Trophic structure of the fouling community in Odessa Bay (Black Sea)

Abstract

The trophic structure of the coastal fouling community of Odessa Bay (Black Sea), which was composed of 10 species of macrophytes, 57 invertebrate species and 4 species of fish, was determined. The basic trophic relationship between organisms composing the community is shown. A minimization of interspecific trophic competition within the community is noted. The main sources of food material entering the fouling community were determined. We show that a significant proportion of food in the form of detritus, dissolved organic matter and small planktonic organisms enters the community from the water column. Filtration and pumping activity of sestonophage-organisms, particularly mussels, helps to attract food material to the community. Primary producers of the community are macrophytes and microphytes, which develop on account of their photosynthetic activity and ensure the provision of food to herbivores. The trophic group of detritophages consumes different fractions of the detritus which accumulates in the byssus threads of bivalve molluscs. In this context, mussel druses act as sediment traps, collecting detritus. Numerous polyphages, which are essentially omnivores and do not usually lack food material, were noted in the community. A small group of carnivorous invertebrates, whose representatives actively attack small animals, was identified. The abundance of these species in the community was about 1%, and their biomass less than 0.6%. Fish living in macrophyte weeds are the consumers in the community. We determined that the highest relative abundance (over 36%) in the fouling community was reached by sestonophages and polyphages. We found that the undisputed leader in the relative biomass (over 97%) in the fouling community ofOdessaBaywas the sestonophages (mainly composed of mussels). We determined that the trophic structure index of the community was 0.94, which confirms the significant dominance in biomass of bivalves over other species in the fouling community.

Хорологічна структура прибережного угруповання обростання, що формується чорноморською мiдiєю Mytilus galloprovincialis

“…Прикріплюються мідії до субстрату за допомогою своїх бісусних ниток, в результаті чого передні частини їх черепашок щільно стикаються один з одним. Внаслідок цих структурних особливостей мідієвих друз відносно доступними для осідання личинок інших безхребетних залишаються тільки задні частини черепашок молюсків (Varigin 2016 Як видно з отриманих даних, у верхній частині траверса в більшості випадків були зосереджені молоді молюски, а в нижнійдорослі. Так, у верхній частині траверса максимальна довжина мідій не перевищувала 50 мм.…”