Mussel fouling of the technical construction in the inner part of the Sevastopol Bay (the Black Sea)

Abstract

The research of the fouling on the water intake pipe of Sevastopol heat and power station is able to get more information to plan replacement of artificial objects in the Sevastopol bay, taking into account their potential biopositive properties. The mytilids fouling on the metal pipe was presented only by mussels. The abundance of mollucks varied with depth and, in dependence of the water exchange. On the inside of theconstruction the mussels quantity was 448 ind.·m⁻², and biomass 948 g·m⁻². On the outer surface at the lower horizon the number was 352 ind.·m⁻² and biomass 4627 g·m⁻², and 224 ind.·m⁻² and 1890 g·m⁻² at surface horizon. The biofilter capacity reaches the minimum values the inside of pipe – 463 l·day⁻¹·m⁻². On the outer surface of the structure at the top its value was 555 l·day⁻¹·m⁻² and on the deep part – 1574 l·day⁻¹·m⁻². It is shown that even in the inner regions of the Sevastopol Bay (where documented elevated levels of pollutants and the intensification of the self-purification processes is urgent) the abundance of mytilids fouling is raising with depth. This leads to a more effective biofilters. Comparing of mussel fouling on the inner and outer parts of the water intake pipe shows that already at 0.5 m from of its tip habitat conditions for mussels significantly worse than on the surface, which is washed by the bay waters. As a result, the biomass of molluscs and as a consequence the filtration capacity of the settlement is reduced. On this basis, the design of biopositive constructions must take into account that in the case of a vertical orientation, the depth of the niches should be small enough to allow good water exchange inside it to be sufficient to create the most comfortable living conditions for shellfish filter-feeders.

Keywords: biopositive constructions, artificial substrate, mussels, biofilter, Sevastopol bay, Black Sea