Total Suspended Matter (TSM) is defined as the concentration of the total suspended matter in water. TSM includes both organic particles (plankton, detritus, etc.) and mineral particles (e.g. clay particles), and is a measure of the water turbidity.
As TSM interferes with the passage of light through the water, it leads to water turbidity, changes in TSM affect a large range of metabolic and biogeochemical processes in marine ecosystems. For example, an increase in turbidity can lead to a decrease in photosynthetic activity and to the depletion of marine vegetation, with repercussions on the marine life
TSM is mainly caused by costal run-off, pollutants and nutriments from land. As a consequence, high levels of TSM are mainly encountered in coastal and estuarine areas. TSM can be considered as a water quality parameter and is a key variable to identify the extent of coastal areas.
It can be directly measured from water samples or estimated from remote sensing of ocean colour.