Evaluating the effects of nutrient load reductions on the biomass of toxic nitrogen-fixing cyanobacteria in the Gulf of Finland, Baltic Sea

• Published in: Boreal environment research Vol. 6; no. 2; pp. 131 - 146
• Main Authors: KIIRIKKI, Mikko, INKALA, Arto, KUOSA, Harri, PITKÄNEN, Heikki, KUUSISTO, Minna, SARKKULA, Juha
• Format: Journal Article
• Language: English
• Published: Helsinski Finnish Environment Institute 2001
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Baltic Sea, Finland Gulf; Biological and medical sciences; Earth sciences; Earth, ocean, space; Exact sciences and technology; External geophysics; Fundamental and applied biological sciences. Psychology; Geochemistry; Mineralogy; Physical and chemical properties of sea water; Physics of the oceans; Russia, St. Petersburg; Sea water ecosystems; Silicates; Synecology; Water geochemistry; Northeast Atlantic; North Atlantic; Gulf of Finland; Scandinavia; Baltic Sea; Finland; ANE, Baltic Sea, Finland Gulf; sea water; impact statements; biomass; bacteria; Europe; Atlantic Ocean; nitrogen; Plantae; algae; digital simulation; nutrients; prokaryotes; modern; hydrochemistry; Cyanophyta; ecosystems; three-dimensional models; phytoplankton; plankton; Thallophyta; phosphorus
• ISSN: 1239-6095

The effects of nutrient load reductions on the biomass of N-fixing cyanobacteria were evaluated in the scale of the Gulf of Finland. The two analysed reduction scenarios were Finnish national agenda and the improvement of phosphorus removal in the present purification plants of St. Petersburg. The effects of load reduction scenarios were tested by using a 3D-ecosystem model with a horizontal resolution of 5 km. According to the results the Finnish national agenda cannot decrease the biomass of N-fixing cyanobacteria, but it seems to be able to reduce the total phytoplankton biomass in the coastal waters. The phosphorus reduction in St. Petersburg decreases the N-fixing cyanobacteria significantly in the central parts of the Gulf of Finland. Improvement of the phosphorus purification efficiency in the present sewage treatment plants offers us an opportunity to try to control the intensity of the toxic blooms of nitrogen-fixing cyanobacteria in the scale of the Gulf of Finland.