Dr Melissa Carew  Research Fellow

Chironomids are a common and diverse group of aquatic insects. Many chironomid larvae live in aquatic sediment where they are exposed to accumulating pollution. Chironomid species have different levels of sensitivity to sediment pollution and the occurrence of particular chironomid species at a site can reflect the impact from pollution. This makes chironomids useful tools for the biological monitoring of urban streams, rivers and wetlands. However, we still need to understand ecological requirements and pollutant sensitivities of many species, and also develop a means to rapidly and accurately identify chironomid species.

My research has involved developing a DNA marker system to rapidly identify chironomid species from around the greater Melbourne area, and identifying the habitat requirements and pollution sensitivities of chironomids through intensive sampling of wetlands around Melbourne. Four surveys of wetlands have been conducted in the Melbourne area and species markers were developed for over 80 different taxa using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the mitochondrial cytochrome oxidase I (COI) region. In 2007, this work was furthered by including chironomids collected from Melbourne streams. The project has established several putative indicator species of sediment pollution and salinity. Patterns of seasonal and temporal abundance and specific habitat requirements of different species have been established. The project is providing information vital for the successful use of chironomids as biological indicators.