When I tell people I do underwater surveys, they almost always have an image of glorious tropical seas, great visibility, and general oohing and ahhing at the beautiful marine critters. The reality is somewhat different (especially when you're not in tropical waters!).
A few years ago, a small team of intrepid divers went to an offshore reef just off the coast of Jersey (Channel Islands) to survey maerl. Maerl is a hard red seaweed, that forms little hard blobs which lay on the sea floor. It's a super important habitat for our smaller ocean brethren. It's also super slow growing - which means if they are pulled up or destroyed by things like bottom trawling or dredging, they don't come back anytime soon.
Maerl Beds in the Fal and Helford SAC (England). Credit Natural England/Ross Bullimore (CC BY-NC-ND 2.0)
On this particular survey, my job was to conduct a general habitat and species survey of the site and keep hold of the SMB - basically, an inflatable sausage attached to the end of the line you can see me holding that sits on the surface of the sea, so we can be spotted by our boat - and other people in the area.
Not only was the visibility not great, but there was a current that was trying to take me in one direction whilst the wind was pulling the SMB in the other!