Local climate warming recorded at maritime Antarctica since 50 years dramatically affects small ice caps such as on King George Island (KGI) at the Northern tip of the Antarctic Peninsula. DGPS measurements revealed surface lowering in elevations up to 270 m above ellipsoid with a maximum of 14 m over 11 years. Glacial area loss at KGI amounted to 20 sqkm between 2000 and 2008. Newly ice free areas opened and succession of diatoms, ostracods and foraminifers can be read in sediments cores. Input of glacial melt water and mineral suspension into coastal areas reach highest monthly yields in January. Timing of the annual discharge wave and volume have increased during the past 5 years. Coastal biota are severely affected by melt water, shading, sedimentation and increased intensity of iceberg scour. 20 years of coastal monitoring indicate that sediment discharge in summer combines with slowly rising water temperatures and freshening in coastal surface waters fronting melting glaciers. Shifts in pelagic communities from larger diatoms to smaller phytoflagellates in the highly stratified summer scenario correlate with large quantities of beaching dead krill. Shifts in the lower distribution limit of macroalgae have cascading effects on grazers and change community structure. Elevated rates of sediment deposition on the seafloor distinctly affect different groups of benthic macrofauna and shifts in benthic community and population age structure can be well explained with species specific sensitivity to sediment and iceberg impact. Most Antarctic macrofauna are highly vulnerable to change, but in some cases we observe unexpected adaptability.
Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 2: Coastal Change > WP 2.3: Coastal Systems under Global and Regional Pressures