Abstract Project: AWIPEV_0039

J rgen Laudien (AWI)

Because polar benthic organisms grow comparatively slowly and have few offspring, they are considered particularly vulnerable to a changing climate. With the goal to describe the development of the Arctic West Spitsbergen hard bottom community in Kongsfjorden, Spitsbergen (Svalbard) in response to disturbances, sea-ice or glacier retreat, a long-term succession experiment was initiated in 2002. Settlement plates were installed at a vertical granite wall of the outer fjord Kongsfjordneset; 78 90'N 11 80'E) at a depth of 20m. Additionally, vertical rock walls were cleared of fauna and marked. Plates, cleared substrate and undisturbed communities were photographed annually between 2002 and 2012 to assess the resilience of benthic communities after disturbance due to sea-ice and glacier retreat. In 2024, the plates and hardbottom test plots will be resampled to assess the changes after another decade (2022 was not possible due to the pandemic). Due to climate change, Svalbard is currently experiencing a de-crease in sea ice causing a shift in kelp communities (Bartsch et al. 2016). To evaluate possible changes in the epifauna below the kelp belt during 2001-2024, a quantitative dive study from 2001 (Sahade et al. 2004) will be repeated at three sites (Prins Heinrich ya, Hansneset, and Kongsfjordneset) along a depth gradient (15-20-25-30m). This study will reveal consequences of Arctic warming, serve as a model for a typical future scenario for changes along other Arctic coasts, and serve as a basis to develop spatio-temporal scenarios of changing polar biodiversity.