How do scientists measure turbidity?
Scientists monitor turbidity using a variety of tools. Here are two:
- Transmissometer - a sensitive device that records turbidity values in Nephelometric Turbidity Units (NTUs). The CBIBS buoys use this method to measure the clarity of the water in the Chesapeake Bay. Values over 15 NTUs are typically considered to be detrimental to SAV growth.
- Secchi Disks - a straightforward way of measuring how far light penetrates
into a water column is by using a disk to measure "Secchi Depth". With the sun overhead, a high contrast white-and-black disk (a.k.a. Secchi disk) is lowered into the water until it is no longer visible to the eye. The depth at which the disk disappears is the Secchi depth. High Secchi depth values mean clearer water.
Courtesy of Chesapeake Bay Program
NTU values can range from 0.1 to 100 or more. In general, NTU readings of 15 or higher mean waters have high turbidity and will NOT be able to grow SAV. Check out the graph below to find out if conditions are good for SAV growth at the buoys.
| Real-time CBIBS buoy data | |||
|---|---|---|---|
| Jamestown | Potomac | Patapsco | |
| NTUs | 9.2 | 19.26 | 15.67 |
| Turbidity Level | Med | High | High |
| SAV Growth Conditions | Good | Poor | Poor |
| Return to: Investigate Turbidity |
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