On the track of marine pollution

This multitemporal radar image shows the huge oil spill caused by the wreckage of the tanker Aegean Sea off the Galician coast.

The ship lost its route because of high winds and bad visibility. It broke off and exploded, spilling more than 70,000 tons of oil into the ocean.

The full extent of the marine pollution - on 13 December 1992 - is shown in dark green. What was still left three weeks later is in lighter colour.

Question : How can remote sensing help in detecting marine pollution ?