New additions to the benthic marine flora of Kongsfjorden, western Svalbard, and comparison between 1996/1998 and 2012/2013

We did a survey on macroalgal diversity along a transect off Hansneset (78°39′N, 11°57′E), Kongsfjorden, western Svalbard, between 0- and > 15-m depths in 2012/2013. One major intention was to compare our data to a similar study performed in 1996/1998 at the same site and to document possible changes. We identified 58 species of macroalgae, 12 Chlorophyta, 31 Phaeophyceae, and 15 Rhodophyta. One species (Sphacelorbus nanus) is a new record for Svalbard. Fourteen species are new records for the Kongsfjorden area. Fertile tetrasporophytes of Turnerella pennyi (Cruoria phase) and the microscopic Chlorochytrium stage of Spongomorpha aeruginosa are also recorded for the first time from Svalbard. An increase from 20 to 45 species in the littoral in 2012/2013 compared with 1996/1998 was recorded. This study increases the total macroalgal species diversity of Kongsfjorden to 76. While 62 species were found in 1996/1998 and 58 in 2012/2013, only 42 were common to both investigations. We have made some taxonomic annotations to 20 species/ genera. Strikingly, we did not find again some red algae, such as Hildenbrandia rubra, Palmaria palmata, Polysiphonia spp., or Scagelia pylaisaei, that had been recorded in 1996/1998. Possible reasons for the changes based on recent knowledge from Kongsfjorden are discussed