Diversitet, taksonomi og utbredelse av marine protister i et Arktis i endring.

Microalgae and protozoa (protists) are the basis for the production of higher trophic levels in the marine food web, and thus for the fisheries. Yet the Arctic protist community contains a vast unknown diversity and many of the described species are poorly known and circumscribed. We lack common references for precise identification of protists in the Pan-Arctic Ocean. This impedes our possibility to detect future changes in biodiversity and distribution, as well as changes in ecosystem structure, dynamics and functioning. In the project we describe the protist diversity and their spatial and temporal distribution in the Arctic Ocean by combining high-resolution microscopy with molecular methods. New cultured strains and single cells isolated from natural samples have been genetically and morphologically characterised. The new DNA reference sequences obtained enable a more precise identification from the large amount of genetic information that has been produced by environmental sequencing and metabarcoding in recent years. We have identified and described species that are poorly known and described several novel species. We provide have further developed tools needed for future surveys and monitoring of marine ecosystems in the Arctic. A web-based Pan-Arctic flora/fauna of marine protists is now under production, as well as improved DNA reference sequence databases for metabarcoding, improved methods to obtain DNA sequences from single cells and improved methods for electron microscopy observations of protists. We have combined molecular and microscopy data to elucidate how the protist community composition is related to environmental factors. This will increase our understanding on how plankton community structure and function may shift due to climate change.

Our work has described novel species of arctic protists, determined the scale of endemism among arctic protists, and provided insight into their biogeography. This will provide a baseline for future studies. We have developed tools for tracking and monitoring state of the Arctic biodiversity. The project has raised the awareness of the importance of Arctic protists, their role in ecosystems and potential ecosystem-wide effects of warming climate in the Arctic. A key resource produced in this project are hundreds of cultures of Arctic protists. Fully characterized using molecular and morphological methods, these represent a unique resource both for future research addressing e.g. the physiology of Arctic protists through experimental approaches. When deposited and made publicly available at Norwegian culture collection of Algae, this collection will represent a highly valuable resource for applied use in different biotechnology fields and vbioprospecting.

The unicelular protists, including microalgae are essential ecosystem-service providers and main suppliers of the photosynthetic products that higher trophic levels of the marine food chain depend upon. Yet the Arctic protist community contains a vast unknown diversity and many of the described species are poorly known and circumscribed. This impedes our possibility to detect future changes in biodiversity and distribution, as well as changes in ecosystem structure, dynamics and functioning. In the proposed project we will describe the protist diversity and their spatial and temporal distribution in the Arctic Ocean by combining high-resolution microscopy with molecular methods. New cultured strains and single cells isolated from natural samples will be genetically and morphologically characterised. The new DNA reference sequences obtained will enable a more precise identification from the large amount of genetic information that has been produced by environmental sequencing and metabarcoding in recent years. We will identify and describe species that are poorly known and insufficiently circumscribed including novel species, and provide tools needed for future monitoring of marine ecosystems in the Arctic. A web-based Pan-Arctic flora/fauna of marine protists will be produced, as well as improved DNA reference sequence databases for metabarcoding. We will combine molecular and microscopy data to elucidate how the protist community composition is related to environmental factors. This will increase our understanding on how plankton community structure and function may shift due to climate change. We will also analyse plankton in historical samples from expeditions by Nansen and Amundsen and compare with present day samples to reveal changes in geographical distribution and community composition over a century in Arctic Oceans.