Limnology of Opal Lake     

D. J. Forsyth  A. L. MacKenzie 《新西兰海洋与淡水研究杂志》2013,47(3):279-283

Opal Lake, a cold, acid lake on the central volcanic plateau of the North Island, New Zealand, had an average pH of 4.3 and was highly eutrophic. The biota was less diverse than in neighbouring near‐neutral waters. Macrophytes were rare; phytoplankton were mainly represented by the Chlorophyceae, and there were only 4 zooplankton species. The mean standing crop of macroinvertebrates was 6240 per square metre; this was higher than in other eutrophic lakes in the region and comprised more than 98% chironomid larvae represented by 4 species. Molluscs were absent. The fauna was more diverse than in more acid lakes of the .central volcanic plateau.  相似文献   

东太湖不同水域浮游生物周年变化及鲢、鳙食性的研究   总被引：1，自引：0，他引：1  

李倩倩  黄鹤忠  张群英  王小林  朱茂晓  沈振华  袁文成  陆建明 《海洋科学》2013,37(10):104-110

2012 年2～11 月对东太湖不同水域浮游生物组成、数量、水质情况及水生植物密度进行了调查, 并对9 月份太湖鲢、鳙的食性进行了研究。结果表明: 浮游动物和浮游植物多样性指数均为保护区＞余山＞老鼠山＞漫山岛。水体浮游生物数量和综合营养状态指数均为漫山岛＞老鼠山＞余山＞保护区。浮游植物总数量与蓝藻总数量、浮游动物总数量、富营养化因子呈正相关, 与水生植物密度呈负相关。9 月份太湖鲢、鳙的肠内含物中浮游植物和浮游动物分别占食物数量的89.1%、70.6%和10.9%、29.4%,其中蓝藻分别占74.5%、56%, 枝角类和轮虫分别占3.7%、13.4%和1.5%、11.5%; 鲢、鳙对蓝藻的选择性指数分别为1.42 和1.07, 对轮虫和原生动物的选择性指数分别为0.13、1.27 和1.30、0.40。本研究结果对揭示影响太湖浮游生物周年变化的环境因素以及通过鲢、鳙控制蓝藻具有一定的理论价值和指导意义。  相似文献   

Diet of landlocked sockeye salmon (Oncorhynchus nerka) and trout in the Waitaki lakes,New Zealand     

E. Graynoth  L. C. Bennett  J. C. Pollard 《新西兰海洋与淡水研究杂志》2013,47(4):537-549

Landlocked sockeye salmon (Oncorhynchus nerka), ranging in fork length (FL) from 105 to 313 mm, were captured in fine‐mesh gill nets set in the limnetic zone of the Waitaki hydro lakes (44° 30′ S, 170° 10’ E) in the South Island, New Zealand. A total of 443 stomachs was examined and the frequency of occurrence, volume and weight of prey items calculated. In the Ahuriri Arm of Lake Benmore the principal food (54% by weight) was zooplankton (Boeckella dilatata) whereas in the Haldon Arm of Lake Benmore it was larval and juvenile common bullies (Gobiomorphus cotidi‐anus) (73% by volume). In Lake Waitaki in winter, salmon had eaten insects (43% by volume) with smaller amounts of snails (Potamopyrgus antipo‐darum, 23%) and bullies (24%). In Lake Ohau adult insects may be an important food. There were also variations in diet with season and fish size. The stomachs of 147 brown trout (Salmo trutta) and 181 rainbow trout (S. gairdnerii) caught in the same gill nets were also examined. In contrast to sockeye salmon stomachs they contained negligible amounts of zooplankton (< 1% by weight) and large amounts of aquatic insects (50–58% by weight in the Ahuriri Arm of Lake Benmore). Comparisons with juvenile sockeye salmon and kokanee in North American lakes are made. The impact of introductions of sockeye salmon into other New Zealand lakes is discussed.  相似文献   

Food and energy in the diet of brown and rainbow trout from Lake Benmore,New Zealand     

N. H. McCarter 《新西兰海洋与淡水研究杂志》2013,47(4):551-559

The diet of brown trout (Salmo trutta) and rainbow trout (S. gairdnerii) was studied in specimens from Lake Benmore, a deep, oligo‐trophic lake in South Island, New Zealand. Between November and July, both species fed mainly on small molluscs (Potamopyrgus antipodarum, Physa sp., and Gyraulus corinna) gleaned from the littoral weed beds. Energy values for the three species of mollusc were determined: P. antipodarum, 6000 J g^‐1; G. corinna, 5500 J g^‐1; Physa sp., 9800 J g^‐1. Potamopyrgus antipodarum yielded little energy to the fish, unless its shell broke during passage through the gut. Physa sp. was the most profitable mollusc, irrespective of shell breakage and Potamopyrgus antipodanim the least profitable. The mean energy value per snail for G. corinna and Physa sp. eaten by rainbow trout was 25–30% less than for snails eaten by brown trout, possibly because rainbow trout ingested empty shells from the sediment surface. Rainbow trout extracted about 20% more energy than brown trout from unbroken shells. In July, 84% of the brown trout switched to predation of common bullies, Gobio‐morphus cotidianus, probably as a result of bully reproductive behaviour. Rainbow trout did not show the same change, apparently because they were feeding in deeper water where few bullies were available. The low‐energy diet and its possible connection with growth rate are discussed.  相似文献   

长江中游城陵矶河段2016-2020年汛期水位非正常波动:影响因子及滤波修正     

程海云  香天元  唐聪 《湖泊科学》2022,34(1):286-295

长江经济带的人口和经济总量均超过全国的40％,长江中游城市群受地理位置与水文条件的综合影响更易遭受洪涝灾害的威胁.莲花塘水位站作为长江中游城陵矶河段蓄滞洪区启用指标控制站,当三峡水库水位达155.0 m后,如莲花塘站水位达到34.40 m并继续上涨,则城陵矶附近区蓄滞洪区需采取分洪措施.然而受河流形态和江湖关系(长江与...  相似文献   

黄河源鄂陵湖地区辐射收支和地表能量平衡特征研究     

唐恬  王磊  文小航 《冰川冻土》2013,35(6):1462-1473

利用2010年6-7月鄂陵湖野外试验的近地层观测数据,分析了在不同天气条件下黄河源鄂陵湖地区辐射分量、地表能量分量、土壤温度和反照率的变化特征. 结果表明：不同天气条件下,辐射和地表能量各分量日变化差异较大,晴天、阴天和雨天的地表反照率依次递减,平均反照率约为0.21;观测期内,平均辐射贡献从大到小依次为向上长波、向下长波、向下短波、向上短波,日积分值分别为31.4 MJ·m^-2、25.6 MJ·m^-2、22.4 MJ·m^-2、4.2 MJ·m^-2,净辐射(12.5 MJ·m^-2)占向下短波辐射的55.7%;平均地表能量和土壤温度的变化幅度较晴天小,感热、潜热、0 cm土壤热通量的平均日积分值分别占净辐射的21.2%、43.1%、8.2%;平均土壤温度变化幅度随深度增加逐渐减小,浅层土壤温度峰值较晴天低2 ℃,深层土壤温度相差不大. 云和降水的扰动削弱了向下短波辐射,导致平均感热通量和0 cm土壤热通量的峰值比晴天小,而平均潜热通量的峰值大于晴天. 由于湖泊水体巨大的热容量和水分供应,鄂陵湖地区的气温日较差较小,地表温度变化幅度变小,附近地表温度升高缓慢. 鄂陵湖区的地表能量平衡中,潜热通量占主导,感热和地表土壤热通量次之. 研究结果有助于理解气候变化背景下黄河源区湖泊的能量水分循环过程,为促进该地区光热资源的合理利用和畜牧业的可持续发展提供数据支持.  相似文献   

基于WRF模式数据和CASA模型的青海湖流域草地NPP估算研究   总被引：4，自引：1，他引：3  

郑中  祁元  潘小多  葛劲松  聂学敏 《冰川冻土》2013,35(2):465-474

植被净初级生产力(NPP)是研究陆地碳循环过程的核心内容, 而高海拔区域由于气象观测数据的缺乏造成模型对其估算的不准确.在WRF模式气象数据和SPOT-VEGETATION遥感影像的基础上, 利用CASA模型对青海湖流域2000-2010年的草地NPP进行了估算, 经过实地样方数据和其他模型数据的验证后, 分析了青海湖流域近11 a来草地NPP的空间分布格局和时间变化特征.结果表明: 1)在气象观测资料缺乏的青海湖流域, WRF模式的气象数据能较好地应用到模型中, CASA模型对该区域草地NPP的模拟精度较高; 2)2000-2010年青海湖流域草地年均NPP为2.71×10¹²gC·a^-1, 单位面积草地NPP为145.71 gC·m^-2·a^-1; 空间分布上呈现出由东南向西北随着海拔升高逐渐下降的格局, 在海拔3 200~3 500 m的区域草地单位面积的NPP达到最大; 3)2000-2010年青海湖流域草地NPP年际变化明显, 近11 a呈现出明显的增加趋势, 增加区域主要分布在环湖地区; 年内季节变化显著, 夏季NPP占到全年的57.36%; 4)对NPP和气象站点太阳辐射、 气温、 降水数据进行相关性分析, 发现影响青海湖流域草地NPP变化的主要驱动力是气温.  相似文献   

1960-2011年长江流域潜在蒸发量的时空变化特征   总被引：5，自引：2，他引：3  

郝振纯  杨荣榕  陈新美  陈玺  梁之豪  达娃顿珠 《冰川冻土》2013,35(2):408-419

以长江流域123个气象站1960-2011年逐日气象数据为基础, 应用Penman-Monteith模型, 在ArcGIS环境下通过IDW插值法、 TFPW-MK、 R/S等方法分析了全流域潜在蒸发量变化的时空变化、 趋势性和持续性, 并探讨了影响潜在蒸发量的主要气象因素.结果表明: 年潜在蒸发量自1960年以来至2002年呈波动减少趋势, 2003-2009年呈显著增加趋势, 整体为增加趋势; 其中, 上游高原区、 上游盆地区、 下游区年潜在蒸发量呈增加趋势, 中游区呈下降趋势, 增幅最大的是上游盆地区.四季中, 春、 夏、 秋季和年潜在蒸发量具有持续性, 未来将持续增加.最低气温、 最高气温是影响长江流域潜在蒸发量增加的主要因子.  相似文献   

Sediment modelling with fine temporal and spatial resolution for a hilly catchment   总被引：1，自引：0，他引：1  

A. H. Elliott  F. Oehler  J. Schmidt  J. C. Ekanayake 《水文研究》2012,26(24):3645-3660

The suitability of the physically based model SHETRAN for simulating sediment generation and delivery with a high degree of spatial (20 m) and temporal (sub‐hourly) resolution was assessed through application of the model to a 167‐km² catchment leading to an estuary in New Zealand. By subdividing the catchment and conducting calculations on a computer cluster for a 6‐month hydrology initialisation period, it was possible to simulate a large rainfall event and its antecedent conditions in 24 h of computation time. The model was calibrated satisfactorily to catchment outlet flow and sediment flux for a large rainfall event in two subcatchments (~2 km²). Validation for a separate subcatchment was successful for flow (Nash–Sutcliff efficiency of 0.84) with a factor 2.1 over‐prediction for sediment load. Validation for sediment at full catchment scale using parameters from the subcatchment scale was good for flow but poor for sediment, with gross under‐estimation of the dominant stream sources of sediment. After recalibration at catchment scale, validation for a separate event gave good results for flow (Nash–Sutcliff efficiency of 0.93) and sediment load within a factor of two of measurements. An exploratory spatially explicit landslide model was added to SHETRAN, but it was not possible to test this fully because no landslides were observed in the study period. Application to climate change highlighted the non‐linear response to extreme rainfall. However, full exploration of land use and climate change and the evaluation of uncertainty were severely constrained by computational limitations. Subdivision of the catchment with separate stream routing is suggested as a way forward to overcome these limitations. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

青海湖布哈河流域树轮宽度指数与NDVI植被指数的关系   总被引：4，自引：2，他引：2  

汪青春  时兴合  刘义花  秦宁生  邵雪梅 《冰川冻土》2012,34(6):1424-1432

利用来自青海湖流域乌兰和天峻的树轮指数和1982-2003年逐月标准化植被指数(NDVI)数据及气候数据, 在分析树轮指数及草地NDVI与气候因子关系的基础上, 探讨了树轮宽度指数序列与青海湖布哈河流域草地NDVI之间的关系.结果表明: 树轮宽度指数及草地NDVI主要受6-8月份的水热条件的影响, 温度与同期树轮宽度指数及草地NDVI具有较高的正相关, 而降水的影响存在滞后性.树木年轮指数序列与6-8月草地NDVI有显著的相关关系, 与8月份的NDVI相关性最强.树轮指数与草地NDVI间的显著相关性为研究该地区草地过去的动态变化提供了基础, 利用乌兰和天峻的两条树轮指数重建了8月份NDVI的千年变化.  相似文献