Benthic foraminifera assemblages as elemental pollution bioindicator in marine sediments around fish farm (Vrgada Island, Central Adriatic, Croatia).
Effects on sediments of fish farming activity near Vrgada Island was analysed through living and total foraminiferal assemblages and concentration of major, minor and trace elements from three sediment cores. Elemental concentrations of sediments are in accordance with carbonate characteristics of the surrounding area and show mostly natural element variations between sampling locations and throughout the cores, with no significant increases due to fish farming activity. Only phosphorus concentration shows elevate values below the fish cage, assigned to fish pellets. Foraminiferal communities are dominated by epifaunal and stress tolerant species, while diversity indices point to normal marine conditions. The type of substrate and phosphorus content in sediments principally influence foraminiferal community composition, while other elemental concentrations have no perceptible effect on the assemblages. Some foraminiferal species Ammoniatepida, Ammoniabeccarii, Elphidiumcrispum, Elphidiummacellum and genus Haynesina are confirmed to be tolerant to elevated nutrient (phosphorus) content, while Ammonia parkinsoniana shows sensitivity to pollution. Postmortem processes cause decrease of foraminiferal density and species richness with core depth. All results point to negligible influence of fish farming and relatively stable environmental conditions at all sampling locations.
Department of Geology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia.
Jelena
J
Vidović
Depatment of Geology, Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva 12, 1000 Ljubljana, Slovenia.
Matej
M
Dolenec
Depatment of Geology, Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva 12, 1000 Ljubljana, Slovenia.
Tadej
T
Dolenec
Dalmar d.o.o. company, Jadranska cesta 4, Pakoštane, Croatia.
Vatroslav
V
Karamarko
Depatment of Geology, Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva 12, 1000 Ljubljana, Slovenia. Electronic address: petra.zvab@guest.arnes.si.
Petra
P
Žvab Rožič
D000818:Animals; D017756:Aquaculture; D044822:Biodiversity; D017523:Croatia; D004784:Environmental Monitoring / Q000379:methods; D005399:Fishes; D056908:Foraminifera; D019015:Geologic Sediments / Q000737:chemistry / Q000469:parasitology*; D010758:Phosphorus / Q000032:analysis; D025341:Principal Component Analysis; D014131:Trace Elements / Q000032:analysis; D014877:Water Pollution, Chemical / Q000032:analysis*
D014131:Trace Elements; D010758:Phosphorus
Adriatic Sea; Fish farm; Foraminifera; Major minor and trace elements; Nutrients; Sediment