Ecological Risks Perspectives from Poland and the United States (1990) / Chapter Skim
Currently Skimming:
Assessment of Trophic Impact on the Lake Environment in Poland: A Proposal and Case Study
Assessment of Trophic Impact on the Lake Environment in Poland: A Proposal and Case Study
Pages 283-296
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 283... ...
The specific aims of environmental assessment are: · to predict impacts over short and long time periods, with special emphasis on situations in which disturbances are irreversible under real technical and economical conditions; and · to assess accurately the stimulus/response relationship and to indicate the kind of protective measures and/or treatment to be undertaken. The proposed assessment system discussed below concerns trophic impacts on a lake ecosystem and the process of eutrophication as the response of its biota to nutrient loading.
|
From page 284... ...
Specifically, it assesses: . trophic impact in terms of phosphorous nutrient loading from external sources; · impact of the watershed on the sources and transport of nutrients; · natural resistance of lakes to trophic and pollution impacts; and - · responses of biological communities and basic ecological processes in the lake ecosystem across increasing intensities of trophic impacts.
|
From page 285... ...
When the actual annual TP load (i.e., total input from sewage, runoff, precipitation, and tributaries) is below permissable levels according to Vollenvieder's (1976)
|
From page 286... ...
would be watersheds with very high values for at least three or four parameters, such as density gradient, ratio of watershed to lake surface, mean slope, and an area covered by sandy substratum without clay intrusions and at least 10% arable and/or urban areas in the lake watershed.
|
From page 287... ...
ASSESSMENT OF NATURAL RESISTANCE OF IAKES TO TROPHIC IMPACI Nutrient loading of comparable intensity will produce different effects in lakes with different morphometry and turnover rates. ~ assess these conditions, four categories of lake resistance (CatLR)
|
From page 288... ...
THE ECOLOGICAL RESPONSE OF LAKES TO TROPHIC IMPACT Research was carried out on about 50 Masurian lakes (including the Great Masurian Lakes) to evaluate trends and magnitudes of changes in lake ecosystems along the trophic continuum and under known conditions of P- loading (Kajak, 1983; Zdanowski et al., 1984~.
|
From page 289... ...
The extreme values of these parameters and indices usually occur in D-3 lakes and/or in P-2 and P-3 lakes which are the most eutrophic and hypertrophic deep and shallow lakes. The above three trophic classes of lakes are compatible with the four classes of lake water quality (ClaWQ)
|
From page 290... ...
290 ECOLOGICAL RISKS TABLE 4 Lake quality evaluation system in Poland using water purity indices for three classes of lake water (n = stratified; ns = non-stratified lakes)
|
From page 291... ...
ASSESSMENT OF TROPHIC IMPACT ON LAKES IN THE MASURIAN I~NDSCAPE PROTECTED AREA AND SOME PROPOSALS FOR THEIR PROTECTION The assessment systems cited above are intended for use in scientific management and were applied to lakes situated in a protected area of about 700 km2 in the Lake District in Poland known as the Masurian Landscape Protected Area (Figure 1~. This area was established in 1977 to protect the land forms, forest complexes, marsh and bog habitats, rivers, and lakes of the postglacial Masurian landscape.
|
From page 292... ...
Only one deep lake (Lake Mokre) receives an annual TP load within permissible limits (CatEND 2)
|
From page 293... ...
Based on these findings, three principal methods of protection and management were proposed to maintain the actual status of some of the lakes and to control the further eutrophication and hypertrophication of others (Figure 3~. For the central part of the area around Lake Mikolajskie and Lake Beldany, a program of lake restoration was proposed utilizing deep water aeration, inactivation of TP internal loading, and diversion of principal point sources of pollutants (Figure 3~.
|
From page 294... ...
for lakes and watersheds in Masunan Landscape Protected Area (Bajkiewicz-Grabowska, 1987~. which the deep mesotrophic Lake Mokre and other mesotrophic shallow lakes are located special protection of watersheds and lakes was established to preserve their actual state, including control of fishing operations and a ban on the introduction of planktivorous fishes.
|
From page 295... ...
CONCLUSION Eutrophication remains the primary cause of anthropogenic disturbances of natural lakes and their environments, even after the elimination of point sources of nutrient inputs. It is also the primely cause of changes in the numerous small- and medium-sized natural lakes situated in arable regions (e.g., the North European postglacial lakelands)
|
From page 296... ...
1981. Nonpoint sources of nutrients to the lake watershed of river Jorka, Masurian Lakeland, Poland.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.