Finnish Environment Institute > Risk prediction for cyanobacterial blooms

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Risk of cyanobacterial blooms is considerable in Finnish sea areas this summer 2022-06-02

The cyanobacterial bloom risk is considerable in the Gulf of Finland, the Archipelago Sea and the southern parts of the Bothnian Sea. The risk this summer is at the same level as previous summers.

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As in the previous year, the risk of cyanobacterial blooms in the Finnish sea areas is considerable or moderate – the summer weather determines the actual situation 2021-06-03

The risk of significant and widespread cyanobacterial blooms this summer in the eastern Gulf of Finland and the main basin of the Baltic Sea is slightly higher than in summer 2020.

The risk of cyanobacterial blooms in the Finnish sea areas is considerable or moderate – the summer weather determines the actual situation 2020-06-04

In average summer weather conditions, the risk of algae is moderate in the northern part of the main basin of the Baltic Sea, a major part of the Archipelago Sea and in the southern part of the Bothnian Sea this summer. In the Bay of Bothnia and the eastern part of the Gulf of Finland, the risk is low.

Significant risk of blue-green algae blooms in summer across Finnish sea areas – warm and sunny summer may dramatically increase occurrence of blooms 2019-06-06

The risk of significant and widespread blue-green algae blooms in Finnish sea areas matches that of previous years, since the nutrient situation has remained largely the same. This summer brings with it a substantial risk of blue-green algae formations in the Gulf of Finland, the northern part of the Baltic Proper and most of the Finnish Archipelago Sea. The weather conditions will determine whether or not the risk is realised.

The risk of significant blue-green algae blooms in summer 2018 is lower than earlier years in Finnish marine areas 2018-06-07

The risk of widespread blue-green algae blooms in Finnish sea areas is less than during the last two years, because the algae have less nutrients available in comparison to previous years. However, significant algae blooms may form in the Gulf of Finland if the summer is warm. A warm May could cause blooms to occur earlier than normal this year.

Significant blue-green algae blooms possible in Finnish marine areas during 2017 summer 2017-06-01

The risk for vast blue-green algae blooms in the Gulf of Finland is greater than during previous years. The exceptional nutritional conditions are caused partially by major Baltic inflows from the North Sea in 2014 and 2016, which allowed the phosphorous deepwater to reach the Gulf of Finland. In addition, the lack of winter ice and the windy winter mixed the water layers and brought nutrition to the surface layer of the Gulf of Finland.

Considerable risk of blue-green algal blooms in some of Finland's sea areas in the summer of 2016 2016-06-02

According to the estimate of the Finnish Environment Institute’s Marine Research Centre, this year the risk of blue-green algal blooms is considerable in a large part of the Gulf of Finland, the Finnish Archipelago Sea and the northern part of the Baltic Sea's main basin. In the central and southern parts of the Bothnian Sea and the eastern Gulf of Finland the risk is moderate. In the northern part of the Bothnian Sea and the Bothnian Bay the risk is low.

Algal forecast: considerable risk of blue-green algal blooms in some of Finland's sea areas 2015-06-05

According to the algal forecast from SYKE’s Marine Research Centre, the risk of blue-green algal blooms is considerable in the entire western Gulf of Finland, the southern areas of the Finnish Archipelago Sea and the northern part of the Baltic Sea's main basin. In the southern parts of the Bothnian Sea and the eastern Gulf of Finland the risk is moderate. In the Bothnian Bay, the northern parts of the Bothnian Sea and in the easternmost part of the Gulf of Finland the risk is low.

Algae prognosis: considerable risk of blue-green algal blooms in some of Finland's sea areas 2014-06-05

According to the algae prognosis from the Finnish Environment Institute’s Marine Research Centre, the risk of blue-green algal blooms is moderate in the western part of the Gulf of Finland, the Finnish Archipelago Sea, and the southernmost parts of the Bothnian Sea. In the southern parts of the Finnish Archipelago Sea and the northern part of the Baltic Proper, the risk of algal blooms is considerable. The risk of algal blooms is greatest in the western parts of the Baltic Proper.

Algae prognosis: low or moderate risk of blue-green algal blooms in Finland's sea areas 2013-06-06

According to the algae prognosis of the Finnish Environment Institute’s Marine Research Centre, the risk of blue-green algal blooms in Finland's sea areas is mainly low this summer. In the western Gulf of Finland, the southern reaches of the Archipelago Sea, and in the north-eastern parts of the Baltic proper, there is a moderate risk of algal blooms. No major blooms are forecast in the Gulf of Bothnia. The southern Baltic Sea faces the greatest risk of blue-green algal blooms.