Increasing amounts of dark-coloured carbon compounds that originate from catchment areas flow into the Arctic and northern lakes. They alter resource utilization and community structure of macroinvertebrates, says MSci Henriikka Kivilä in her doctoral thesis in aquatic sciences at the University of Jyväskylä. Long-term sediment records also revealed that in addition to surface flow, nutrients of marine origin may have a significant role in the future of the Arctic coastal lakes.