Benthic insect egg and larvae development in High Arctic streams, RiS ID 10448

Aquatic ecosystems in High Arctic environments and their benthic communities are due to worldwide environmental changes strongly influenced by rising air and water temperatures, enhanced glacier melting, oscillating discharge dynamics and an extended snow free season. But little is known about the cause effect relationship and the current situation regarding benthic insect life cycles and community structure. For the first time this project investigates the egg and larval development, growth and emergence of key chironomid species in three different stream types on Svalbard. During two field trips in 2016 (July and September) to Bayelva (glacier fed), Londonelva (spring fed) and Stuphalletelva (rain and snow fed, nutrient enriched by seabird colony) the three streams will be extensively sampled at least two times per occasion. Thereby five Surber samples (immediately fixed with 75% ethanol), discharge, water temperature, water chemistry, water and periphyton organic matter and chlorophyll a content will be taken each time. Additionally fertilized female adults will be caught with a sweep net, transported live to the laboratory and kept separately for controlled egg deposition. The egg masses will be divided and reared at four different temperatures (2, 4, 8 and 12) in the laboratory in order to simulate natural environmental conditions and climate change effects. The fixed larvae from the Surber samples will be identified to species level and morphometrically measured (overall body length, width and height of the fourth body segment as well as head capsule width and length). In this way the whole benthic life cycle ?from the egg to the latest larval instar- will be decoded for the first time, giving new insights to High Arctic benthic community dynamics and development processes.