Short‐term temporal variation in gelatinous zooplankton populations over 48 hours in a coral reef at Redang Island,Malaysia

Gelatinous zooplankton abundance and species composition were investigated at 3‐h intervals for a 48‐h period at a fringing reef in Malaysia. A total of 20 gelatinous zooplankton species were observed; the community was dominated by the calycophoran siphonophore Diphyes chamissonis (79.9%), followed by the trachymedusdae Aglaura hemistoma (5.6%) and Liriope tetraphylla (4.8%). The gelatinous zooplankton were not collected in the water column during most of the daytime hours (1200, 1500 and 1800 h) but were common during the night. However, an abrupt peak in abundance was found at 0900 h on the second day. The times of appearance at night were different depending on the species, and the number of species was also different depending on the hour of sampling. Sampling at 3‐h intervals over a 48‐h period revealed that the temporal variation (or sampling availability) was large in this study. Careful consideration should be given to the sampling variability in handling the gelatinous zooplankton samples in coral reef areas.     

夏季降雨事件对水库温室气体通量变化的影响:来自湖北官庄水库的高频观测

湖库淡水水域对温室气体排放的贡献不容小觑,然而观测时间的代表性不足以及缺乏对降雨因素的考虑制约了碳排放的准确估计.本研究以湖北宜昌境内官庄水库为例,选取强降雨多发的夏季时段,针对水气界面温室气体通量、水体表层和垂向剖面气体溶存浓度及环境因子开展了为期1周的原位高频观测,以探讨夏季降雨事件对水库温室气体通量变化的影响.结果表明,观测期内官庄水库水气界面CH₄通量变化范围为0.007~0.077 mg/（m²·h）,CO₂通量范围为5.48~57.57 mg/（m²·h）,白天和夜晚均表现为大气的碳源.小雨、中雨乃至暴雨天气条件下,CH₄和CO₂日均通量均较低,日通量倾向于受风速和温度调控.CH₄和CO₂通量变化趋势较为一致,观测期内日间排放量高于夜间排放量出现的次数更多,昼夜差异对降雨天气状况无明显响应,风速是CH₄和CO₂通量昼夜变化的主导因素.暴雨过程中,CH₄-k₆₀₀和CO₂-k₆₀₀与水气温差存在显著正相关,但水体垂向混合过程十分短暂.在平均雨强为3.8 mm/h的暴雨第I阶段,CH₄-k₆₀₀对风速和降雨的响应明显,而在雨强更大（8.5 mm/h）的第II阶段,CH₄-k₆₀₀与风速、降雨均未表现出相关性,通量箱在强降雨条件下的适用性可能存在雨强阈值.     

南盘江盆地中三叠统复理石韵律的马尔科夫链特征及其地质意义

本文利用南盘江盆地中三叠统复理石韵律的野外测量数据,从马尔柯夫链原理出发,对其进行了频数转移矩阵、概率转移矩阵、极限概率矩阵和环流矩阵等沉积旋回最优分解综合分析.分析过程中发现并命名了循环链和二级循环链,并对循环链进行了特殊处理.通过分析模拟获得的状态循环模式图,建立了不同地点实测段的代表性韵律结构模式并绘制了韵律结构...