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Monitoring of Long Term Trends

Environmental monitoring reveals long term changes

During the last 40 years, the water quality of the Helsinki coastal sea area has changed markedly. The changes are due to shifts in human activities in the area and due to larger scale environmental changes, including climate change.

Both surface- and near bottom water temperatures have increased by approximately two degrees since the 1970’s. Simultaneously salinity has decreased, which affects the distribution of many organisms in the area. These changes can also be seen elsewhere in the northern Baltic Sea and the decrease of salinity has been predicted to continue as the climate change proceeds.

Changes in the treatment process of municipal waste waters is the single largest factor influencing the amount of nitrogen present in the coastal sea of the Helsinki metropolitan area. For near bottom waters, changes in total phosphorus concentrations are again caused by the internal loading of phosphorus from sediments. The internal loading of phosphorus is one symptom of eutrophication, as is the increasing turbidity of the water along with an increasing amount of planktonic algae.

Since the 1970’s, as the amount of algae has grown surface waters have become more turbid. After 2010 surface waters have become slightly clearer again, along with decreasing nutrient concentrations. However, near bottom water turbidity has continuously increased, as of yet because of unknown reasons.

Taking into account long term changes in protection and planning of the marine environment is important. This way one can with confidence evaluate short term effects of different operations and take into account the marine environment when planning the use of coastal areas. It is also of importance to make sure that current operations and developments do not weaken the status of the coastal sea area.

Figures depicting long term changes can be downloaded in pdf-format to be used in presentations or as back ground information from the links on the right. Further information can be requested from the City of Helsinki Environment Centre.

Based on the long term monitoring data sets and annual ecological quality assessment is made for the coastal area of the Helsinki metropolitan area. A map of the latest assessment can be downloaded from a link on the right.

The variation and long term trends in the parameters depicting changes in the ecological quality of the coastal sea area have been analyzed by fitting a statistical model (GAM) to the summer month (June-September) means of all observations. The figures are updated annually.

 

lämpötila
Temperature
suolapitoisuus
Salinity
typpi
Nitrogen
fosfori
Phosphorus
sameus
Turbidity
klorofylli a
Chlorophyll-a

Monthly means of summer time (June-September) surface water (0-10 m) temperature, salinity, total nitrogen, total phosphorus, turbidity and chlorophyll-a for all monitoring stations located in the coastal sea area of the Helsinki metropolitan area. A statistical model (GAM) fitted to the monthly means and the model 95% confidence intervals are presented. Click figures to enlarge.

 

lämpötila
Temperature
suolapitoisuus
Salinity
typpi
Nitrogen
fosfori
Phosphorus
sameus
Turbidity
klorofylli a
Oxygen


Monthly means of summer time (June-September) near bottom water (bottom +1 m) temperature, salinity, total nitrogen, total phosphorus, turbidity and oxygen for all monitoring stations located in the coastal sea area of the Helsinki metropolitan area. A statistical model (GAM) fitted to the monthly means and the model 95% confidence intervals are presented. Click figures to enlarge.



06.12.2019 18:40

Sea water temperature and amount of algae

The water quality and the state of the sea area is monitored biweekly through water samples and various measurements