Ocean Optics:
Observing ocean biogeochemistry with optics

Why Measure TSM?

Total Suspended Material (TSM; aka total suspended solids, suspended particulate matter) can include a wide variety of material such as silt, decaying plant and animal matter, and industrial waste. TSM is often used to examine water column turbidity and water quality. As the amount of suspended material increases, the appearance of the water becomes cloudier as more light is scattered by particles within the water column.

Changes in TSM concentration can have long ranging effects on the biogeochemistry of an area. As TSM levels increase, light penetration decreases adversely affecting photosynthesis by primary producers. Suspended solids can clog fish gills, either killing them or reducing their growth rate.

TSM as a Biogeochemical Proxy

TSM measurements are labor intensive and require discrete sample collection. The relationship between TSM concentration and light attenuation or scattering can be exploited and optical parameters might be used as a proxy for TSM.

Protocols for Measuring TSM