The simple usefulness of the Secchi disk

Like the humble measuring tape around a tree at chest level, sometimes the simple tools are the best. They're timeless.

Often, having a higher quantity of cheap, mediocre data is better than a tiny handful of ultra precise measurements.

It's awesome going from the software world, counting double precision numbers, to field biology where you'd just lay ropes out in random places and count pine cones by hand, hoping you didn't miss too many.

It's funny, I always had this image of NASA and NOAA supercomputers doing detailed climate modeling (and sure, those exist too) but don't underestimate the power of just having hordes of boots on the ground (or in a boat) taking simple measurements.

"...“Higher turbidity levels,” according to the EPA, “are often associated with higher levels of disease-causing microorganisms such as viruses, parasites and some bacteria.” "

In other words, the clearer water is often a sign of higher microorganism contamination? Quite surprising.

Didn't realize the device was named after someone, we were told it was an acronym and the name morphed a bit to sound like a "sucky" disk.

Edit: an idea — instead of “can you still see it?”, ask “can you prove you can still see it?”.

If the disk had an arrow then statistically you could measure how many times you fail to correctly see the direction in which the arrow is pointing.

As the disk gets deeper you’ll see the failure rate increase and maybe there is either a clear spike in failures or, more likely, a point where the error rate is above 50% / guessing for that particular field scientist’s eyesight. Maybe you could even calibrate eyesight so that results from different teams match up?