Some effects of eutrophication and the removal of aquatic plants by grass carp (Ctenopharyngodon idella) on rainbow trout (Salmo gairdnerii) in Lake Parkinson,New Zealand

Temporary removal of aquatic plants in Lake Parkinson, a small, eutrophic dune lake, resulted in a number of changes to the population of stocked rainbow trout (Salmo gairdnerii). During each summer the lake stratified and low oxygen levels limited the distribution of trout to shallow (0–4 m) surface waters. In the first summer following weed removal the numbers of black shags (Phallacrocorax carbo) counted at the lake increased, and their predation resulted in a decline in trout density. However, the growth rate and condition of the trout population then exceeded that of trout present before weed removal. During the second summer after weed removal a cladoceran bloom was followed by low phytoplankton levels and high ammonia concentrations. A prolonged calm compounded this situation with the result that oxygen levels in bottom and surface waters dropped below 2 ppm. These low oxygen levels eliminated the trout population, but other fish species present survived. Elimination of aquatic plants affected the population dynamics of other fish species in the lake with potential implications for the trout. The experiment demonstrated the importance of weed beds in maintaining a stable fish community in lakes such as Lake Parkinson.     

云南程海近500年来湖泊初始生产力的演化

程海为富营养化封闭湖泊，通过对程海CH01乳沉积物色素分析，定性恢复了近500a来程海湖泊初始生产力演化过程，结果表明，近500a来程海湖泊初始生产力总体上呈现由低到高的上升趋势，其中1700AD前后，1790AD前后是湖泊初始生产力出现变化的界限，另外，色素含量变化揭示研究时期内存在1750AD前后，1930AD前后二次明显暖波动。     

青海湖及其水系近30年来的化学变化

根据１９８５－１９８７年来１９８９－１９９１年对青海湖及其水系的考查资料，研究其化学变化。结果表明，近３０年来，青海湖及其入湖河流水系在萎缩过程中，水系总矿化度增加，逐渐咸化。除尕海水的Ｍｇ＾２＋；耳海水的Ｋ＾＋，ＳＯ＾２－４，ＣＯ３＾２－；人湖河流水的ＳＯ４＾２－离子浓度减小外，青海湖、尕海及耳海本中Ｎａ＾＋，Ｃｌ＾－，ＳＯ４＾２－离子增加速率较大，Ｃａ＾２＋，Ｍｇ＾２＋等离子增加速率较小。尕海     

Limnology of Lake Waikaremoana with special reference to littoral and pelagic primary producers

Lake Waikaremoana, the North Island's deepest lake (248 m), lies in a natural forested catchment, but the lake itself has been modified for hydro‐electric power generation and by the introduction of trout, smelt, and adventive aquatic plants. The lake is a warm monomictic water body of low conductivity (82 μS cm^‐1) and a high seasonal water column stability. The waters are oligotrophic, with epilimnetic dissolved reactive phosphorus concentrations typically < 1 mg m^‐3. The concentration of NO₃‐N is seasonally variable but generally high in winter and spring with maximum epilimnetic values approaching 70 mg m ³. This contrasts with other central North Island lakes. Horizontal variability in surface chlorophyll a is low as are the absolute values (< 1–2 mg m^‐3). A notable feature is the formation of a deep chlorophyll maximum within the metalim‐nion comprised largely of Sphaewcystis schweteri as opposed to diatoms and flagellates which normally dominate the epilimnion. Vascular macro‐phytes (maximum biomass 659 g m² dry weight) extended to 9 m and characeans (maximum biomass 447 g m²dry weight) to 16 m. Total phyto‐plankton primary production was calculated as 4524 tCy^‐1 and macrophyte production as 578 t C y^‐1. The proportion of macrophyte to phy‐toplankton production (0.14) is higher than in the other deep lakes of the central North Island.     

台湾地区湖库水酸化之研究

本文旨在探讨酸雨对台湾地区湖泊、水库等自然水域酸化的影响程度。主要内容为建立水域酸化程度之资料，以及不ＰＨ值湖水中，铝离子释放的情形。     

Response of the mesozooplankton community of the St Lucia estuary,South Africa,to a mouth-opening event during an extended drought

Mesozooplankton samples were collected between March 2005 and November 2008 in St Lucia, the largest estuarine lake system in South Africa. St Lucia experienced an extended period of drought before and during the present study. This drought led to natural closing of the estuary mouth as a result of flood-tide marine sediment deposition in 2002. In March 2007 the mouth was washed open by exceptionally high tidal and wave conditions. This resulted in an influx of a large volume of seawater. The mouth closed again in August 2007. Before opening of the mouth salinities in the Estuary were below 10 and large parts of North Lake dried up while South Lake retained a relatively stable waterbody with salinities between 10 and 30. When the mouth opened seawater flooded the system and salinities changed to about 35. After the mouth had closed again in August 2007 salinities increased in the lakes and decreased in the Estuary. The mesozooplankton community was dominated by copepods during all sampling sessions, especially by the estuarine calanoids Pseudodiaptomus stuhlmanni and Acartia natalensis. Mean mesozooplankton densities were significantly higher in South Lake before the mouth opened in March 2007. While zooplankton density decreased when the mouth opened species richness increased with the influx of coastal marine species, especially in the Estuary. Overall zooplankton densities declined progressively as salinity increased to hypersaline levels after mouth closure. Multivariate analyses supported significant differences between the lakes and the Estuary in terms of mesozooplankton community composition. Taxa mostly responsible for the similarities within and dissimilarity between sections of the system were the copepods P. stuhlmanni and A. natalensis with the meroplankton, crab zoeae and mollusc larvae, also contributing significantly after the mouth-opening event.     

The comparative limnology of some New Zealand lakes

The morphometry, environmental conditions, and some physical and chemical data are given for twenty‐four New Zealand lakes: seven are in the southern part of the South Island, the others, excluding Lakes Waikaremoana and Waikareiti, are in the “thermal region” of the central North Island. These lakes form two separate groups and include the largest and deepest lakes in both islands.

The lakes in which stratification was established were found to belong to the class known as warm monomictic Two lakes, Rotorua and Rotoehu, were found to be homothermous throughout the year. Open water surface temperatures did not exceed 23°c in the North Island lakes or 19°c in the South Island, and minimum temperatures recorded were 7°c in the northern lakes and 5°c in the southern. In deep lakes the range of temperature was much less: Wakutipu had a range of 16–8.85°c.

The disappearance level of a Secchi disc varied from 18 m (Lake Taupo) to 0.8 m (Lake Rotongaio). The transparency of the water in the glacial and volcanic lakes was comparable to that of similar lakes in other parts of the world.

It was found that total ions, measured by the ion‐exchange resins reached high concentrations in lakes fed by thermal waters: Rotomahana 14.32m.e./l. By contrast Tikitapu, a seepage lake, had the low concentration of. 0.28m.e./l, and Wakatipu, a glacial fed lake, a concentration of O.58m.e./1. The pH range was 8.1–5.8, the lowest value being in Tikitapu, a volcanic lake. Slightly lower pH values were recorded in the bottom waters of lakes when stratified. Lakes were usually supersaturated with oxygen at the surface, and only a few small lakes showed a hypolimnial deficiency. Silica and phosphate were found in high concentrations in some thermal lakes but nitrogen in the forms measured, was found to be low.     

太湖现代沉积物中磷的沉积通量及空间差异性

在水文状况、水质状况、生态类型均显著不同的三个太湖典型湖区, 利用^210Pb定年测定了近百年来沉积物及磷的沉积通量.结果发现, 三个湖区磷的沉积通量及其变化规律相差很大.发生蓝藻水华暴发的梅梁湾近百年来沉积物和磷的沉积通量都比较小, 只是在近十几年来才有明显增加的趋势; 太湖上游的夹浦沉积物沉积速率近百年来持续增加, 只有表层有所下降, 但表层12cm沉积物中磷的沉积通量却显著下降; 处于太湖下游草型化的胥口湾湖区, 在20世纪60年代以前沉积物沉积通量呈增加趋势, 之后呈下降趋势, 磷的沉积通量则呈振荡下降趋势.研究表明, 太湖沉积物中磷的累积通量具有明显的空间异质性.     

西昆仑山区湖泊初探

本文论述了西昆仑山区湖泊的分布、成因、水化学特征以及其演化历史与高原隆升、古气候变化、高山冰川进退之间的关系。研究结果表明,该区湖泊主要靠暖季高山带的冰雪融水补给,故矿化度的变化与其距补给源的远近密切相关;它们在第四纪期间的演化是高原构造隆升和全球气候变化二者作用的结果;根据现有资料,该区湖泊的演化历史可大致分为3个阶段,即距今4.6万年以前的大湖期,晚更新世晚期的湖面波动期和全新世的湖泊退缩期。     

生物标志化合物对东、西太湖不同湖泊类型的判识

从生物标志化合物的角度,对东、西太湖沉积物中饱和烃组分进行了分析,通过对其正构烷烃碳数分布形式,主峰碳位置、Ｌ／Ｈ等指标对比,对照西太湖中的主要水生植物蓝藻和东太湖中的主要水生植物的饱和烃的组成特征,同时结合常规指标Ｃ／Ｎ的分析结果,对东、西太湖湖泊类型进行判识－西太湖为藻型湖泊,东太湖为草型湖泊。     

山东盐田及新疆盐湖卤虫(Artemia parthenogenetica)生物学测定值的比较

从山东的盐场和新疆的盐湖采集了卤虫卵,进行了干燥、吸水和去壳的卵径、壳厚、无节幼体体长、染色体数目的生物学测定。按照文献[12]的分类,上述研究的卤虫,均属于第二类的孤雌生殖品系。盐湖的卤虫卵吸水和去壳后比盐场的卤虫卵大。而达板城东盐湖的无节幼体是最短的。各盐场的卤虫有2倍体、4倍体及5倍体,艾比湖的卤虫有2倍体和4倍体,达板城东盐湖只有4倍体。     

Sediments of lakes Rotoroa and Rotoiti,South Island,New Zealand

The chemistry and mineralogy of the sediments of Lakes Rotoroa and Rotoiti, South Island, New Zealand (41° 51 S, 172° 38 E and 41° 50 S, 172° 50 E respectively) , were studied. In general, the cation exchange properties, element concentrations, and mineral compositions of the sediments show little variation between samples from each lake. However, some nutrient concentrations, notably exchangeable calcium, magnesium, and potassium, and total nitrogen and sulphur, are higher in sediments from weed beds than in sediments underlying deeper water; iron and manganese concentrations tend to show the opposite trend. Concentrations of exchangeable calcium and total nitrogen, sulphur, manganese, and iron generally decrease down the sediment profiles from the sediment/water interface. Differences between lakes, notably higher concentrations of illite and of the elements potassium, aluminium, titanium, and zirconium, and lower concentrations of calcium in the sediments of Lake Rotoiti than in those from Lake Rotoroa, are probably due mainly to the different geological settings rather than to differences in the diagenetic processes operating within the lakes. Mineralogical analyses indicate that the lake sediments are derived mainly from the valleys of the major inflow rivers rather than from the slopes at the sides of each lake.     

呼伦湖的近期扩张及其与全球气候变化的关系

通过近２０多年湖泊水量平衡分析发现，湖泊水位变化主要由湖盆内径流补给量的丰枯决定。进一步分析揭示，呼伦湖地区乃至整个东北地区，本世纪以来随气温升高，随水有增加的趋势。降水增加导致入湖径流量，湖水位上升，呼伦湖本世纪以来的扩张与内蒙古东部地区其他内陆湖泊的变化一致，但这在我国乃至整个亚洲内陆干旱或半干旱区是独一无二的，为此成为这一地区气候变化的指示器。     

青海湖沉积物有机碳及其同位素的气候环境信息

通过对青海湖沉积物有机碳及其同位素的分析，结合碳酸盐含量的变化特征，探讨了青海湖沉积物有机碳及其同位素组成的环境意义，并且据此分析了青海湖地区近700a来的气候环境演变。青海湖沉积物的有机碳含量及其同位素较好地记录了温度的变化，在有机碳含量高，有机碳同位素低时，气温较高，反之则相反，小冰期的3次冷期以及20世纪以来的升温在该岩心中得以清晰地反映。     

高原湖泊溶解有机质的三维荧光光谱特性初步研究

提要近年来,荧光光谱技术被广泛应用于研究天然水体中溶解有机质(Dissolved Organic Matter,DOM)的物理化学特性。为了理解高原湖泊中DOM的组成、荧光光谱特性及其在湖泊水体中的垂直分布情况,作者利用荧光发射光谱、三维荧光光谱研究云贵高原湖泊红枫湖和百花湖中的DOM。结果显示,高原湖泊DOM主要表现为类富里酸荧光,包括可见区和紫外区两种类型的荧光峰,各种天然水体中都有报道的类蛋白荧光在红枫湖DOM中并不明显,而在百花湖DOM中则有较强的类蛋白荧光。溶解有机质所含三种类型荧光峰(PeakA:紫外区类富里酸荧光峰;PeakB:可见区类富里酸荧光峰;PeakC:类蛋白荧光峰)的荧光强度与溶解有机碳之间没有明显的线性相关关系,可能与高原湖泊水体pH值、DOM在湖泊不同深度由于受到光降解、微生物降解等作用存在差异等因素有关。与有机质结构和成熟度有关的荧光峰比值r(A,C)在1.40—2.09范围内,红枫湖南湖、百花湖DOM样品的r(A,C)值随着水体深度有下降的趋势,而红枫湖北湖DOM的r(A,C)值则随着水体深度有较大起伏,揭示了高原湖泊水体中DOM的结构以及分布情况存在差异。另外,r(A,C)值与pH之间具有良好的正相关关系,其相关系数红枫湖南湖DOM为0.95,百花湖两个采样点DOM分别为0.67、0.75,而红枫湖北湖DOM则显示出一定的负相关性(R2=0.45)。     

湖泊遥感研究进展

湖泊萎缩、湖泊污染以及湖泊富营养化是人类面临的主要湖泊环境问题。遥感技术的诞生给大范围的、全面深入的湖泊环境变化研究带来了巨大的福音，它克服了人类对湖泊有限的考察和小范围定点观测实验研究的局限性。本文简要综述了国内外遥感技术在湖泊动态变化、湖区洪涝灾害、湖泊物理参数、湖泊生物生态、湖泊水文水质、湖泊冰情等方面的研究进展情况，并论述了遥感技术在湖泊环境变化研究中的未来发展趋势。     

Community succession of zooplankton in marine derived saline lakes in antarctic continental margin

Ecological research has been made for quite a long period in some marine-derived saline lakes in the Vest-fold Hills, Antarctica. The results show distinct succession of zooplankton community in those lakes. The change in community structure of zooplankton is related directly to environmental evolution in nature and the variation of lake conditions, such as physical and chemical factors as well. In the Burton Lake, there is a rather stable annual fluctuation in both temperature and salinity, and the community has probably been in the stage of climax succession. The Fletcher Lake is still undergoing a process by unregular tide flood from nearby bay, so that zooplankton community has been changing due to variance in temperature and salinity.     

Limnology of Lake Ngahewa,North Island,New Zealand

The water chemistry, flora, and fauna of Lake Ngahewa are described. Its waters are coloured by humic material from a flax swamp and the mean carbon: nitrogen ratio of the sediments lies in the range for dystrophic lakes. Thermal stratification is very weak or absent during summer, although deoxygenation occurs at depths below 3 m in late summer. The lake is highly productive and has a diverse phytoplankton and zooplankton population, which is different in species composition from other nearby eutrophic lakes; some algal species common in nearby eutrophic lakes are absent, and there is a high ratio of rotifers to cladocerans and copepods.

The high levels of dissolved phosphorus (42.2 mg.m^‐3) and nitrogen (up to 36.1 mg.m^‐3 NO3‐N) in the lake waters, and the differences in the flora and fauna compared with neighbouring lakes give only weak support to its tenuous classification as a dystrophic lake on the basis of water colour and sediment carbon values. The concept of dystrophy is discussed.     

Comparison on ecological and physiological characteristics of Drepanopus bispinosus (Copepoda: Calanoida) between two populations in Burton Lake and Fletcher Lake, two Antarctic lagoons

Calanoida copepod, Drepanopus bispinosus occurred in both saline lakes, Burton ( S=40) and Fletcher ( S = 56) in Vestfold Hills, Antarctica. Evident differences between two populations in biology and physiology were observed in September and December, 1984. The population in the Burton lake was denser with stronger body and more tolerant to temperature and salinity than that in the Fletcher Lake, reflecting their possible differences of genetic or nongenetic adaptation. The population in the Burton lake has been adaptated to the lake environment, and the population in the Flethcer Lake is in the acclimatization course in the lake habitat.     

洪泽湖风生流数值模拟

湖流是湖泊中污染物质扩散，悬浮物沉降及输移等的主要水动力学要素，造成湖水运动的成因机制很复杂，其中风生流是重要形式，本文通过构造一个二维闭边界数值模拟，对不同风情下的洪泽湖湖流流态进行模拟研究，探讨其入流较小，沿岩各闸关闭的枯季情况下的风生流特征。