Use of diatoms to monitor nutrients in rivers / M.G. Kelly and B.A. Whitton.
By: Kelly, M. G.
Contributor(s): Whitton, B. A | National Rivers Authority.Material type: BookSeries: R & D note: no. 431Publisher: Bristol, U.K. : National Rivers Authority, 1995Description: 66 pages ; 30 cm.Subject(s): FRESHWATER DIATOMS | ECOLOGY | TROPHIC STATUS | EUTROPHICATION | NUTRIENTS | MONITORING | RIVERS | SEWAGEHoldings: GRETA POINT: 574.6.08 KEL
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Research contractor: Durham Univ. (GB).
Contents -- List of Tables -- List of Figures -- List of Boxes -- List of Abbreviations and Acronyms -- Summary & Keywords -- 1. INTRODUCTION -- 2. METHODS -- 2.1 Environmental measurements -- 2.2 Biological methods -- 2.3 Data analysis -- 3. DEVELOPMENT OF TROPHIC DIATOM INDEX -- 3.1 Rationale -- 3.2 Method -- 3.3 Taxon weightings -- 3.4 Testing the TDI -- 3.5 Use of index -- 4. CASE STUDY: RIVER KENNET -- 4.1 Introduction -- 4.2 Study sites and sampling programme -- 4.3 Results -- 4.4 Discussion -- 5. CASE STUDY: UPPER COQUETDALE -- 5.1 Introduction -- 5.2 Study sites and sampling programme -- 5.3 Results -- 5.4 Conclusions -- 6. CASE STUDY: RIVER BROWNEY -- 6.1 Introduction -- 6.2 Study sites and sampling programme -- 6.3 Results -- 6.4 Discussion --7. DISCUSSION -- 7.1 Use of trophic diatom index -- 7.2 Practical aspects of sampling lowland Rivers -- 7.3 Conclusions: the value of diatoms to the NRA -- 8. REFERENCES -- APPENDIX 1: List of “Clean” Sites Used to Derive Trophic Diatom Index.
1. A diatom index for monitoring the trophic status of rivers (“trophic diatom index”, TDI) has been developed, in response to the needs of the Urban Wastewater Treatment Directive. This is based on a suite of 86 taxa selected both for their indicator value and ease of identification.
2. When tested on a dataset of 71 sites free of significant organic pollution, this index was more highly correlated with aqueous phosphorus concentrations than existing diatom indices. However, where there was heavy organic pollution, it was difficult separate the effects of eutrophication from the other effects of organic pollution. For this reason, the value of the TDI is supplemented by an indication of the proportion of the sample that is composed of taxa tolerant to organic pollution.
3. This index was tested in three intensive studies on the River Kennet (Wiltshire, Berkshire), streams in Upper Coquetdale (Northumberland) and River Browney (Co. Durham). These demonstrated how it could be used for practical monitoring and also highlighted some potential problems.
4. TDI can be used in reconnaissance surveys to identify sensitive areas (eutrophic). The study on the River Kennet is an example of this: this demonstrated that the river was eutrophic above the first “qualifying discharge” (Newbury STW) and it is suggested that nutrient inputs upstream need to be controlled before nutrient stripping at this works is likely to be effective.
5. The other intensive studies involved repeated sampling at four sites (2 upland, 2 lowland) to examine changes in diatom community structure over time. These demonstrated an interplay between physical and chemical factors. Interpretation of unexpected effects (e.g. abundant Nitzschia at upland sites) can lead to new insights into water quality.
6. It may be necessary to sample semi-permanent artificial substrates, fixed structures and macrophytes at some lowland rivers where there are few boulders in situ.
7. The index is recommended for widespread use by the NRA and other regulatory bodies alongside other tools currently used to assess the trophic status of rivers and streams.
GRETA POINT: 574.6.08 KEL