Organic matter governs N and P balance in Danube Delta lakes

The transformation of dissolved inorganic nitrogen (DIN) and soluble reactive phosphorous (SRP), and the release of dissolved organic and particulate N and P, were analyzed in two lake complexes (Uzlina–Isac and Puiu–Rosu–Rosulet) of the Danube Delta wetland during flood conditions in May and at low water level in September 2006. The Uzlina–Isac complex was hydrologically tightly-connected with the Danube River and was flushed with river-borne nutrients and organic matter. These lakes acted as effective transformers for nutrients and produced large amounts of fresh biomass, that promoted the excretion of dissolved organic N and P during active growth. Biomass breakdown created particulate matter (<0.45 μm), which was widely liberated during low flow in the fall. The Puiu–Rosu–Rosulet complex was characterized by a more distant position to the Danube and proximity to the Black Sea, and received dominantly transformed organic compounds from the flow-through water and vast vegetation cover. Due to reduced nutrient input, the internal production of organic biomass also was reduced in these more remote lakes. Total N and P export from the lake nearest to the shelf was governed by dominantly dissolved organic and particulate compounds (mean 58 and 82%, respectively). Overall, this survey found that these highly productive wetlands efficiently transform nutrients into a large pool of dissolved organic and particulate N and P. Hence, wetland lakes may behave widely as net sources of organic N and P to downstream waters and coastal marine systems.     

Production-destruction processes in water and the accumulation of matter on the beds of lakes and reservoirs

Direct stochastic relations between organic matter destruction in the water column and the rate of substance sedimentation onto reservoir bed, as well as the correlation between plankton primary production and the rate of substance sedimentation onto the beds of lakes and reservoirs are discussed. The vital activity of bacterial biomass colonizing mineral particles as the latter settle onto the bottom is asserted to be the mechanism forming the aforesaid relations.     

Iron distribution in surface waters in the Middle and Lower Amur basin

New data on iron concentration and distribution in solution and suspension in the water of the Amur and its major tributaries (the rivers of Bureya, Sungary, etc.) collected in 2006?C2009 are given. The distribution of iron over river gauges and along the Amur was found to be uneven. The correlation between iron and humic acids was for the first time assessed in rivers and lakes of the Middle and Lower Amur basin.     

Allometric relations between fluvial impulse and morphometric parameters of floodplain lakes

The general role of river water input in shaping the basic morphometric parameters of floodplain lakes has been previously investigated. However, the process has not been quantitatively described in detail. This study is the first attempt in the literature to determine the allometric relation between fluvial impulse, expressed as Fluvial Connectivity Quotient, and morphometric parameters of six floodplain lakes of Bug River valley in the period 1952–2014. This relationship is given by Y = aX^b, from which the value of b exponent was analysed to determine the strength of the allometric relation. Extreme values of allometric compounds during the time period under study ranged from 5.99 to ?4.91. Volume was the morphometric parameter showing the highest variability in all the lakes. General similarity in allometric relations was observed in the lakes under study. During analysis, no long‐term trends were observed in the relationship between the Fluvial Connectivity Quotient and morphometric parameters. The results obtained show that fluvial impulse was the factor determining the variability of morphometric parameters of the lakes. Direct catchments topography of lake has periodically (during limnophase periods) played a significant role in shaping the morphometry of floodplain lakes. The most stable allometric relations occurred in a confluent lake, with a low limnological effective rise value and consequently, relatively long potamophase periods.Copyright © 2015 John Wiley & Sons, Ltd.     

Organic matter of the Kiziltashskie Limans

Data on biochemical ecosystem monitoring of Kiziltashskie Limans are given. The limans are the only natural water bodies in the Russian Black Sea where pascual breeding of very valuable commercial fish is implemented. The presented concentrations of dissolved and particulate organic matter are 2–5 times greater than the values typical of the coastal zone of the Black Sea (from 7.9 to 27.7 mg/L and from 0.3 to 1.5 mg/L, respectively). The main biochemical component of the dissolved organic matter is carbohydrates, and that of particulate matter is protein. The share of particulate organic matter in the Kiziltashskie Limans never exceeds 7%. The elemental (C, N, P) and biochemical composition of organic matter is studied (carbohydrates, proteins, lipids). The rates of enzymatic reactions vary from season to season. Thus, processes of hydrolytic splitting of phosphor-organic compounds during primary production are very intensive in the spring, while processes of organic matter oxidation, catalyzed by enzymes of electron-transport system, are intensive in the summer.     

江汉湖群基准环境与现代环境中的摇蚊属种组合变化

了解湖泊生态系统基准环境和历史演变规律是进行湖泊生态环境保护和管理的关键.本文研究江汉湖群32个浅水湖泊现代环境和基准环境下的摇蚊组合特征,分析摇蚊组合变化的趋势和影响因素,并探讨了江汉湖群生态和营养参考值.研究发现Paratanytarsus penicillatus-type、Microchironomus tener-type、Cricotopus sylvestris-type、Polypedilum nubifertype、Dicrotendipes nervosus-type、Procladius等为基准环境下的摇蚊优势种.现代环境中Chironomus plumosus-type、Microchironomus tabarui-type、Procladius、Tanypus、Propsilocerus akamusi-type等富营养种明显增多.摇蚊组合CONISS聚类分析结果表明,32个湖泊主要分为3类,其中21个湖泊(第Ⅰ、Ⅱ类)的摇蚊属种与基准环境相比发生了显著变化,主要原因是流域营养盐输入和水生植被的破坏.本研究介绍了摇蚊古生态研究在重建湖泊基准环境方面的应用,并为湖泊管理和生态修复提供参考数据.     

Long-term variability of nitrate and nitrite nitrogen runoff in the Amur River near Khabarovsk

The long-term dynamics of the runoff of mineral oxidized forms of nitrogen in the Amur River near Khabarovsk City is discussed. An increase in nitrate nitrogen runoff by a factor of 2.1 is recorded as compared to the period of 1981–2000. It is shown that the Sungari River is now responsible for the formation of the anthropogenic component of the runoff of mineral nitrogen forms.     

Organic matter in ancient meteorites

Fragments of ancient meteorites are cosmic time capsules, holding records of the first chemical steps towards life. Mark A Sephton explains what they have revealed so far and discusses what secrets they may yet still hold.     

Effect of a Flood in the Amur River on Organic Matter Dynamics in Groundwater

The space and time dynamics of organic matter concentration in groundwater in the Tungusskoe deposit during the historical 2013 flood in the Amur River is discussed. For comparison analysis, several methods for determining the quantitative characteristics of organic matter (spectrophotometry, gas-chromatographic mass spectrometry, and high-performance liquid chromatography) were applied to different layers of an aquifer at different distances from the shore line. The genesis of many organic substances is due to the inflow of river filtrate and surface water from the inundated floodplain. In the post-flood 2014, groundwater showed a decrease in the total amount of organic components and the presence of low-molecular hydrocarbons, diphenylamine, cosanes, phenanthrene, naphthalene, and derivatives of stearic and palmitic acids. Toxic methyl benzene was identified in most wells.     

Impact of environmental factors on bacterial communities in floodplain lakes differed by hydrological connectivity

We analysed total bacterial number and mean volume of cells at three sites in each of ten floodplain lakes in the Middle Basin of the Biebrza River, North-Eastern Poland to test bacterioplankton communities change according to the distance to the river. The composition of the bacterial communities was determined by fluorescent in situ hybridization method. Total number of bacteria in the lakes ranged from 4.0 to 7.48 cells × 10⁶ mL⁻¹ with dominance by Actinobacteria, the contribution of which was positively correlated with water level. Old river channels (side-arms) featured Alpha- and Gammaproteobacteria. The community of Betaproteobacteria was limited by concentration of dissolved organic carbon. Archaea, in spite of a minor role (<3.65% of DAPI-4′,6-diamidino-2-phenylindole) in the communities, showed a positive relation to floodplain lake isolation. Multivariate analysis demonstrated that bacterioplankton in riverine lakes was similar to that in rivers, while lakes with limited water exchange showed a similarity to fertile lakes. Water level and nutrients were among the factors determining bacterial community structure.     

Trace elements in surface water in Amur River basin

A wide range of trace elements contained in solution and suspension in surface waters in Amur River basin, which are subject to different anthropogenic load, has been considered. They have been found to vary widely because of their natural conditions, the impact of anthropogenic factors near cities (Khabarovsk, Komsomol’sk-on-Amur), and transboundary transport from the territory of China. Dissolved Mo, Br, and I are proposed as tracers of such transport.     

Variations of Amur water chemistry during the historical 2013 flood

Water chemistry in the Amur R. at Khabarovsk was studied during the historical 2013 flood. The concentrations of dissolved substances were shown to vary significantly over both time and space, because of the difference between the discharge and chemistry in the main flood-forming tributaries. The ion runoff, nutrient runoff, and microelement runoff were estimated for the flood peak and all over flood period.     

Large scale water movements in lakes

By large scale circulation in lakes one means motions whose characteristic length scales extend over most parts or all of the water masses in a lake or the ocean. We present the governing equations and motivate, by means of a scale analysis, the various simplified versions of model equations that are in use in computational lake dynamics. This scale analysis not only permits rational deduction of the reduced equations, it equally provides a means of estimating their limitations. These are discussed as are the difficulties and the peculiarities inherent in the proposed equation sets.Special features of external and internal wave motions are studied. For barotropic oscillations of a lake system (Lake of Lugano) it is shown that substantial water masses are exchanged between the individual basins at the resonating periods. Baroclinic seiches of a three layer model in which each layer is effective within its own domain show (for the North basin of the Lake of Lugano) that mode structures may differ from layer to layer pointing at important modifications of classical interpretations of higher baroclinic wave dynamics. And in large lakes in the equatorial belt the-effect forces modifications of the classical understanding of seiche behavior. Long periodic oscillating features may be attributed to topographic Rossby waves or higher baroclinic internal gravity waves; the observational identification is, however, difficult because lack of spatial resolution of the data makes this identification non-unique. We, finally present results of a full nonlinear numerical baroclinic circulation model and demonstrate that it is able to reproduce the gross features of the immediate response to strong storms during a few days.This paper is an extended version of a lecture with the same title, held by K. Hutter on June 14, 1989, at the Workshop Spatial and temporal scales of water bodies of the Sonderforschungsbereich Stoffhaushalt des Bodens, Universität Konstanz. The character of the paper is that of areview, however, it contains material, theoretical, computational and observational, that has never been presented before to make it sufficiently unique. Some of the new material has been collected and gathered by E. Bäuerle, G. Salvadè, C. Spinedi and F. Zamboni, who should be credited for it, even though none of these people contributed to the layout and drafting of the text, for which K. Hutter is responsible alone.We thank Professor Max Tilzer of the University Konstanz for inviting K. Hutter to the workshop and giving him the opportunity to present the material as of that time.As far as referencing current literature is concerned we are neither exhaustive nor complete and only refer to literature which is directly related to the material presented. For a list with more than 300 relevant references, the reader may consult the article Hydrodynamic Modeling of Lakes by K. Hutter in the Encyclopedia of Fluid Mechanics, Gulf Publ. Company, Houston Texas (1987). I would like to express my sincere thanks to Mrs. Danner for her diligent work in typing the text.     

云南高原湖泊有色可溶性有机物和颗粒物光谱吸收特性

云南高原湖泊是我国湖泊分布最密集的五大湖群之一,不但湖泊数量众多而且类型多样.由于湖泊所处位置海拔较高,容易受只益增强UV-B辐射影响.通过对云南高原34个湖泊有色可溶性有机物和颗粒物吸收测定,分析其光谱吸收特性及对总吸收的贡献,有利于深刻理解紫外辐射在高原湖泊内衰减.不同湖泊间CDOM吸收差异明显,其大小与水体营养盐状况相关,CDOM吸收系数与水体总氮存在显著正相关.增加背景项的指数函数模型能最好模拟CDOM光谱吸收.除在浮游植物浓度非常高的杞麓湖、听湖、星云湖,颗粒物吸收系数在675nm附近存在一个吸收蜂外,其它湖泊总颗粒物光谱吸收大致随波长的增加吸收系数逐渐降低,呈现非色素颗粒物光谱吸收特征,整体上颗粒物吸收以非色素颗粒物为主.CDOM对总吸收的贡献主要集中在600nm以下波长,尤其是400nm以下的紫外波段,其在紫外波段(350-400nm)的贡献明显要大于光合有效辐射波段(400-700nm)(ANOVA,P<0.001).特别对于透明度SD≥1.0的清澈型湖泊,CDOM吸收对紫外辐射衰减的贡献更大,其吸收很大程度上决定了紫外辐射的影响深度.     

Basic physicochemical characteristics of the state of Upper Amur surface water

The present-day ecological state of the Upper Amur is assessed. Specific features of water quality formation are demonstrated. Local sources of aquatic environment pollution are identified. The distributions of metals in dissolved and suspended forms in the river reach are examined.     

Intensity of in‐lake processes in floodplain lakes within the Bug River zone of fluvial activity

The paper presents a new approach to calculating the erosion and deposition values of floodplain lake basins, the erosion–deposition index (EDI). The EDI is a sum of the basin geometry indices (BGIs), which can be calculated for a separate cross section of the lake. The distribution of processes within the basin was investigated in two selected floodplain lakes with the use of BGIs. Field research was carried out in the Bug River valley from 1 November 2006 to 31 October 2011. The highest erosion was observed in the lakes located close to the parent river. Deposition processes were observed in lakes with high inflow of groundwater. The results showed that EDI values of 48 out of the 71 floodplain lakes ranged from ?0.2 to 0.2. Spatial distribution of erosion and deposition processes within the lake basins resulted from a velocity of water inflowing or flowing through the basin. This was observed especially in contrafluent–confluent lake. Inflow of rivers water via upstream crevasse occurred later than via downstream one, but energy of flowing water was higher, which favoured erosion of this part of the lake basin. Copyright © 2013 John Wiley & Sons, Ltd.     

Dissolved and suspended organic mater in the Amur and Songhua River water

Results of studying the concentration of total, dissolved, and suspended organic matter in the water of the Amur and its main tributaries (the rivers of Bureya, Songhua, etc.) in 2005–2006 are presented. A high concentration of organic matter of anthropogenic origin was recorded in the water of the Songhua River, which has a significant effect on the Amur water quality. The export of organic matter with the Amur River water into the Amur Liman was accessed.     

On the secular change in water level of lakes in Finland

Summary In some larger lakes in Finland continuous lowering of the water level can be established. This is presumed to be chiefly the consequence of secular changes in climate.