 《海洋学报(英文版)》2016,35(10):107-113

Bacterial abundance, phytoplankton community structure and environmental parameters were investigated to study the relationships between bacteria and phytoplankton during giant jellyfish Nemopilema nomurai blooms in the central Yellow Sea during 2013. N. nomurai appeared in June, increased in August, reached a peak and began to degrade in September 2013. Results showed that phosphate was possible a key nutrient for both phytoplankton and bacteria in June, but it changed to nitrate in August and September. Phytoplankton composition significantly changed that pico-phytoplankton relative biomass significantly increased, whereas other size phytoplankton significantly decreased during jellyfish bloom. In June, a significantly positive correlation was observed between chlorophyll a concentration and bacterial abundance(r=0.67, P0.001, n=34).During jellyfish outbreak in August, there was no significant correlation between phytoplankton and bacteria(r=0.11, P0.05, n=25), but the relationship(r=0.71, P0.001, n=31) was rebuilt with jellyfish degradation in September. In August, small size phytoplankton occupied the mixed layer in offshore stations, while bacteria almost distributed evenly in vertical. Chlorophyll a concentration significantly increased from(0.42±0.056) μg/L in June to(0.74±0.174) μg/L in August, while bacterial abundance just slightly increased. Additionally, the negative net community production indicated that community respiration was not entirely determined by the local primary productivity in August. These results indicated that jellyfish blooms potentially affect coupling of phytoplankton and bacteria in marine ecosystems.  相似文献   

土壤添加物对土-水曲线和土体收缩的影响   总被引：3，自引：0，他引：3       下载免费PDF全文

邢旭光  柳烨  马孝义 《水科学进展》2016,27(1):40-48

为探索不同添加物(小麦秸秆、麦壳和植物油渣)对土壤持水性能和土壤收缩特性的影响,定量掺混3种粉末,采用离心机法测定土-水曲线,并对土壤持水能力和土壤收缩特征进行评价。结果发现:各处理土-水曲线形态无差异,van Genuchten模型可用于此条件土-水曲线拟合;3种添加物均可提高土壤容重和土壤含水率并利于保水,且土壤持水能力表现为油渣 >麦秆 >麦壳 >纯土;随着土壤脱水,土体以轴向收缩为主,三直线模型可用于土壤收缩曲线拟合,土体线缩率与吸力和含水率分别满足对数和Logistic函数关系;土体几何收缩量表现为麦壳 <油渣 <麦秆 <纯土,土壤开裂程度表现为油渣 <麦秆 <麦壳 <纯土。  相似文献   

电磁波手段中强震前短临异常特征研究   总被引：3，自引：0，他引：3  

董旭光  苏鸾声 《东北地震研究》1998,14(4):46-53

本文通过对电磁波台站观测观测资料的研究,分析了山东地区各台站对于中强震的映震能力,同时,讨论了中强震前电磁波的短临异常特征。  相似文献   

地球物理方法在猫岭金矿预测中的应用     

伍旭光 《吉林大学学报(地球科学版)》1998,(3)

航空磁测、地面磁测、电法及能谱测量等地球物理方法可以为猫岭金矿矿产预测提供可靠信息,利用这些信息可以对成矿地质环境分析、地球物理找矿模型建立及含金蚀变带的深部变化等进行科学地推断。  相似文献   

Simplification of the Gardner model: effects on maximum upward flux in the presence of a shallow water table     

Xing  Xuguang  Ma  Xiaoyi 《Hydrogeology Journal》2018,26(4):1117-1122

Hydrogeology Journal - The maximum upward flux (Emax) is a control condition for the development of groundwater evaporation models, which can be predicted through the Gardner model. A...  相似文献   

基于机器学习的铁路桥墩地震损伤快速评估          下载免费PDF全文

沈林白  洪彧  周志达  蒲黔辉  文旭光 《地震工程学报》2024,(1):95-104

在桥梁的震后抢通工作中,桥梁结构的快速损伤评估是恢复交通的关键环节。以具有代表性的铁路矩形桥墩为研究对象,通过4组拟静力试验验证有限元建模方法的合理性,并对1 000组桥墩有限元模型分别按照纵桥向和横桥向进行耐震时程分析,通过搭建BP神经网络对地震动力响应的需求结果进行拟合,构建铁路矩形桥墩震损快速评估模型,最终通过一座三跨混凝土梁桥验证该模型的适用性。研究结果表明：配筋率、配箍率、剪跨比和轴压比是影响桥墩地震损伤的四种主要因素,长宽比、混凝土和钢筋强度是影响桥墩地震损伤的三项次要因素;当发生PGA为0.32g的设计地震时,通过数值分析和神经网络模型快速评估这两种方法计算所得桥梁四个桥墩轻微损伤概率分别为96.7%、44.6%、49.1%、96.7%和95.6%、40.4%、60.9%、95.8%,中度损伤概率分别为40.1%、1.2%、1.6%、40.1%和37.4%、2.3%、6.0%、37.7%;BP神经网络算法能够有效建立构造参数与地震响应之间的联系,输出误差处于合理范围内,回归程度较好。基于BP神经网络的桥梁地震损伤评估模型具有较好的普适性,能替代部分数值仿真计算工作。  相似文献   

复合隔震摩擦承压比的振动台试验研究     

杨树标  李旭光  马裕超  孙丰光 《世界地震工程》2010,26(2)

对复合隔震结构的重要参数之一摩擦承压比进行了振动台试验研究,分析试验结果表明摩擦承压比对复合隔震结构的减震效果影响很大,并且存在合理取值范围.合理的摩擦承压比取值可以使复合隔震结构的地震反应比橡胶支座隔震结构小.因此复合隔震结构具有显著的优越性.  相似文献   

贵州水城地区晚二叠世含树皮体煤成烃特性研究   总被引：5，自引：0，他引：5  

孙旭光  秦胜飞 《地球化学》1999,28(6):605-612

采用岩石热解、热解气相色谱以及有机岩石学等方法。对贵州水城含树皮体煤及其主要组分－－树皮体的生烃潜力、烃类组成特征和成烃演化规律进行了详细的研究。结果表明：本区含树皮体煤友及树皮体的生烃潜力、氢指数和扔机碳含量都较高,含树皮 煤主要生烃温度区间和生烃高峰期分别为４００￣５００℃和４２０￣４５０℃;热模拟产物以轻质烃（凝析油或轻质油）占绝对优势,湿气次之;气态烃与液态烃演化模式截然不同,液态烃产率在  相似文献   

A preliminary study on benthos food web structure of tidal zone in the Laoshan Bay by using stable carbon isotopes     

Cai Deling  Hong Xuguang  Mao Xinghu  Zhang Shufang  Gao Sulan 《海洋学报(英文版)》2000,19(4):81-89

By analyses of carbon isotopic composition(δ¹³C values) of the benthos collected in the Laoshan Bay in August 1993 and February and May 1994, it is found that the main food sources of the benthos can be divided into four groups in terms of carbon isotope composition: Particulate Organic Matter (POM),benthic diatoms, benthic macroalgae and the organic matter in sediments.The results show that the carbon isotopic composition of the benthic animals has a close relation with that of the food they take in.The carbon isotopic compositions of benthos may be useful in elucidating their food sources.The carbon isotopic data have confirmed that POM is the main food source of the benthic filter feeders such as bivalves; crustaceans have a wide range of δ¹³C values, showing their food source has diversity; benthic diatoms are an important fraction of the food for most of gastropods.A preliminary investigation of the benthic-pelagic coupling in that region using the stable carbon isotopic tracers has confirmed the importance of POM as a food source for benthos in this region,but the organic matter in sediments and benthic diatoms are also relatively important for a lot of benthic animals.The benthic-pelagic coupling in the Laoshan Bay temperate ecosystem is not so tight as that in ecosystems at higher latitudes such as north-eastern water polynya.  相似文献   

基于网络药理学探讨赤芍抗血吸虫病及肝纤维化的作用机制          下载免费PDF全文

孙绪光  赵颀涵  彭韵嘉  陈甄  曾辉霞 《应用海洋学学报》2023,39(9):169

目的：通过网络药理学方法探讨赤芍有效成分治疗血吸虫病及肝纤维化的潜在作用机制。方法：通过TCMSP数据库检索并收集赤芍有效成分及其对应的作用靶点,借助UniProt数据库将靶点蛋白的genename转换为genesymbol;通过GeneCards、OMIM、TTD疾病数据库搜集血吸虫病及肝纤维化相关靶点;将赤芍成分靶点和疾病靶点取交集,获得赤芍治疗血吸虫病及肝纤维化的潜在靶点,利用Cytoscape 3.8.2软件构建“药物-成分-靶点-疾病”和“成分-靶点-通路”网络;通过STRING数据库对交集靶点进行蛋白质-蛋白质相互作用（PPI）网络分析,采用Cytoscape 3.8.2软件进行分析和可视化呈现;通过Metascape数据库进行基因本体（GO）功能、京都基因与基因组百科全书（KEGG）通路富集分析。结果：筛选得到赤芍活性成分29种,成分靶点与血吸虫病及肝纤维化疾病的交集靶点19个,其中肿瘤抑制蛋白（TP53）、前列腺素内过氧化物合酶（PTGS2）、肿瘤坏死因子（TNF）、基质金属蛋白酶9（MMP9）、白细胞介素-6（IL-6）、血管内皮生长因子A（VEGFA）、白细胞介素8（IL-8）、缺氧诱导因子1A（HIF1A）、转化生长因子B1（TGFB1）、基质金属蛋白酶2（MMP2）为核心靶点,涉及的主要信号通路为癌症信号通路、乙型肝炎、糖尿病并发症中的晚期糖基化终产物及其受体（AGE-RAGE）信号通路、动脉粥样硬化。结论：本研究初步预测了赤芍抗血吸虫病及肝纤维化的作用机制,可为今后药效物质基础研究提供参考。  相似文献