不同氮、磷浓度及配比对铜藻(Sargassum horneri)幼苗生长的影响

采用铜藻(Sargassum horneri)幼苗为实验对象,分别以Na NO3和Na H2PO4为氮源和磷源,研究了不同氮磷质量浓度及氮磷配比对铜藻幼苗生长的影响。进行了氮、磷单因子实验、双因子实验以及不同氮磷配比实验,实验时间为8d。结果表明:氮和磷对铜藻幼苗生长影响极显著(P0.01),且当氮、磷的质量浓度分别为8mg/L、0.4mg/L时,铜藻幼苗的特定生长率最大;交互作用影响不显著(P0.05),不同质量浓度的氮为主效应;不同氮磷质量浓度比影响极显著(P0.01),且当氮磷比为10:1时,铜藻幼苗的特定生长率最大。研究结果为铜藻幼苗培育过程中营养盐的合理调控提供了理论依据。     

南极普里兹湾海域湍流扩散系数估计

基于Thorpe尺度方法,利用CTD数据,计算了南极普里兹湾海域的Thorpe尺度和湍流扩散系数,分析了观测区域(64°～69°S,66°～80°E)湍流翻转现象的强弱及分布。结果表明,在海底和地形粗糙区存在较大的Thorpe尺度(较强湍流翻转)和湍流扩散系数,湍流扩散系数最大值能达到10^-2m²/s量级,比平坦开阔海洋高2～3个数量级,部分观测站位的湍流扩散系数和湍动能耗散率表现出大-小-大的垂向分布结构,总水深较深的区域尤为明显;深水区域的浮力频率在海表面到500 m层比较大,浅水区域该现象不明显;湍动能耗散率在(67.25°S,73°E)周围和经度为78°E的各站位都表现相对较大,能达到10^-6 w/kg量级,个别站位甚至能达到10^-5 w/kg量级。     

人工砾石海滩变化及输移率研究

在我国采用砾石海滩在某些强动力区域进行海滩养护是一种新的尝试,具有很好的适用性。以厦门天泉湾人工砾石滩为研究对象,对2015年至2016年间10条海滩剖面开展了5次周期性监测,通过综合分析,得出在人工砾石滩竣工完成后的一年时间内,滩肩外沿线、岸线及滩面底角的砂砾分界线大幅度后退,滩肩宽度变窄;滩肩外沿线明显隆起,形成滩肩脊线;滩面坡度变大,且上游侧海滩的滩面普遍比下游侧海滩的滩面陡,一年后,岸滩整体变化趋于稳定。针对砾石滩不断向西南方向运移的现状,采用Leo C.van Rijn输移率公式计算砾石滩年平均输移率,并通过测量断面法、体积变化量法对Leo C.van Rijn公式计算结果进行验证,得出砾石滩年平均输移率的范围约为1 015.66~2 392.5 m~3/a。     

珠江口海域春季富营养化现状与影响分析

随着珠江三角洲经济圈的迅速发展,珠江口海域环境污染日趋严重,于2014年春季对珠江口邻近海域进行环境现状调查,并通过因子分析法和聚类分析法就珠江口调查海域管辖城市和邻近区域的环境现状对珠江口海域环境污染的贡献率进行排序和分类.结果表明:珠江口调查海域营养盐污染较为严重,无机氮含量范围为0.213~1.963 mg/dm~3,平均值为0.888 mg/dm~3;活性磷酸盐含量范围为0.009~0.063 mg/dm~3,平均值为0.033 mg/dm~3.无机氮和活性磷酸盐在珠江口上游和中游均超过海水水质第四类标准,珠江口下游无机氮含量符合海水水质第四类标准,活性磷酸盐含量符合海水水质第二类标准.无机氮以硝氮为主,氨氮次之,亚硝氮含量最低.珠江口调查海域DIN/P变化范围为8.5~168.0,平均值为31.8;富营养化指数E变化范围为0.3~45.1,平均值为8.2,富营养化较为严重.来自广州、东莞、佛山、中山的四大口门排入的污染物对珠江口海域环境影响最大,其次是深圳西部海域沿岸和前海湾、深圳湾排入的污染物,最后是珠海、澳门和香港带入的污染物.从珠江口邻近海域环境现状对珠江口海域环境影响进行较为深入地分析和探讨,为珠江口海域环境的治理和修复提供一些意见和建议.     

pH值对单环刺螠呼吸排泄的影响

为研究pH值对单环刺螠(Urechis unicinctus)呼吸排泄的影响,采用静水密封法,研究了不同pH值(5、6、7、8、9)对体质量5.65±1.06g单环刺螠耗氧率、排氨率、能量代谢率、O/N值的影响.结果表明,pH值对单环刺螠耗氧率、排氨率、能量代谢率、O/N值均有显著影响(p0.05).单环刺螠耗氧率随pH值的升高而增大,pH值为8时达到最大值,之后随pH值的升高而减小.单环刺螠耗氧率与pH值之间的拟合方程为:OR=-2.977X2+55.188X-176.380,R2=0.937.单环刺螠排氨率的变化与耗氧率相似,在pH值为7时排氨率达到最大值;pH值为9时排氨率最小,与pH值为8的组差异不显著(p0.05).排氨率与pH值之间的拟合方程为:NR=-0.350X2+4.442X-6.822,R2=0.724.单环刺螠能量代谢率、O/N值均随pH值的升高呈先增大后减小的趋势,拟合方程分别为:M=-0.040X2+0.424X-0.044,R2=0.937;A=0.053X2+1.879X-7.470,R2=0.901.pH值为8的环境中,单环刺螠体内蛋白质代谢水平最低,有利于蛋白质的积累.研究表明,单环刺螠在一定pH值范围内可以通过调整生理代谢水平适应水体pH值,其适宜生活在弱碱性水中,生存最适pH值为8.     

Analysis of bycatch in the South African midwater trawl fishery for horse mackerel Trachurus capensis based on observer data

The South African midwater trawl fishery targets adult horse mackerel Trachurus capensis. The bulk of the catch is taken by a single freezer-trawler, the biggest fishing vessel operating in South African waters. As fishing takes place off the south coast in ecologically sensitive areas, there are concerns about the potential impacts of this fishing operation on non-target species. Fishing behaviour and bycatch of this fishery from 2004 to 2014 were investigated by analysing observer records with regard to catch composition, volume and temporal and spatial patterns. The midwater trawl fishery was estimated to have caught 25 415 tonnes annually, with a bycatch of 6.9% of the total catch, by weight. There are species overlaps with various fisheries, namely the demersal trawl, small-pelagic, line, shark longline and squid fisheries, yet the total bycatch estimates from this fishery are generally small relative to catches taken in the target fisheries. Bycatch species with the highest average annual catches were chub mackerel Scomber japonicus, redeye roundherring Etrumeus whiteheadi, ribbonfish Lepidopus caudatus and hake Merluccius spp. Large-fauna bycatch species included sunfish Mola mola as well as a number of CITES II- and IUCN-listed species, such as Cape fur seal Arctocephalus pusillus, dusky shark Carcharhinus obscurus, smooth hammerhead shark Sphyrna zygaena and thresher sharks Alopias spp. The 97.9% observer coverage is high and the 6.9% bycatch rate low compared to other South African fisheries; however, due to the large size of the individual hauls (average of 46.3 t), the average sampling rate of 1.56% is low. Our analyses suggest that bycatch in the South African midwater trawl fishery has been lower than in other South African fisheries and similar fisheries elsewhere, but due to the combination of high catch volumes and low sampling rates, estimation errors for rare species are high and there is a substantial risk of incidental unmonitored bycatch of rare large fauna and aggregations of small fauna. This could be mitigated by spatio-temporal management of this fishery, to avoid fishing in high-risk areas, and the introduction of an electronic monitoring programme.     

Population structure of the sicklefin lemon shark Negaprion acutidens within the Curieuse Marine National Park,Seychelles

This study produced the first data on population parameters for sicklefin lemon shark Negaprion acutidens at the granitic Seychelles Islands, adding to a limited catalogue of species information. Juveniles at a site in the Curieuse Marine National Park were tagged over two periods, in 2014–2015 and 2015–2016, with measurements of length (precaudal, fork and total) and weight, sex, and state of the umbilical opening recorded. Recapture data were used to calculate growth rates and population size. Mean annual growth rate was 5.40 cm y^–1. A mean size at birth of 62.5 cm TL is in line with previous assessments of the species. Population-size estimates were similar for the two sampling periods (comprising 311 and 255 individuals) and higher than anticipated. Movements to outside the lagoon were recorded for early ages, and this, combined with weight loss and a reduction in condition factor as displayed in several individuals, suggests that the study area alone could not support the large number of sharks pupped yearly.     

陕西泾阳南塬滑坡干湿黄土快速大剪切力学特性

借助于先进的多功能大型高速高压环剪试验机,针对陕西泾阳南塬滑坡中的饱和黄土、干燥黄土在快速大剪切位移条件下的力学响应特性进行了环剪试验研究。研究结果表明:1)在相同试验条件下,与干燥状态黄土相比,泾阳南塬黄土在饱和条件下抗剪强度指标降低。2)在连续快速剪切条件下,泾阳南塬滑坡饱和与干燥黄土均表现出应变软化特征,饱和黄土比干燥黄土的软化特征更加显著。3)在相同法向应力条件下,剪切速率对饱和和干燥黄土峰值强度均有显著影响,但两种状态下土体峰值强度随剪切速率变化特征不同。饱和黄土峰值强度随剪切速率的增大而增大,而干燥黄土峰值强度随剪切速率的增大而减小。4)在不同含水状态下,泾阳南塬滑坡黄土剪切力学特性变化规律具有不同的产生机理。其中,干燥黄土抗剪强度在连续剪切过程中主要受黏土颗粒间摩擦(阻)力、颗粒运移与定向排列以及剪切面形态的控制。与干燥黄土相比,饱和黄土峰值抗剪强度变化主要受土黏聚力的控制并受水的影响;土体内水的作用能够加剧其应变软化程度并可形成光滑平整的剪切面形态,进而对其峰后剪切应力变化产生影响。     

维嘉海山沉积过程及其对西太平洋海山演化的意义

海山沉积过程与全球气候变化和古海洋演化有着紧密联系,维嘉海山保留了西太平洋晚中生代以来的完整沉积记录,是探索西太平洋海山构造演化的理想场所.基于浅地层剖面、大洋钻探和最新相关研究成果,通过研究海山的沉积特征、火山活动和沉降速率等,探索西太平洋维嘉海山晚中生代以来的沉积过程.结果显示维嘉海山顶部发育3个沉积单元,并发现了...     

中国天山积雪对气候变化响应的多通径分析

基于天山山区1961-2013年60个气象站点实测气温、降水、相对湿度、日照时数和积雪深度等气候资料,结合时间序列分析、空间分析以及通径分析等方法,全面精确地获取了天山山区气候变化特征以及气候变化对积雪的通径影响。结果表明：天山山区气候变化显著,主要表现为整体增暖、局部变湿与黯化;气候变暖导致天山山区固态降水（降雪）保证率明显降低,尤其是低海拔区域。各气象要素对积雪不仅存在直接的单因素影响而且各气象要素之间还存在间接的相互交叉、相互联结的多因素影响。单因素影响通径分别为气温、降水和日照时数对积雪深度的3条直接影响通径;多因素影响通径分别为气温、降水和日照时数通过相互之间的内在关系对积雪深度产生的6条间接影响通径。最终结果表明气温是积雪变化的主要影响因素,其影响效应远远大于降水和日照时数的影响。