Changes in the population structure of Calanus sinicus during summer–autumn in the southern Yellow Sea

Calanus sinicus is a calanoid copepod widely distributed in coastal waters of China and Japan, and oversummering strategies may have major impacts on their population dynamics which in turn affect local marine food web structure. The abundance, stage composition, and sex composition of the planktonic copepod C. sinicus were studied from August to October 2002 in the southern Yellow Sea to understand how its population recovers from the over-summering state. Results showed that C. sinicus had low reproduction in August due to high temperature, except in waters near the Cheju Island with rich food and moderate bottom temperature, but the reproduction rates here decreased in September–October as food availability declined. When temperature dropped in September–October, C. sinicus actively propagated in coastal shallow waters. However, reproduction rates of C. sinicus individuals inhabiting the Yellow Sea Cold Water Mass(YSCWM) remained low during the three months of the study. The percentage of C. sinicus females was high during the reproductive period, which suggests that the sex composition of adult C. sinicus may reflect whether or not the population is in the reproductive mode.Numerous fifth copepodite stage(CV) C. sinicus aggregated in the YSCWM in a suspended developmental stage during the three months of this study, and they potentially served as the parental individuals for population development when conditions became optimal for reproduction later in the year.     

南极夏季南设德兰群岛东部海域南极大磷虾的摄食策略

Euphausia superba is a key species in the Southern Ocean that serves as a link between primary production and higher trophic levels. To investigate the feeding strategies of E. superba from the eastern South Shetland Islands,fatty acid biomarkers, stable isotope signatures, and an incubation experiment were conducted. The results of the incubation experiment proved that adult E. superba mainly fed on 2–20 μm particles, demonstrating the importance of nanoplankton in their diet. Moreover, significant positive relationships between δ15 N and body size demonstrated that size-related dietary shifts were present in E. superba. Evidence from principal component analysis and the C16:1ω7/C18:4ω3 ratio showed that juveniles preferentially fed on dinoflagellates and adults were more likely to feed on diatoms. Fatty acid profiles in adult E. superba roughly mirrored the different trophic conditions and feeding strategies between stations. Adult E. superba at Stas D2-07, D5-07, DA-01 and DA-02 exhibited elevated levels of C16:1ω7, C18:4ω3, C18:1ω9 and C18:1ω9/C18:1ω7, indicating higher levels of feeding on both phytoplankton and higher trophic diets. In contrast, adult E. superba at Stas D1-03 and D1-04 were characterized by high levels of polyunsaturated fatty acids/saturated fatty acids ratios and low levels of C16:1ω7,C18:1ω7, C18:4ω3, C18:1ω9 and total fatty acids. We inferred that adult krill at Stas D1-03 and D1-04 still suffered from difficult dietary conditions after overwintering. The different dietary conditions between stations suggest a highly plastic feeding strategy of E. superba in the eastern South Shetland Islands.     

EES-GIS系统及其在九江-瑞昌地震中的应用

叙述了EES—GIS应急数据库系统的技术思路、组成及其功能,介绍了该系统在九江地震应急中的应用效果。实践表明,EES—GIS系统在地震应急辅助决策中能有效地提高评估效率。     

揭秘地质历史时期最大碳同位素负偏事件的本质

<正>碳循环通过大气-海洋的酸碱及氧化还原过程对地球表层化学环境起着关键控制作用,是地球表层环境演化的“发动机”.因而,弄清地球碳循环演化对于理解地球宜居性演化至关重要.作为地球宜居性演化过程中由前寒武纪向显生宙-现代地球系统转变的关键期,埃迪卡拉纪(635～539Ma)在全球范围内发生了地质历史上最大的一次沉积碳酸盐碳同位素组成(δ¹³C_carb)的负偏事件,     

华北陆块北缘尚义地区下井-厂汉营韧性剪切带变形特征及年代学研究

华北陆块北缘晚古生代经历了多期构造事件,构造活动复杂多样,位于其中段的下井-厂汉营韧性剪切带构造变形强烈,研究其变形特征以及形成时代,对进一步探讨华北陆块北缘晚古生代构造演化特别是古亚洲洋晚阶段洋壳俯冲的时间和机制有重要意义.鉴于此,对该韧性剪切带进行了运动学和几何学实测剖面、显微构造解析及锆石LA-ICP-MS U-...     

一种基于波浪能的海洋立体观测系统及应用

随着海洋波浪能发电技术的发展和成熟,其在海洋观测领域的应用受到关注和研究。自主设计并研制了一种集波浪能发电、海表/海底同步观测、实时4G 通信传输、远程无线控制于一体的海洋立体观测系统,于2021 年7 月在珠江口万山岛海域通过锚泊系留方式布放,开展海上波浪能供电和观测应用试验。海试期间连续获取了海底原位观测视频数据,以及海表波浪变化和波浪能发电参数等监测数据,并对波浪能发电电流、电压和功率进行了统计分析,讨论了波浪能发电水平受波浪变化的影响,分析了两者之间的相关性。试验结果表明：利用波浪能供电的海洋观测系统具备连续、长周期、全天候观测的优势和潜力,源源不断的波浪能可保障海洋观测系统的稳定观测和数据可靠传输,实现了海洋观测系统长期独立运行所需的绿色高效供能,验证了波浪能在海洋观测领域应用的可行性和先进性。     

化子坪长6储层长岩心CO2驱替实验及数值模拟评价

二氧化碳驱提高石油采收率(CO2-EOR)在我国大部分低渗透、低孔隙度油藏中的应用越来越重要。鉴于国家净零排放目标, 在采用二氧化碳驱提高采收率时, 二氧化碳封存是另一个重要考虑因素。针对低渗油藏, 开展天然岩心长岩心CO2驱替试验, 并利用TOGA(TOUGH Oil, Gas, Aqueous)软件建立岩心尺度数值模型开展模型的识别与验证, 对模型的有效性及物性参数进行敏感性分析, 结果表明, 1)根据出口气油比可将二氧化碳驱油与封存划分为未见气(0~100)、极少量气(100~1 000)、气体突破(1 000~10 000)、大量气窜(＞10 000)四个不同阶段; 2)孔隙度、渗透率及非均质性对模拟结果影响较大, 在后续实际场地模型中应予以重点关注。研究结果可为实际场地规模模型提供参数依据。     

青藏高原地区总辐射超太阳常数的观测研究

为了研究青藏高原地区（以拉萨站为代表）太阳总辐射的变化情况,分别使用常规观测站资料和自动观测站资料。常规观测资料使用的是逐日太阳最大总辐射以及出现太阳最大总辐射的时刻。１９９３年开始实施的中日亚洲季风研究市场调节太阳总辐射是敏隔２０ｍｉｎ采集一次。基于上述资料研究发现有青藏高原太阳总辐射大于太阳的反常现象。并对这种反常现象进行了统计,得到了一些有意义的结果,最后在非局域力学平衡（ＮＬＴＥ）假设下,     

金龙山-丘岭金矿床地质地球化学特征及成因:秦岭式卡林型金矿成矿动力学机制

秦岭卡林型金矿带是世界第２大卡林型金矿集中区,与形成于新生代活动大 陆边缘盆岭省的美国西部卡林型金矿不同,产于中生代大陆内部碰撞造山带,成矿同 位素年龄集中于 １９７．４５－１２９．４５ Ｍａ,属碰撞造山挤压伸展转变期的减压增温体制,表明成矿与碰撞同步．包裹体、同位素和成矿元素地球化学研究揭示成矿流体和成矿物质主要来自海西－印支构造层,中生代时海西－印支构造层沿双河－公馆断裂等的陆内俯冲导 致了金龙山等金矿床形成,基此建立了“秦岭式”卡林型金矿构造成矿模式．     

LICOM模拟的南海贯穿流及其对南海上层热含量的影响

利用SODA(Simple Ocean Data Assimilation)数据、XBT(Expendable Bathythermograph)观测数据和绕岛环流理论(island rule)诊断计算结果评估了一个涡相容(eddy-permitting)全球海洋环流模式——LICOM对南海贯穿流及南海上层热含量的模拟能力,同时利用模式输出探讨了南海贯穿流对南海上层热含量的影响。NEC(North Equatorial Current)分叉的垂向结构、南海内区环流的季节和吕宋海峡体积输送的年际变化等分析结果都表明,LICOM能获取西北太平洋-印尼海域环流和南海贯穿流的合理模拟结果。模式模拟的南海上层热含量季节变化与观测及同化数据都表现出良好的一致性,尤其在南海内区。相关分析表明,吕宋海峡热输送主要控制着南海内区上层的热含量变化,两者呈显著负相关,这进一步证实了南海贯穿流作为一支冷平流调制着南海上层热含量变化的重要事实。