Aquatic insects larvae as water quality indicators

Abstract

Biomonitoring je korištenje živih organizama ili njihovog odgovora na okolišne promjene za određivanje kakvoće okoliša. Strukture zajednica slatkovodnih organizama u svrhu biomonitoringa koristite se od početaka 20 st. Za razliku od kemijske, biološka analiza kakvoće vode je jeftinija i ukazuje na prosječnu kakvoću vode u dužem razdoblju. Njezini su nedostaci nemogućnost određivanja vrste i količine određene zagađujuće tvari. Akvatičke ličinke kukaca praktične su za utvrđivanje kvalitete vodenih tijela jer često sačinjavaju i preko 70 % akvatičke faune. Ističu se predstavnici skupina Ephemeroptera, Plecoptera i Trichoptera (EPT) kao osjetljive svojte čija je prisutnost i brojnost u izravnoj vezi s mnogim stresorima. Posebice smanjenjem količine kisika i brzine strujanja vode što ih čini dobrim pokazateljima organskog onečišćenja i hidromorfološke degradacije. Iako biomonitoring pomoću akvatičkih ličinki kukaca ima svoje značajne prednosti, za dobivanje potpune slike kvalitete vode nekog vodnog tijela preporučljivo je u sprezi koristiti i biomonitoring temeljen na drugim skupinama organizama kao što su dijatomeje i ribe, te mikrobiološke i kemijske analize.Biomonitoring can be defined as using living organisms, or their responses to environmental changes, to assess the quality of the environment. First noted use of freshwater communities in biomonitoring is known from early 1900´s. Opposite to chemical methods, biological analyses are cheaper and provide insight to average water quality during longer time intervals rather than the current (acute) state. Its deficiencies are inability to provide information on quality and quantity of specific pollutant. Aquatic insects larvae often contribute to aquatic fauna with more than 70%, which makes them suitable to use in water quality analyses. Species of insect orders Ephemeroptera, Plecoptera and Trichoptera (EPT) are well known for their presence and abundance in correspondence with various stressors in the environment, especially oxygen deficiency and reduction of flow intensity. These properties make them good indicators of organic contamination and hydromorphological degradation. Although biomonitoring based on aquatic insects larvae has its advantages, it is recommended to use it in combination with analyses based on other organisms groups, such as diatoms and fish and microbiological and chemical analyses, to get a complete picture of water quality