New life at the end of the world: Seaweed and invertebrate colonization of the Arctic intertidal

Warming temperatures and a reduction of sea-ice scour opens the Arctic intertidal as habitat for colonization by both seaweeds and marine invertebrates. Indeed, large increases in the biomass of seaweeds and invertebrates on Arctic coasts have already been documented in the past decades and are predicted to continue. To understand the ramifications of this widespread ecological change in the Arctic intertidal, we needs to examine species-specific responses and how these drive inter-species interactions and ecosystem dynamics.

In this project, I will examine the stability of components of the Arctic intertidal ecosystem along an environmental gradient (low wave & sea-ice stress -> high wave & sea-ice stress). Specific objectives are to study the effects of abiotic forcing on i) seaweed morphology ii) the colonization of the intertidal by seaweeds and invertebrates iii) the genetic constitution of intertidal seaweed and invertebrate populations.

During a field expedition to Svalbard in June 2024, Haakon Hop and I performed quadrat frame and transect surveys of intertidal biota at six sites in Kongsfjorden. We collected seaweed and macrofauna samples, along with eDNA and water samples. These samples will form the basis of further morphological, taxonomical, and genetic analyses.

We expect that this project will provide basic information about the genetic and taxonomic diversity and biomass of species in the Arctic intertidal along an environmental gradient. Furthermore, results about seaweed morphology and inter-species interactions will help us better understand the resilience and function of different ecosystem components, which is crucial for predicting Arctic ecosystem adaptability in the face of drastic environmental change.

Have the gear at Hansneset and ready to sample! Photo by Haakon Hop.