A survey for macroalgal fresh biomass was performed in the high, mid and low intertidal zone at five sites along the fjord axis of Porsangerfjorden in July 2022. This dataset is part of a space-for-time comparison between low-Arctic Porsangerfjorden and high-Arctic Kongsfjorden. The aim was to document differences in macroalgal biomass and community composition between two Arctic fjord systems at different stages of cryosphere loss to understand how benthic vegetation in the high-Arctic will likely develop in the future.

The data contains a fresh biomass data for a range of macroalgal taxa in the intertidal. Macroalgae were identified to the lowest taxonomic level possible. The taxonomic 'Class' of the taxon is provided to indicate to which type of canopy-forming Fucales or which macroalgal lineage the understory intertidal taxon belongs to. Within the taxon column there is a 'Fucus vesiculosus spiralis distichus', a 'Acrosiphonia Spongomorpha' and a 'Dictiosiphon Chordaria Stictyosiphon' value. Because these are field data, and the distinction between these species requires genetic lab work, the exact species identification is not possible.