Rapport nr 79: Säsongsvariationer i hydrografi, näringsämnen och klorofyll a i ett åländskt skärgårdsområde
ÅDJERS, K; BACKLUND, C (1992)
ÅDJERS, K
BACKLUND, C
Åbo Akademi, Husö biologiska station
1992
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Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:951-650-064-1
https://urn.fi/URN:ISBN:951-650-064-1
Tiivistelmä
Hydrography, nutrient and chlorophyll a contents were investigated in an archipelago gradient (inner to outer) during one year on the northwestern Åland Islands. The gradient possesses increasing water transparency and salinity and decreasing nutrient loading. The inner and middle archipelago zones showed disturbed seasonal variation of nutrient contents while the outer archipelago appeared to be in an undisturbed condition. The decreasing nutrient loading in the gradient was confirmed by decreasing nutrient and chlorophyll a contents in the water column. The waterbody mainly appeared to be nitrogen limited with the exception in the vinter in the inner and middle archipelago, when indications of phosphorus limitation occurred. The middle zone was obviously affected of effluents of nutrients and organic material from a fish farm. The outer archipelago zone can be regarded being on the borderline between oligotrophic and mesotrophic and the rest of the area as mesotrophic, except the innermost part, which can be classified as eutrophic. The conclusion is that the outer archipelago zone does not suffer from local human activities and therefore is well suited as a reference area even on an international level.