基于鱼类栖息地需求的雅鲁藏布江中游环境流量计算

针对水利工程影响下,河道下游天然水文情势改变造成鱼类产卵场面积减小和质量降低等潜在生态问题,通过数值模拟与统计建立拉萨裸裂尻鱼产卵期栖息地适宜度模型,采用栖息地模拟法计算了雅鲁藏布江中游藏木水电站坝下米林—尼洋河汇口处38.9 km河段的环境流量。结果表明:拉萨裸裂尻鱼产卵期适宜水深为0.7～1.0 m,适宜流速为0.4～0.6 m/s;研究河段内拉萨裸裂尻鱼产卵期环境流量为432 m~3/s。     

水温对竖缝式鱼道中齐口裂腹鱼上溯行为影响试验研究

水温是影响鱼类上溯行为不可忽视的因素之一,本研究在竖缝式鱼道水工模型中进行了齐口裂腹鱼幼鱼的过鱼试验,研究的水温变化范围为13～21℃,通过提取通过率与通过时间参数对齐口裂腹鱼的上溯行为进行了定量分析,并采用统计分析软件SPSS进行了检验.研究发现在开展试验的水温范围内,水温对齐口裂腹鱼上溯行有显著影响(P=0.032...     

基于模糊逻辑的裂腹鱼幼鱼生境适宜度指数分析

通过模糊逻辑的方法建立了雅砻江裂腹鱼幼鱼时期的生境适宜度指数模型。根据野外调查和室内实验结果,结合有经验的鱼类学专家的模糊知识建立了关于生境因子和幼鱼生境适宜度模糊集合的隶属度函数和模糊推理规则。模糊集合根据水温、流速和溶解氧3个变量因子,以“if-then”的规则语句实现了生境特性和适宜度的联系。根据模型分析,得出溶解氧是裂腹鱼幼鱼重要的生境因子,其次是温度和流速。单因子变化引起的相对极端环境对鱼类适宜度有显著影响。裂腹鱼对水温、溶解氧和流速的最适范围分别为11 ℃~19 ℃,5.75~10 mg/L和0.1~0.65 m/s。     

鲤鱼胚胎发育与温度和溶氧的关系

试验模拟了黄河径流条件(温度和溶氧)对黄河表征性鱼类——鲤鱼受精卵发育的影响。结果表明:鲤鱼受精卵发育与温度和溶氧关系密切。在设置的温度梯度内(16℃,20℃,24℃,28℃),鲤鱼受精卵出膜时间与水温呈负相关,孵化的合适水温范围为20℃～24℃,孵化率较高(64.43%～76.97%)。水体中溶氧较为充足时,约6.28mg/l～6.75mg/l,鲤鱼胚胎正常发育。不同溶氧浓度对受精卵发育影响差异不明显,但当水体中溶氧不足时(约小于5.01mg/l),则严重影响鲤鱼受精卵正常孵化。     

水温因素对竖缝式鱼道中草鱼上溯行为影响的试验

利用鱼道试验模型进行过鱼试验, 分析水温因素对模型鱼道中鱼类上溯行为的影响。以某工程竖缝式鱼道为原型, 按重力相似准则建立比尺为 1：4 的水工模型, 选择草鱼幼鱼为试验用鱼, 试验中采用摄像头全程监测试验鱼上溯过程, 统计试验鱼在模型试验段的通过率与通过时间两项指标, 进行量化分析。研究发现: 在试验水温变化范 围 18.5~ 22. 5 ℃内, 草鱼幼鱼总体通过率达 70% 以上, 且不同水温区间内通过率无明显变化; 采用 SPSS 软件进行的显著性检验显示, 草鱼通过时间与水温因素无显著相关关系。基于上述结果, 今后在开展草鱼上溯行为试验研究时, 在水温变化范围 18.5~ 22.5 ℃ 内, 可考虑忽略水温因素的影响。     

双污泥回流A~2/O工艺在低温下的脱氮除磷效果

在温度为9~16℃的低温条件下,考察了双污泥回流A2/O工艺系统处理低C/N城市污水的脱氮除磷特性。试验结果表明:在低温处理低C/N城市污水时,将A2/O工艺改良为双污泥回流系统,通过富集反硝化除磷菌(DPB)和强化缺氧吸磷等方法,取得了良好的同步脱氮除磷效果。当水温为12~16℃,缺氧池DO为0.2~0.4mg/L时,进水TN、NH3—N和TP平均分别为47.44mg/L、37.50mg/L和6.01mg/L时,系统出水TN、NH3—N和TP平均分别为12.81mg/L、2.75mg/L和0.37mg/L,去除率分别为72.99%、92.66%和93.90%,当水温为9~12℃时,系统对TN、NH3—N和TP去除效果下降,不能达到预定的去除目标。系统对COD去除效果良好,进水COD平均为253.59mg/L,出水为26.85mg/L,平均去除率为89.41%。     

低水温条件下饮用水处理工艺超滤膜中试研究

超滤膜过滤是提升饮用水水质的有效手段,但在我国高纬度(低水温)地区的应用仍然十分匮乏。多家企业参与的超滤膜中试结果表明,以传统砂滤池出水为原水,膜过滤出水的浊度能基本维持在0.1NTU左右。膜过滤出水中颗粒物数受所使用的超滤膜产品的性能影响很大,其中大于3μm的颗粒物数中位数为6～900个/mL。若采用压力式过滤方式,即便水温低至1℃,多数膜组件的膜过滤通量能维持在55～75L/(m2·h)。膜污染速率与超滤膜特性关联很大,不同超滤膜产品之间可以相差1个数量级(或以上)。     

微生物法地下水除锰经验点滴

保加利亚的 Danube、Mariyza 和 Tundja 等河流阶地地下水含 Mn~(2+)达3mg/L,同时还含铁、亚硝酸盐和硫化氢。并常有锰氧化菌存在。从1982年起开始研究用微生物法除锰,试验分别在水源地和处理厂进行。水源地试验:原水水质如下,水温8～25℃,pH 6.9～7.3,DO 0.1～2.2mg/L,锰1.0～1.25mg/L,铁0.2mg/L,氨氮0.4 mg/L,游离CO_2 8～14 mg/L,磷酸盐约0.02～0.04 mg/L,硫化氢0.4 mg/L,硝酸盐4～5 mg/     

Pb2+、Cu2+在黄颡鱼性腺中的富集及其对性腺发育的胁迫

研究Pb2+、Cu2+在其不同质量浓度(0.10 mg/L、0.25 mg/L、0.50 mg/L)情况下在黄颡鱼性腺中的富集特性以及对性腺发育的影响。结果表明,黄颡鱼性腺(卵巢)对Pb2+、Cu2+有较强的富集能力,在暴露期间的20—30 d内,Pb2+、Cu2+在性腺内的富集量分别与时间呈线性关系,之后呈对数关系。其中,Cu2+的富集显著大于Pb2+(P<0.01);性腺中的重金属富集与水溶液中Pb2+、Cu2+的浓度相关(P<0.01),具有明显的时间效应和剂量效应。黄颡鱼性腺细胞的发育水平,亦与溶液Pb2+、Cu2+的浓度与暴露时间相关。     

向家坝水电站下游水温变化分析

为明确溪洛渡—向家坝水电站联合运行对下游河道水温的影响,基于向家坝下游主要水文站长序列水温监测资料、电站蓄水资料,对向家坝下游河段水温变化趋势和河段梯级建设水温影响进行了统计分析。结果表明,溪洛渡、向家坝联合运行使向家坝站水温4月~9月降低了0.4~1.8℃,11月~次年1月升高了1.2~2.2℃;升温期朱沱站—华弹站水温温差降低了0.2~1.0℃,寸滩站—华弹站水温温差降低了0.4~0.7℃,其余月份均无明显变化。可见,该影响虽可延续至三峡库尾寸滩站,但已有明显削弱。     

青藏高原典型河流与湖泊表层水体碳时空变化特征初步分析

为了研究青藏高原典型河流与湖泊水体碳时空变化特征,采集了典型河流、湖泊、冰川等水体样品,通过实验室测试分析获取了总碳、无机碳和有机碳观测数据。结果表明青藏高原典型河流与湖泊水体碳以无机碳为主、有机碳为辅。其中,长江、黄河和澜沧江源区典型河流与湖泊水体总碳平均含量分别为62.46,32.88,17.70 mg/L,长江南源当曲源、正源沱沱河源和北源楚玛尔河源水体总碳含量分别为32.90,36.56,32.90 mg/L;青藏高原封闭性湖泊水体碳含量比河流水体较高,封闭性湖泊水体总碳、总无机碳和总有机碳平均含量分别为403.82,398.35,1.24 mg/L,而河流水体则分别为17.03,14.56,2.46 mg/L,河流水体有机碳含量比封闭性湖泊水体较高。该成果可为我国青藏高原水域碳循环研究提供基础数据,对高海拔区域气候变化研究具有参考价值。     

GRACE反演近年青藏高原及雅鲁藏布江流域陆地水储量变化

利用2005年至2010年6年的GRACE(Gravity Recovery and Climate Experiment)数据反演,研究了青藏高原地区以及雅鲁藏布江流域的季节及年陆地水储量的变化情况.结果显示:在研究区,伴随着显著地季节性波动,年水储量均有明显的下降趋势.同时,流域GRACE数据反演结果和国际上几种模式的水文模拟结果比较表明,GRACE在两个流域上的反演结果与CPC水文模型模拟结果变化趋势较为一致,但水储量年、季变化幅度偏大,而与GLDAS发布的CLM与VIC模型的结果则相差甚远,主要原因归结为青藏高原地区气候条件复杂导致模型的不确定性及误差较大,而大多水文模型缺乏对地下水变化的模拟能力所致.     

Content of highly unsaturated fatty acids in fish from rivers of contrasting temperature

Contents of highly unsaturated long‐chain fatty acids of omega‐3 family (HUFA); eicosapentaenoic acid (EPA; 20:5n‐3); and docosahexaenoic acid (DHA; 22:6n‐3) are the principal indicators of the nutritive quality of fish for humans. Effects of environmental factors, first of all water temperature, on EPA and DHA contents in fish tissue are not currently completely understood. To reveal the putative effect of water temperature, fatty acid composition and contents were studied for 6 fish species, inhabiting the cold waters of the Yenisei River (Siberia, Russia) downstream of a dam (hypolimnetic release from reservoir) and its adjacent warm water tributaries (the Mana River and the Kacha River). It was hypothesized that (a) fish species from the cold river would have higher HUFA contents than fish from the warm rivers and (b) temperature would be negatively correlated with HUFA content in fish species. Using gas chromatography–mass spectrometry, distinct species‐specific fatty acid profiles were observed, whereas contents of the essential fatty acids, EPA and DHA, in fish species from the cold Yenisei River were in general similar to that from warm tributaries. Thus, in contrast to the first hypothesis, phylogenetic factors overweighed the effect of water temperature and food (benthic invertebrate) composition, on fatty acid composition and HUFA content in fish. For the second hypothesis, for the 2 species inhabiting both cold and warm rivers, only one had higher EPA and DHA content at lower temperatures. Consequently, the response of EPA and DHA content in fish tissue to temperature variations may be species‐specific.     

长江攀枝花—宜昌江段水温时空变化规律

受气候变化、梯级水库运行及支流入汇等多重因素影响,长江攀枝花—宜昌江段水温的时空分布发生了显著变化,其必将对河流生态系统产生深远影响。选择干支流控制性水文站1956—2016年近61 a水温资料,采用归因分析和多尺度对比分析,研究了该江段水温的时空变异特性及沿程分布。结果表明:攀枝花—宜昌江段干流升温趋势明显,而支流岷江受气温变冷带影响,1956—1990年间水温持续下降1 ℃,其后逐渐回暖;年内水温极差逐年减小,减小幅度为0.38~1.46 ℃/(10 a),水温年内过程趋于平坦;梯级水库建设使屏山站和宜昌站下游河道春、夏季水温降低而秋、冬季水温升高,其中4月份与12月份的变化幅度较大,这2个站点在4月份和12月份的水温分别较蓄水前改变-2.6 ℃和4 ℃左右;沿程水温格局总体稳定,即干流攀枝花—屏山江段持续升温超2 ℃;低温、量大(流量占比50%以上)的岷江水入汇,使屏山—朱沱江段水温下降0.6 ℃;嘉陵江高温水与乌江低温水由于流量占比不大,对朱沱—宜昌江段水温影响亦不大。研究成果可为上游梯级水库开展生态调度及建立生态补偿机制等提供科学依据。     

热带地区水库水温分层特性研究

为探讨热带地区水库水温分层特征,采用垂向一维水温数学模型对海南省南渡江干流某拟建大型水库开展了水库垂向热分层结构和下泄水温过程研究,并探讨了叠梁门分层取水措施对低温水的改善效果。研究结果表明:①受水库湖泊特性和气候特征影响,海南热带地区水库水温总体也呈现随季节变化的分层结构,在冬季水温趋于同温,夏季水温分层逐渐加强且显著,年内垂向最大温差可达11.8℃,由于海南主汛期为9～10月,汛后水库蓄热能力明显减弱。②水库下泄水温呈现低温水明显、高温水较弱的规律,最大降幅9.7℃,最大升幅仅为1.0℃。③叠梁门分层取水措施的运用,加强了水库垂向分层状态,对低温水的改善效果显著,最大低温水影响降低为2.3℃。     

水库下游河道水温沿程分布的解析解及与其他方法的比较

在考虑沿流向的温度梯度、假设河流水面热交换通量沿程恒定的基础上,根据河道一维水温控制方程推导出解析解,并与国内常用的一种河道水温计算解析解的简化解法作了较详细的对比。结果表明,基于热交换通量沿程恒定的解析解具有较高的精度,能较好地模拟水库下游河道水温复温过程。以安徽白莲崖水库为例,在预测白莲崖水库水温结构的基础上,利用推导的解析解对白莲崖水库下游河道水温沿程分布进行了预测,并分析了水库下游河道水温对周围环境的影响:白莲崖水库下游河道长期处于低温环境,河水不适于浇灌两岸的农作物,对鱼类生长、繁殖也产生一定的不利影响,需将其他温度适宜的水源输至农田进行灌溉,适合鱼类生长、产卵的场所将向下游推移。     

温排水对长江安徽段水温的影响模拟

为研究温排水对长江安徽段水温的影响,建立长江干流安庆至芜湖段三维水动力温度输运模型,根据水文实测数据对模型参数进行率定及验证,分别在纵、横断面上预测分析了不利条件下两种排放工况(减排前、减排后)对周边水域温度的影响范围及程度.结果表明:在两种排放工况下,保护目标水温均未受影响;水体温升分布有显著垂向差异,随着水深增加,...     

Identifying Temperature Thresholds Associated with Fish Community Changes in British Columbia,Canada, to Support Identification of Temperature Sensitive Streams

We collected fish samples and measured physical habitat characteristics, including summer stream temperatures, at 156 sites in 50 tributary streams in two sampling areas (Upper Fraser and Thompson Rivers) in British Columbia, Canada. Additional watershed characteristics were derived from GIS coverages of watershed, hydrological and climatic variables. Maximum weekly average temperature (MWAT), computed as an index of summer thermal regime, ranged from 10 to 23 °C. High values of MWAT were associated with large, warm, low relief watersheds with a high lake influence. Measures of community similarity suggested that the fish community changed most rapidly through a lower transition zone at an MWAT of about 12 °C and an upper transition zone at an MWAT of about 19 °C. These results were confirmed using existing fisheries inventory data combined with predictions of MWAT from a landscape‐scale regression model for the Thompson River watershed. For headwater sites in the Chilcotin River watershed (which drains into the middle Fraser River), the relative dominance of bull trout versus rainbow trout (based on inventory data) decreased with increasing predicted MWAT although the distinction was not as clear as for the Thompson River sites. The fish communities in these watersheds can be characterized in terms of very cold water (bull trout and some cold water species), cold water (salmonids and sculpins) and cool water (minnows and some cold water salmonids). The two transition zones (ca 12 and 19 °C) can be used to identify thresholds where small changes in stream temperature can be expected to lead to large changes in fish communities. Such clear, quantifiable thresholds are critical components of a management strategy designed to identify and protect vulnerable fish communities in streams where poor land use practices, alone or in combination with climatic change, can lead to changes in stream temperatures. Copyright © 2015 John Wiley & Sons, Ltd.     

长江源区浮游植物群落特征与水环境因子关系研究

为研究长江源头区域河流浮游植物群落结构与水环境因子的关系,于2017年5,8,9月份和2018年5,7,9月份在长江源区进行调查分析,并对浮游植物及水环境因子进行了Pearson相关性分析和典范排序分析。结果表明,共发现浮游植物6门79种,以硅藻门和蓝藻门为主。各采样点浮游植物平均密度71.66×10⁴ ind./L。典范分析表明,温度、化学需氧量、高锰酸盐指数、氨氮、总氮、溶解氧是影响长江源区河流浮游植物群落结构的主要因子。研究成果有助于了解长江源头地区浮游植物群落特征,为三江源生态保护提供数据支撑。     

Effect of Fish Age on Predicted and Observed Chronic Toxicity of Lead to Rainbow Trout in Lake Ontario Water

Exposure of rainbow trout (Salmo gairdneri) starting at the egg stage to water-borne lead in Lake Ontario water (hardness of 135 mg CaCO₃/L) resulted in black tails (early symptoms of spinal deformities) at lead concentrations as low as 22 μg/L. No black tails were observed at 11 μg/L. Previous publications demonstrated that the lowest lead concentration causing black tails in trout exposed from the fingerling stage in Lake Ontario water was 120 μg/L, suggesting that fish exposed from the egg stage are 5 times as sensitive as those exposed from the fingerling stage. Compared to previously published data on fish exposed from the egg stage, blood lead of fish exposed from the egg stage was greater for a similar lead exposure. However, the relationship between blood lead and enzyme inhibition (erythrocyte δ-amino levulinic acid dehydratase) was unchanged. Therefore the increased sensitivity of trout exposed from the egg stage was probably due to enhanced lead accumulation rather than to an enhanced response to the lead taken up. The incidence of black tails at this hardness corresponded well to a prediction based on published lead toxicity at extremes of water hardness.