Planktonic algae are the most abundant photosynthetic organisms. They are the basis of the marine food web, and changes in phytoplankton communities generally provide an early indication for climate-driven modifications of marine food webs and the whole ecosystem. Harmful algal blooms (HAB) are a subset of planktonic algal species that have negative impacts on humans and aquatic environments. The formation of HABs depends on several multifactorial climate and environmental drivers that influence timing and frequency of these algal blooms. There is some evidence that the occurrence of HAB might become more intense, widespread, frequent and unexpected in future decades due to climate variability. In North ocean regions the global climate change is reflected by changing environmental parameter, such as increasing sea surface temperature, modified water mass stratification and rising freshwater content in the Arctic realm. Within this study the occurrence, abundance and dispersal of toxic algae species is analysed in Nordic seas and the Arctic Ocean, based on molecular detection with a nucleic acid biosensor. Alongside with this it will be assessed whether biosensor systems can serve as an early warning system for human health policies in the field of water resource management.