Líffræðifélag Íslands
Líffræðiráðstefnan 2015

Erindi/veggspjald / Talk/poster V1

Biomass and species assemblage structure of algae in Hlíðardalslækur, a geothermally affected stream, NE Iceland.

Sigurður Óskar Helgason, Jón S. Ólafsson, Gísli Már Gíslason and Paula C. Furey

Veiðimálastofnun, Háskóli Íslands

Kynnir / Presenter: Sigurður Óskar Helgason

Tengiliður / Corresponding author: Sigurður Óskar Helgason (soh47@hi.is)

Until recently, few studies have been made on geothermal ecosystems in Iceland. Over the past few years studies concerning geothermal ecosystems have been rapidly growing, especially in the field of microbes and later on, ecology and classification. This study aims to assess the effect from the geothermal power utilization Kröflustöð, on-biota in the stream ecosystem in Hlíðardalslækur. Algal and macroinvertebrate species assamblage structure and biomass will be sampled bimonthly for a year above and below the Krafla geothermal power station and a reference site in a nearby warm spring-fed stream. Simultanerously, several environmental parameters will be collected, including: pH, temperature with data loggers, conductivity, the streams flow rate and major nutrients as well as major ions. The effects of nutrient inputs on benthic algal assemblages will also be experimentally assessed using both tiles and nutrient-diffusing substrata. We predict that algae assemblage structure varies greatly between study sites, and that biomass decreased below the Krafla geothermal power station. Higher algal biomass occurred in July compared to June and September. Green algae and cyanobacteria dominated all streams but biomass between green algae, diatoms and cyanobacteria varied greatly between sampling sites. Biomass between groups of algae did not show significant changes over the observed period. Biomass based on ash-free dry mass, reached maximum values at three sampling sites in July and three sampling sites in September. The most common genera of algae in the observed stream are Cyanobacterias (Anabaena sp, Spirogyra sp, Lyngbya sp, Oscillatoria sp) and the Chlorophyta Cladophora sp.