Planned object

Title: Eutrophication rate of lakes in the Jorka river system (Masurian Lakeland, Poland): long-term changes and trophic correlations


Hillbricht-Ilkowska, Anna

Date issued/created:


Resource Type:



Eutrophication of lakes - long-term changes


Polish Academy of Sciences. Institute of Ecology


Polish Academy of Sciences. Institute of Ecology. Publishing Office

Place of publishing:

Dziekanów Leśny


Pages 475-487 : illustrations ; 27 cm ; Bibliographical references (pages 486-487)


No trends were found in longterm variation (between the 1970s and the 1990s) of basic trophic parametres (TP,TN, chlorophyll concentration, algal biomass, and water transparency) in five lakes of the river-lake system typical of a lakeland. hilly area (the Jorka river system, Masurian Lakeland). Recently, this lake chain maintains the historically developed trophic differentiation between deep, mesotrophic lake close to headwaters and shallow, eutrophic lake close to the outlet of the river. The only change found is the replacenemt of cyanobacteria dominating in the 1970s by dinoflagellates dominating in the 1990s. A strong correlation was found between TP loading to lakes and in-lake TP concentration in spring periods, however no correlation existed between TP and other trophic indices. On the other hand, the interrelations between SO, chlorophyll, and algal biomass were highly significant in summer periods and marginally significant in spring periods. This pattern was also found in other groups of lakes in the region. It is concluded that in hilly lakeland region, the river-lake systems draining small mosaic catchments are resistant to the further eutrophication (low nutrient loading, no point sources) and for this reason they tend to maintain the trophic conditions developed in the remote past.


Polish Journal of Ecology





Start page:


End page:


Resource Identifier:

ISSN 1505-2249


MiIZ PAN, call no. P.2840 ; click here to follow the link



Language of abstract:


Creative Commons Attribution BY 3.0 PL license

Terms of use:

Copyright-protected material. [CC BY 3.0 PL] May be used within the scope specified in Creative Commons Attribution BY 3.0 PL license, full text available at: ; -

Digitizing institution:

Museum and Institute of Zoology of the Polish Academy of Sciences

Original in:

Library of the Museum and Institute of Zoology of the Polish Academy of Sciences

Projects co-financed by:

Operational Program Digital Poland, 2014-2020, Measure 2.3: Digital accessibility and usefulness of public sector information; funds from the European Regional Development Fund and national co-financing from the state budget.

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