What is this thing - SD 1080?

[Mr Link]

Apparently fisheries research for the US Geological Service. Here is an online article about past missions. https://www.saildrone.com/news/usgs-adv ... e-superior

Some university-lead research centers have also been using autonomous diving gliders, that sail around various lakes and collect temperature and water properties at various depths.

[Guest]

What is the "SD 1080 - uncrewed" that has been bobbing around Lake Superior for the past couple of months? From the picture on Marinetraffic.com it looks like a giant fishing bobber with a sail. I'm assuming it's some sort of research instrument - but researching what?