1. The ocean is a big place. Its important to understand the ocean’s saltiness or ‘salinity’ (S) and temperature (T). T&S shapes the ocean’s physics, chemistry, & biology. The ocean is not uniform so T&S can be different depending on where you are on the map & how deep look.

2. But how do scientists study T&S in the ocean? They use an instrument called a conductivity-temperature-depth sensor (CTD). These sensors have a thermometer, an electrode that is sensitive to changes in salinity, & a pressure sensor that lets you know how deep down it is

3. A great explainer on a CTD works and how scientists use them can be found here: https://oceanexplorer.noaa.gov/technology/ctd/ctd.html

Today we say, thanks to CTDs for helping us better understand the ocean!

Happy #CTDAppreciationDay!

4. CTDs are often deployed by scientists on ships but are also drifting around on autonomous underwater robots called ARGO floats and ocean gliders - how cool!

More about ARGOs here: https://imos.org.au/facilities/argofloats
More about gliders here: https://imos.org.au/facilities/oceangliders

@IMOS_AUS @teuta

5. One last thing... scientists often deploy CTDs with empty bottles that catch water for us to study. We also send down other sensors alongside CTDs

Below is a CTD paired with optical sensors that tell us how light interacts with in seawater.

#scicomm #CTDAppreciationDay!