The Effect of Non-linear Internal Waves on the Growth of Antarctic Sponges

Claudio Richter1 and Laura Fillinger1,2, (1)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (2)Terres australes et antarctiques francaises, Saint Pierre, France
Non-linear internal waves (NLIW or solitons) are generated where strong tidal flows interact with bottom topography in stratified waters. Here we report on solitons of exceptional amplitude (>200 m) in the Antarctic peninsula region enhancing diapycnal mixing of nutrients. Production, vertical export and microbial remineralisation of phytoplankton may help sustain vigorous growth of hexactinellid sponges following the collapse of the Larsen A ice shelf. While resuspension of bedload material may help extend favorable growth conditions and aid dispersal of propagules, sponges knocked over in the direction of occasional jets >1m/s testify to the importance of rare events in shaping Antarctic megafaunal communities.