Overview on seagrasses and related research in China

Seagrass research in China is still in its infancy. Even though there has been progress recently, there is still a great deal of research needed to gain a better understanding of seagrass. In this article we review and discuss the advances in seagrass research in China from two aspects: (1) seagrass species and their distribution; (2) seagrass research in China, including studies on their taxonomy, ecology, photosynthesis, applications in aquaculture, salt-tolerance mechanisms and other research topics. A total of 18 seagrass species belonging to 8 genera are distributed in nine provinces and regions in China (including Hong Kong and Taiwan), as well as the Xisha and Nansha Archipelagos. They can be divided into two groups: a North China Group and a South China Group. Based on the seagrass distribution, the Chinese mainland coast can be divided into three sections: North China Seagrass Coast, Middle China Seagrass Coast, and South China Seagrass Coast. Ecological studies include research on seagrass communities, nutrient cycling in seagrass ecosystems, genetic diversity, pollution ecology and research in the key regions of Shandong, Guangdong, Guangxi, and Hainan. Seagrass species and their locations, community structure, ecological evaluation, epiphytes, ecological functions and threats in the key regions are also summarized. Other studies have focused on remote sensing of seagrass, threatened seagrass species of China, and pollen morphology of Halophila ovalis.     

Erratum to: Automatic calibration for wobble errors in shallow water multibeam bathymetries

Journal of Oceanology and Limnology -     

赤潮生物种类特征光谱获取技术

较为系统地研究了赤潮生物水体反射率曲线获取方法。通过对 2类反射率反演方法得出的反射率曲线与实际反射率曲线进行比较 ,得出在不具备大气环境参数的情况下 ,经验线性法的反演结果与实际反射率曲线最接近的结论 ,并进一步对正常海水和赤潮生物水体的光谱特性进行分析 ,提取出赤潮生物水体的特征光谱。这是进行赤潮监测和识别的重要前提     

Molecular fossil and paleovegetation records of paleosol S4 and adjacent loess layers in the Luochuan loess section, NW China

Using gas chromatography-mass spectrometry (GC-MS) technique, a series of biomarkers were identi- fied, including n-alkanes, n-alkane-2-ones, isoprenoid etc. from the loess-paleosol samples collected from the S4 and adjacent L5, L4 of the Luochuan loess section, Northwestern China. Based on these data, especially n-alkanes and high-resolution magnetic susceptibility and grain size data, the pa- leoenvironment and paleovegetation history during S4 was reconstructed. The CPI (Carbon Predomi- nance Index) and correlation between n-alkanes and magnetic susceptibility and grain size data dem- onstrated that the molecular fossils in paleosol and loess layers can reflect the vegetation condition during the loess-paleosol formation, if the allochthonous organic inputs could be excluded reasonably. The ACL (average chain length) index is correlated well with paleomagnetic susceptibility and grain size variations, displaying their good synchrony with warm and humid climate. However, it relatively lagged behind the paleomagnetic susceptibility and the grain size variations when the climate began to deteriorate. During the formation period of paleosol, the n-alkanes was dominated by C31 homologue, indicating that the primary organic input originated from herbs. Our study also demonstrated that the herbs were more flourish than wood plants in Loess Plateau, especially in the Luochuan area during the warm and humid phase, and there was no typical forest vegetation developed in the studied period.     

不同形式的断层土壤气集气装置对气氡观测结果影响的实验研究

任何一项观测都要在一定的条件下进行,不同的观测条件会产生不同的观测结果。在断层土壤气实际观测中,由于观测装置的集气室安装方式不同形成了不同形式的集气装置,而不同形式的集气装置会对气氡观测结果产生不同影响。本文就不同形式的断层土壤气集气装置对气氡观测结果的影响进行了实验研究。结果表明,集气室滞留体积对观测结果影响较大,集气室不可保留滞留体积,应控制导气管的长度和粗细,尽量减少导气管产生的滞留体积对观测结果造成影响。集气室死体积对观测结果影响不大,可保留集气室死体积。模拟观测和数字化观测应使用不同模式的集气装置。     

东北地区降水与大气环流关系

利用Lamb-Jenkinson大气环流分型方法, 将1951—2004年逐日的海平面气压场分型, 得到27种不同的环流型, 研究了大气环流型与我国东北地区降水的关系。给出了8种出现频率最高的主要环流型出现的规律及它们平均的环流形势, 分析了8种主要环流型下东北地区降水异常分布状况, 并选出东北地区资料齐全、有代表性的9个站点进行了深入细致地分析, 成功地建立了降水与环流型出现频率的统计关系, 并用此重建了9个代表站54年的降水序列。结果表明:Lamb-Jenkinson大气环流分型方法可以很好地应用于我国东北地区, 由此划分的环流型符合实际情况; 8种主要环流型与降水的空间分布特征有很好的对应关系; 所建立的9个代表站降水距平回归方程能够解释近54年各站的大部分降水变化, 进一步证明了东北地区降水与大气环流之间的密切关系。     

华北强震地形变及重力前兆特征与孕震机理

通过分析华北地区强震地形变及重务前兆特征,发现震前在较大范围内存在与构造密切相关的动力不过程;在震中区介质状态发生变化。在此基础上提出了改进的组合－硬化模式：调整单元的运动,牵动较大范围构造运动的加及断层两侧深层介质密度变化;应力集中单元由于能量的不断积累,介质出现硬化过程。上述机理形成了前兆的各个阶段。     

新的高原季风指数与四川盆地夏季降水的关系

用NCEP/NCAR逐月再分析资料和中国560站月降水资料,定义了一个高原季风指数IPM2。结果表明:与原有高原季风指数相比,该指数与四川盆地夏季降水的相关性更好,能够较好地反映四川盆地夏季降水的异常变化。当高原夏季风偏弱时,巴尔喀什湖至贝加尔湖低压槽、亚洲东岸高压脊、印度低压均加强,同时西太平洋副热带高压偏北,来自孟加拉湾的西南风水汽输送和源于西太平洋的偏南风水汽输送均加强,这种环流形式有利于四川盆地西(东)部夏季降水偏多(少);当高原夏季风偏强时,情况相反。IPM2弱(强)大(小)年与四川盆地西(东)部涝年环流背景相似,表明IPM2能够很好反映四川盆地夏季降水异常的环流场特征。     

Chemical indexes of Paleoproterozoic sedimentary rocks from Liaohe Group,North China Craton:Implications for paleoclimate and provenance

Paleoproterozoic supracrustal materials have been widely identified in North China Craton, such as the Liaohe-, Hutuo-and Lyuliang groups. The Liaohe Group in the eastern part of the North China Craton is dominated by deformed and metamorphosed sedimentary and volcanic successions. Compared with that of the coeval volcanic rocks, geochemistry of the sedimentary rocks from the Liaohe Group has rarely been studied in detail, which can possibly provide information on the paleoclimate and provenance. The authors analyzed the whole-rock and detrital zircon geochemistry of sedimentary rocks from the Liaohe Group against a uniform process and proposed their different ways of paleoweathering of the lower and upper formations. That is to say, although the lower and upper formations within the Liaohe Group might be derived from the similar source composition in a tectonically active setting, the paleoclimate that they experienced was not exactly the same. The predominant derivations are the Paleoproterozoic granitoids and basalts within the Liaohe Group, with minor input of Archean continental crust. This study highlights the contributions of the Paleoproterozoic mafic sources, which has been generally overlooked in the previous researches.     

基于光合有效辐射的西北太平洋柔鱼资源丰度和空间分布变动研究

光合有效辐射(PAR)对于海洋初级生产力具有显著的调控作用,会间接影响到头足类的资源丰度和渔场分布。本文根据2006−2015年上海海洋大学鱿钓科学技术组提供的柔鱼鱿钓数据和光合有效辐射卫星遥感数据,研究了光合有效辐射与西北太平洋柔鱼种群的关系,并评估了异常环境条件下光合有效辐射对柔鱼的影响。结果发现,柔鱼单位捕捞努力量渔获量(CPUE)、渔场纬度重心、PAR,及其空间分布均具有显著的月间变化。7−11月各月适宜PAR范围分别为36～39 E/(m²·d)、33～36 E/(m²·d)、24～27 E/(m²·d)、18 E/(m²·d)和12 E/(m²·d),最适宜PAR值分别为36 E/(m²·d)、33 E/(m²·d)、27 E/(m²·d)、18 E/(m²·d)和12 E/(m²·d)。此外,CPUE与PAR有显著正相关关系(p<0.05),且CPUE与各月适宜PAR范围占渔场比例也呈显著正相关(p<0.05);同时渔场纬度重心随各月最适PAR平均纬度变化而变化。在异常环境条件下,拉尼娜年份CPUE值比厄尔尼诺年份高,该年份PAR值异常增高可能是导致柔鱼资源丰度增加的因素之一。研究表明,光合有效辐射对于西北太平洋柔鱼资源丰度和空间分布具有显著影响。