Nitrogen and phosphorus as production limiting factors in the estuarine waters of the eastern Gulf of Finland

Abstract

The data originated from five cruises performed in 1990-1992 and include CTD measurements and spatial distributions of different nutrient fractions as well as nutrient depletion measurements onboard. The results revealed quick losses of both total and inorganic nutrients from the euphotic layer of the inner estuary under varying physical conditions. In general the inner estuary was P limited, while the open eastern gulf was mainly N limited. In the outer estuary low mixed layer depth (MLD) favoured N limitation, while thick MLD (ie windy weather) favoured P limitation. This indicates that reduction of both N and P load into the eastern Gulf would improve water quality in this area. However, effective N removal wuld probably induce the most extensive improvement in the trophic status of the entire Gulf of Finland. -from Authors