|Monitoring ocean acidification from space. Animation 2 of 2 of a sequence showing ocean acidification and how it can be measured by Earth observation satellites. As carbon dioxide builds up in the atmosphere, increasing amounts of carbon are entering the world's oceans, changing the chemical balance of seawater, leading to ocean acidification. Marine chemistry can now be studied from space. Ocean salinity and temperature can be detected from space by their effect on electromagnetic emissions from the ocean surface. Salinity alters emissions at microwave wavelengths, recorded by the European Space Agency's SMOS (Soil Moisture and Ocean Salinity) satellite; temperature controls emissions at infrared wavelengths, recorded by the ATSR (Along Track Scanning Radiometer) instrument. These measurements can be combined with nitrate concentration measured from ships to estimate the amount of dissolved inorganic carbon in the ocean. This new work will help identify regions at risk from sudden short-term acidification events, which can damage marine life, including sensitive tropical reefs, wild fisheries and coastal aquaculture. For the series of two clips, see K008/6629 and K008/6627. For the entire animation with and without captions, see K008/6544 and K008/6540.