I'd like to talk about how a surely useful tool, like sodium fluorescein, may be abused in the caving community, even by academicals.
(Not looking to exclude any caver, in short dye tracing is using a water-soluble dye poured into flowing water so that it can be used to detect and analyze connections among water flows, since it can be measured downstream even at extremely low concentrations not visible to the naked eye).
I assume that you've read about some amazing discoveries of stygobic fauna living into phreatic water and likely excluded from the outer world and any obvious outside connection since millions of years.
Well, given that luckily or unluckily (depending on one's point of view) we still know very little about groundwater fauna (and even have a hard time just to imagine how beings can live there into ways so different than us and most of the things we've seen and studied for centuries), with most species observed only once, sometimes as single specimens or known only from empty shells and considering that fluorescein isn't that toxic but also not exactly harmless (more data on this can be spilled later, even if AFAIK there is nothing that conclusive about invertebrates toxicity), is it really that important to potentially sacrifice unknown living beings with unknown distribution and population number, just to dye a load of cubic meters of water upstream to see if they're dyed downstream?
Or is it just important in say 5% of the times it's used? Or even then, it is justified and necessary only because it's easier to refuse the idea that it may harm the unseen (as opposed to the seen) and even then, it's just silly primitive non-taxpaying bugs?
Are we being over-enthusiastic into using it just because one can personally buy a bucket-worth of dye with his/her own wallet and head out of the store with still some cash left, or would it be the same if we used more expensive tracers?
IMHO and relatively short experience, some researchers either think only about their own field, for example geology, and forget about everything else or improvise as such just because they can rig, like most of us, a bucket full of florescein, some dye traps and a fluorometer, hoping this will leave a mark into our community, while said mark unfortunately can't be assured to be left only into that conjectural space.
If there's any willingness to discuss about this, I'd also like to see what's your opinion about short-lived (2-6 days) radioactive isotopes tracing and the pro/cons set it brings along (just as about any tracing I guess) or choosing not to trace at all.
Thank you