The International Weddell Sea Oceanographic Expeditions or IWSOE are a series of scientific research expeditions to the Weddell Sea begun in 1967, involving cooperation among Norway, Canada, Chile and the United States. IWSOE research projects have involved a variety of institutions and covered a wide range of disciplines. Other subjects of IWSOE research include the Weddell Sea currents and the biology of krill, a species of zooplankton abundant in the area.