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Heavy nutrient and organic matter loading, resulting in enhanced primary productivity, is currently recognised as the most serious environmental problem for the Neva Estuary and adjacent parts of the eastern Gulf of Finland. The introduction of alien species is an emerging issue for the Neva Estuary and should seriously be taken into account, considering the rapid development of the shipping industry in the area. These environmental problems along with the prevailing strategy of transport-oriented development of the coastal zone in the Neva Estuary and insufficient legislative background are the main challenges for coastal zone management in the eastern Gulf of Finland. The development of comprehensive management plans could serve as an essential step toward effective coastal zone management in the Neva Estuary and adjacent areas. Management approaches to control eutrophication in the Neva Estuary coastal zone should consider the development of filamentous algae mats and emergent macrophytes in the littoral zone as the most appropriate indicator of the ecosystem state and measure of effectiveness of management actions. Management actions should be based on the scientific knowledge of the main factors controlling the development of filamentous algae, which needs further research. The management of the introduction of alien species requires different approaches and should mainly be based on preventive actions, including ballast-water control.

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Structural and functional characteristics of macrobenthic animal communities have been studied in several rivers and lakes. Shannon diversity index (a) has been used as a measure of animal community structure. Relation of community production (Pb) to metabolic rate of all animals in the community (Rb) was regarded as its functional characteristic. Quantitative relations between structural and functional characteristics of aquatic animal communities have been established. The work deals with steadiness and stability and complexity of aquatic animal communities with regard t o their structural and functional characteristics. For a better understanding of possible changes in communities brought about by human impact a notion of community durability is introduced, which means their ability t o resist environmental changes maintaining their structure and functions.