A study of the problems associated with Dalangdian reservoir, China

There are over 2,300 lakes over 1 km2 in China (total area 80 000 km2). In addition there are approximately 87 000 reservoirs with a storage capacity of 413 billion m3. These form the main supply of drinking water as well as water for industrial and agricultural production and aquaculture. Because of a lack of understanding of the frailty of lake ecosystems and poor environmental awareness, human activities have greatly affected freshwater systems. This article focuses on the problems of one water supply reservoir, Dalangdian Reservoir, and considers options for improving its management. Dalangdian Reservoir is described and occurrence of algal genera given. The authors conclude with remarks on the future of the Dalangdian Reservoir

Agonizing over limnology

Some of you may have followed the exchange of views on the future oflimnology which has appeared in Limnology and Oceanography (Jumars1990; Wetzel 1991a, b; Kalff 1991). I would not wish to prolong thedebate, but I do feel that there is a peculiarly British perspective to theproblem which has not been considered to date. Amongst the problemsidentified by the authors listed above are "the failure of political leadersto appreciate the importance of freshwater resources and the failure ofteachers of limnology to produce scientists who can deal effectively withthe physics, chemistry, and biology of the resources". One solutionproposed is to provide better and more integrated teaching in schools oflimnology. Whether limnology (or environmental sciences, or evenecology) is a suitable subject for a first degree without some previousspecialisation is a matter for debate. Some would argue that it would bemore appropriate for an advanced degree course, and that limnologicalproblems are better tackled by multidisciplinary institutions than bygeneralists

Some observations on the absence of bacteria from acid waters in northwest England

The effect of acidity is most marked in nutrient-poor waters and this isreflected in its impact on the biota at all levels. The effect may be direct,for example on the physiology of fish and invertebrates, may involvemobilization of the toxic element aluminium, may reduce primaryproduction by altering the community structure of the algae, or may beindirect through its impact on the processing of organic carbon. We donot intend to provide a major review of the acid rain literature, as thisinformation is readily available elsewhere (Norton et al. 1989) as arereports of detailed case studies (Kerekes 1989). In this brief report weshall concentrate on the effect of low pH on the initial stages ofdecomposition and the conditioning of incoming particulate carbon ordetritus by microbes, particularly certain genera of filamentous bacteria

A study of the problems associated with Dalangdian reservoir, China

There are over 2,300 lakes over 1 km2in China (total area 80 000 km2,accounting for about 0.8% of the total area of the country and with a totalfreshwater storage capacity of 225 billion m3). In addition there areapproximately 87 000 reservoirs with a storage capacity of 413 billion m3.These form the main supply of drinking water as well as water for industrialand agricultural production and aquaculture. Because of a lack ofunderstanding of the frailty of lake ecosystems and poor environmentalawareness, human activities have greatly affected freshwater systems (Xie1995). The most marked impacts have been due to land reclamation,destruction of marginal vegetation, discharge of industrial, domestic andagricultural waste and irrational development and use of freshwaterresources. As a result lakes in dry areas are becoming saline, while othersare highly polluted and undergoing a process of rapid eutrophication. Themajority of the lakes tested to date have been classified as hypertrophic(Dokulil et al. 2000). Thus, although China has 28 of the world's largestlakes (Chang 1987, Chen 1994), the annual storage capacity ranks sixth inthe world and the per capita availability is a quarter of the world's average(Jusi 1989) and predicted to fall by the year 2000 (Shiklomanov 1993). Inthis article, we focus on the problems of one water supply reservoir

A general assessment of environmental and biological features of Windermere and their susceptibility to change

Bassenthwaite (Lake) is one of the larger Cumbrian lakes, certainly one of the most distinctive, and of considerable conservation and amenity value. Although its shores lack sizeable settlements, its main inflow receives sewage effluent from a major tourist centre (Keswick) and is subject to episodic floods. These influences, the growing development of leisure activities at the lake (e.g. sailing, time-share units), and recent road-construction, have led to past appraisals of ecological impacts and lake management. The lake has not been the subject of intense and long-term ecological study, but much scattered information exists that is relevant to future management decisions. In the present Report, commissioned by North West Water, such information - published and unpublished - is surveyed. Especial attention is given to evidence bearing on susceptibility to change, affecting the lake environment and its biota or species of conservation interest. Extensive use has been made of the results of a recent (1986-7) seasonal survey by the FBA

The phylogenetic position and ultrastructure of the uncultured bacterium Achromatium oxaliferum

Achromatium oxaliferum is a large, morphologically conspicuous, sediment-dwelling bacterium. Nothing is known concerning its phylogeny and it has eluded all attempts at laboratory cultivation. The limited physiological description of A. oxaliferum has been based on morphological features of the bacterium such as the presence of intracellular sulphur inclusions. A. oxaliferum cells were purified from a wetland region close to Rydal Water (Cumbria, UK). Scanning and transmission electron microscopy revealed that a number of morphologically distinct A. oxaliferum cell-types, based on cell surface features and the size and abundance of calcite and sulphur inclusions within the cells, were present in a single sample of purified cells. PCR was used to amplify almost full-length 16S rRNA gene sequences from DNA extracted from A. oxaliferum cells directly purified from sediments. The PCR products were cloned and partial sequences (approx. 400 bp) were determined for seven of the clones. Three different sequence clusters were recovered from the clone libraries. A near full-length (1489 bp) 16S rRNA gene sequence was determined for a representative clone of the most dominant sequence-type (52% of the sequences). Comparative sequence analysis showed A. oxaliferum to form a deep branching lineage within the γ-subdivision of the Proteobacteria. A. oxaliferum was related most closely to the Chromatium assemblage that includes sulphur-oxidizing symbiotic bacteria, purple sulphur bacteria, and sulpur- and iron-oxidizing thiobacilli. Phylogenetic inferences made using distance, parsimony and maximum likelihood methods all placed A. oxaliferum with this group of bacteria. Bootstrap support for a relationship with any particular lineage within the assemblage was weak. The seven clone sequences recovered from the A. oxaliferum cells however formed a monophyletic group well supported by bootstrap analysis (85-100% support depending on the analysis done). It was concluded that A. oxaliferum was related to organisms of the Chromatium assemblage but constituted a novel lineage within this group of bacteria. A. oxaliferum cells were confirmed as the source of the 16S rRNA sequence obtained, by the use of a fluorescently-labelled 16S rRNA-targeted oligonucleotide specific for the A. oxaliferum rRNA sequence