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.
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.
You can see that the visibility wasn't that great, but what you can't see is the current that was trying to take me one direction, whilst the wind was pulling the SMB the other. This is why I'm kneeling on the seabed (away from the maerl in case you are wondering) so I could make some notes on the board I am holding, whilst also making sure I don't let go of the SMB!