Historical abundance and distributions of Salpa thompsoni hot spots in the Southern Ocean, with projections for further ocean warming

A bstract Over the last three decades, a significant variability in Salpa thompsoni occurrence has been observed as a response to the environmental fluctuations of the Southern Ocean ecosystem, e.g. changes in sea surface temperature as well as shrinking of ice-cover extent around the cold Antarctic waters. This study presents the historical data of salps abundance from the southwest Atlantic Sector of the Southern Ocean and covers time span of 20 years. Presented dataset allowed to track previous fluctuations in Antarctic salp abundance and enabled to combine their distribution with different bottom depth, thermal and ice conditions. The subsequent goal of this work was to reveal hot spots of salps location and to predict the future range of S. thompsoni distribution with upcoming climate warming in the next 50 years. Results of our study revealed that the highest salp number was located mostly in the shallow shelf waters with ice-cover and lower temperature. In the studied area, Salpa thompsoni hot spot distributions have been located mostly around Elephant Island but also within islands around Brensfield and Gerlache Straits, as well as to the south near the cold Bellingshausen Sea. The inference of future salp distribution demonstrated that the range of S. thompsoni would presumably move southwards enlarging their habitat area by nearly 500 000 km 2 .