@misc{Wiktor_Krystyna_Zmiany_1975,
 author={Wiktor, Krystyna},
 editor={Polska Akademia Nauk. Komitet Ekologiczny},
 copyright={Creative Commons Attribution BY 3.0 PL license},
 address={Warszawa},
 howpublished={online},
 year={1975},
 language={pol},
 abstract={Attention has been drawn in this paper to the resu lts of the progressiveeutrophication of the Baltic Sea due to the increasing in flux of biogenetic substances (chiefly phosphorus) from the land (Figs 2 and 4).Progressive eutrophication brings about an increase in biological productivity,manifested in this body of water in successive trophic levels (Fig. 1). The effectof this state of affairs is also increase in fishing productivity (Tab. 1). Thisphenomenon is accompanied by simultaneous changes in the structure of groups(Tab. II), which in certain cases are extremly unfavourable to the whole biocenosis(e.g. the increasing blooming from year to year of blue-green algae, this includingMicrocystisae ruginosa , a species with metabolites exerting a toxic effect).The increase in the degree of eutrophication of the Baltic Sea is also linkedwith the more intensive accumulation of organic substances on the bottom andthe layers of water near the bottom which — with the increasing difficulty ofoxygen access to these layers — leads to intensification of oxygen deficit andconstant , although slow, extension of azoic zones (Figs 2 and 3).Taken generally it must be emphasised that despite the apparently favourableeffect of the increase in biological productivity observed at the present time, theresults of progressive eutrophication of the Baltic Sea may be equally as dangerousto these waters as the results of the effects exerted by pollution of a differenttype (extension of azoic zones, changes in the structure of groups ichtiofauna etc.,which are unfavourable from the economic point of view).The most important, although simultaneously very difficult, task to becarried out in order to prevent continuation of the eutrophication process wouldbe to limit the influx of phosphorus into the Baltic.},
 title={Zmiany w produktywności biologicznej Bałtyku jako efekt postępującej eutrofizacji},
 type={Text},
 URL={http://www.rcin.org.pl/Content/147278/PDF/WA058_107164_P3259-21_Eko-Pol-B.pdf},
 volume={21},
 number={2},
 journal={Wiadomości Ekologiczne},
 publisher={Państwowe Wydawnictwo Naukowe},
 keywords={biological productivity, Baltic Sea, eutrophication},
}