Lakes and Reservoirs: Research and Management
About: Lakes and Reservoirs: Research and Management is an academic journal published by Wiley-Blackwell. The journal publishes majorly in the area(s): Water quality & Eutrophication. It has an ISSN identifier of 1320-5331. Over the lifetime, 761 publications have been published receiving 12505 citations. The journal is also known as: Lakes and reservoirs : science, policy and management for sustainable use & Lakes and reservoirs.
Papers published on a yearly basis
TL;DR: In this article, the authors proposed a management of tropical lakes for the protection of water quality, aquatic life and other uses in the tropics from how it is approached at temperate latitudes.
Abstract: Management of lakes for the protection of water quality, aquatic life and other uses must be approached somewhat differently in the tropics from how it is approached at temperate latitudes. More than half of all tropical lakes are accounted for by natural river lakes or reservoirs. Therefore, degradation of water quality in rivers will have direct negative effects on the majority of lakes in the tropics. Also, regulation of rivers, which is one result of river impoundment, is a potential cause of damage to river lakes. Tropical lakes are more sensitive than temperate lakes to increases in nutrient supply and show higher proportionate changes in water quality and biotic communities in response to eutrophication. Tropical lakes are especially prone to loss of deep-water oxygen, and in order to maintain ecological stasis therefore require more stringent regulation of organic and nutrient loading than temperate lakes. Nutrient containment must be more strongly oriented toward nitrogen, the most probable limiting nutrient in tropical lakes, than has been the case at temperate latitudes. However, phosphorus control is also important. Nitrogen management may be more feasible in the tropics because of high temperature, which is one of the critical conditions for efficient denitrification. Planktonic and benthic communities of the tropics bear a close resemblance, both in composition and diversity, to those of temperate latitudes; there is no parallel to the latitudinal gradient in biodiversity that is characteristic of terrestrial ecosystems. Foci of biodiversity, which require special attention, include the endemic species of ancient lakes and the diverse fish communities of very large rivers. The latter are an especially valuable untapped economic resource, but face severe impairment due to hydrological regulation and pollution of rivers. Effective management programs for tropical lakes will focus on interception of nutrients, protection of aquatic habitats from invasive species, and minimization of hydrological changes in rivers to which lakes are connected. In the absence of protective management, tropical lakes will decline greatly in their utility for water supply, production of commercially useful species, and recreation.
TL;DR: In this article, the authors highlight the social, economic and environmental costs and comment on management responses for salinisation in semi-arid and arid regions of the world.
Abstract: Semi-arid and arid regions (ie drylands with annual mean rainfall between 25 and 500 mm) cover approximately one-third of the world’s land area and are inhabited by almost 400 million people Because they are a resource in short supply, waters in drylands are under increasing human pressures, and many are threatened by rising salinities (salinisation) in particular Rising salinities result from several causes The salinities of many large natural salt lakes in drylands are rising as water is diverted from their inflows for irrigation and other uses The excessive clearance of natural, deep-rooted vegetation from catchments and the discharge of saline agricultural wastewater causes the salinity of many freshwater lakes, wetlands and rivers to rise The salinisation of some fresh waters is caused by rising saline groundwaters And in some regions, increasing climatic aridity may be a cause of salinisation Whatever the cause, salinisation has significant economic, social and environmental impacts They are usually deleterious and often irreparable Decreased biodiversity, changes in the natural character of aquatic ecosystems, and lower productivity are frequent ecological effects In some dryland countries, salinisation is viewed as the single most important threat to water resources However, the extent and importance of salinisation as a global threat has been greatly underestimated Recognition of this is the first step in any attempt to manage it effectively The aims of the present paper, therefore, are three-fold First, it aims to define the problem and indicate its extent; second, it aims to outline the causes and effects of salinisation; third, it aims to highlight the social, economic and environmental costs and comment on management responses An overarching aim is to draw attention to the importance of salinisation as a phenomenon of global significance to waters in drylands
TL;DR: In this paper, the results of long-term investigations into the concentrations of some heavy metals (Fe, Mn, Cu, Zn, Pb, Cr, and Cd) in the bottom sediments of the Dnieper reservoirs and the Dniper-Bug estuary are considered.
Abstract: The results of long-term investigations into the concentrations of some heavy metals (Fe, Mn, Cu, Zn, Pb, Cr, and Cd) in the bottom sediments of the Dnieper reservoirs and the Dnieper–Bug estuary are considered. Maximum quantities of the metals studied are characteristic of southern water bodies located within industrial zones (the Zaporozh’e and Kakhovka reservoirs as well as the Dnieper–Bug estuary). The highest concentrations of the metals studied occurred in the clay silts (Fe, 11 600–32 400; Mn, 1504–3450; Cu, 38.9–85.5; Zn, 89.8–186.5; Cr, 48.6–193.0; and Cd, 1.9–4.4 mg kg-1 dry weight). Accumulation of heavy metals in the bottom sediments is an important factor in the self-purification of aquatic environments. However, this process is reversible and therefore provides a constant threat of secondary water pollution. Secondary water pollution is observed in summer and autumn when water consumption increases. The concentrations of heavy metals increase by a factor of 1.5–3 after the drawdown of the water level. The main reason for the rise in the concentrations of metals is exchange between the bottom sediments and the water column. The rate of heavy metal migration is connected with the forms of occurrence in solid substrates and pore solutions in the bottom sediments, as well as with physico-chemical conditions arising at the sediment/water boundary. Therefore, our investigations concentrated on the study of the fractional distribution of heavy metals among solid substrates and their forms of occurrence in interstitial solutions. This distribution depends, most of all, on the chemical properties of metals as well as the chemical and mineralogical composition of the sediments and the chemical properties of pore solutions. Most of the supply of Mn, Zn, Fe, and Cd is associated with oxides and hydroxides of iron and manganese (Mn, 74–93%; Zn, 43–70%; Fe, 27–59%; and Cd, 28–41%). Most copper and chromium is bound to organic matter and to scarcely soluble minerals. In the interstitial solutions studied, metals (except manganese) are found mainly as complex compounds with dissolved organic matter of a different molecular weight. Nevertheless, the fraction of complexes with a relatively low molecular weight (500–5000 Da) prevailed (40–70%). Dissolved manganese in the pore solutions consists chiefly of free (hydrated) ions Mn2+ (80–95%). The results obtained were used for a comparative evaluation of heavy metal mobility and the exchange ability of their associated compounds in the bottom sediment–water system.
TL;DR: The dominance of C. raciborskii appears to be favoured by a set of environmental and hydrological factors that include long water residence time, high pH, high temperature, high incident irradiation and a thermally stratified water column.
Abstract: Since October 1997, 47 reservoirs and weir pools across tropical and subtropical Queensland have been regularly monitored for the occurrence of planktic cyanoprokaryotes. Cylindrospermopsis raciborskii (Woloszynska) Seenaya & Subba Raju (Nostocales, Cyanoprokaryota) was found in 70% of the storages, with one storage displaying year-round dominance, 50% of the reservoirs seasonally dominated and a seasonal presence in 46% of the weir pools. Maxima for the majority of storages occurred from late summer through to early autumn. The precise timing of onset of seasonal maxima varied considerably between storages and regions. Temperature and stratification patterns influenced seasonal recruitment with C. raciborskii reaching seasonal maxima in southern storages generally later than the northern storages. Overall peak seasonal abundance occurred in deep strongly stratified storages. The majority of storages experiencing concentrations > 15 000 cells mL ‐1 tested positive to the presence of the alkaloid cytotoxin, cylindrospermopsin. Median cylindrospermopsin concentration across the 14 reservoirs in which toxin was recorded was 3.4 m gL ‐1 . The highest toxin concentrations were generally associated with storages in which C. raciborskii had been established for a considerable period of time, or occurred after the peak summer population maxima. Toxin concentrations of 1 m gL ‐1 were generally associated with cell concentrations of approximately 20 000 cells mL ‐1 , hence this cell concentration threshold was adopted as a health trigger level at which to begin monitoring for toxicity. The morphology of this species was highly variable and included straight, coiled and sigmoid-shaped trichomes. Populations were routinely recorded as mixtures of all three morphotypes or proceeded as transitions from one morphotype to another throughout the year. The dominance of C. raciborskii appears to be favoured by a set of environmental and hydrological factors that include long water residence time, high pH, high temperature, high incident irradiation and a thermally stratified water column. The lack of visual monitoring cues, such as scum formation, variation in colour of the water body, rapid germination of large numbers of cells, highly variable morphology, relative toxicity and persistence of this species year round in many areas, continues to make this species a primary focus of water managers.
TL;DR: The Aral Sea, a once vast brackish terminal lake in the heart of Central Asia, has been rapidly drying since the 1960s, and it had separated into four separate waterbodies by September 2009 as mentioned in this paper.
Abstract: The Aral Sea, a once vast brackish terminal lake in the heart of Central Asia, has been rapidly drying since the 1960s. It had separated into four separate waterbodies by September 2009. The maximum water level decline was more than 26 m, whereas the lake surface area decreased 88% and the water volume 92%. The lake salinity increased by more than 20-fold. Prior to the modern recession, the Aral Sea experienced a number of water level declines and subsequent recoveries over the last 10 millennia. The main causative factor until the 1960s was the periodic westward diversion of the Amu Dar’ya, the main influent river, towards the Caspian Sea by both natural and human forces. The post-1960 recession, however, was overwhelmingly the result of unsustainable irrigation development. The lake’s modern recession has caused a broad range of severe negative ecological, economic and human welfare problems. To restore the Aral Sea to its 1960s’ size and ecological condition would be very difficult, if not impossible, in the foreseeable future. The plight of the Aral Sea, however, is far from hopeless. Partial restoration of portions of the lake is still feasible. A project to raise the Small (northern) Sea was completed in Fall 2005, raising its water level by 2 m, and lowering its salinity to a level not much higher than the early 1960 levels. Its ecological recovery has been dramatic, and a new project to improve further the Small Aral was recently announced. Improving the Large (southern) lake would be much more difficult and expensive. A project to save the deep Western Basin partially is technically feasible, however, and should be given careful evaluation. It is important to repair and preserve what is left of the deltas of the two tributary rivers, Syr Dar’ya and Amu Dar’ya, as these two rivers are of great ecological and economic value, and act as biological refugia for endemic species of the Aral Sea.