Water turbidity (i.e. transparency) is a measure of the amount of suspended solids in the water. The higher amount of suspended solids, the "murkier" and more turbid the water is. Turbidity is caused by things such as algal growth, phytoplankton, sediment resuspension, and run-off. Turbidity influences the amount of light that can reach the benthic region (bottom) of the mesocosm. In highly turbid waters, less light reaches submerged macrophytes and algae, thereby limiting photosynthesis and having knock-on effects on species reliant on those primary producers. Additionally, large amounts of suspended particles can decrease the amount of oxygen in the water via increased heat absorbance of the particulates (warm water holds less oxygen than cold water). In these mesocosms, turbidity is measured via a Secchi disk, which measures the "Secchi depth".