The colour of the sea depends on its composition and the way the components of seawater absorb and/or scatter light. For example, the colour of the ocean is affected by sediments in suspension (sand, mud, clay), phytoplankton, dissolved organic matter from plant decomposition, etc. This research project is based on this relationship… but it moves in the opposite direction. The objective is to develop methods to convert satellite measurements into maps of chlorophyll (an indicator of phytoplankton) and suspended sediments.

Why look at the sea's colour ?

Nitrates and phosphates from human activity (such as the agricultural use of fertilisers) reach the sea via the rivers. These biological nutrients can significantly modify the coastal ecosystem and cause a proliferation of undesirable species of phytoplankton (microscopic marine plants). Scientists call this phenomenon “eutrophication”. According to international agreements such as the Oslo and Paris Conventions, now OSPAR Convention, or the prevention of marine pollution, the states responsible for eutrophication problems must take measures to reduce such pollution, for example by limiting the use of fertilisers and constructing waste water treatment plants. There is also an international obligation to monitor the evolution of this problem.