This has happened several times in earth's history, and caused many extinction events. https://en.wikipedia.org/wiki/Anoxic_event
(Ironically most of our fossil fuel is the result of extinction events caused by the buildup of CO2.)
For an organism to "evolve to survive" a lot of individual organisms have to fail to survive. The evolution of slight-acid-tolerance in plankton will come at the loss of all the slightly-acid-intolerant plankton. That reduces diversity within species, and obviously wipes out entire species that don't have a self-sustainable subpopulation of acid-tolerant individuals from which to rebuild.
If this happens fast then the die-off will be larger. The loss of diversity also makes those populations less robust to other shocks (what if the acid tolerant individuals within a species also tend to really like cold water, and then oceans warm?).
Yes, we could see evolution happen, but one of the ways evolution acts is through mass extinctions.
However acidification is a slow process (compared to rate of plancton reproduction - of course Plankton is a generic term https://en.wikipedia.org/wiki/Plankton and it varies by species)
"Since pre-industrial times, the pH of the oceans has dropped from an average of 8.2 to 8.1 today. Projections of climate change estimate that by the year 2100, this number will drop further, to around 7.8"
Neutral pH is 7, so we can say even the ocean is basic and still will continue to be for some time
Anyone familiar with seawater knows it is not acidic, nor anywhere close. Similarly, inland dry lakes (places like mono, great salt lake, salton etc) are not acidic. But the ph is not relevant to why they can't sustain life. Its a lot more complicated than that.
No, the water in the above examples will not sustain life if you put 'acid' in it to neutralize tested ph. The real core of the issue is the disolved mineral content of the water and how healty or not that is. That ph correlation is neither fundamental nor fully reliable. Its a gross oversimplification.
The fact specific exercise is: not {all acids} introduced into {all alkaline solutions} make for end-state simple (ie, potable) water. The result is often, water with residual mineral content. And often that is, in fact, quite toxic. EG,
Another definition of a basic salt would be a salt that contains amounts of both hydroxide and other anions. White lead is an example. It is basic lead carbonate, or lead carbonate hydroxide. These salts are insoluble and are obtained through precipitation reactions.
oh, life is badass and is doing this all the time. The opposite (nobody evolves to survive) will be very improbable.
In a similar past scenery all known species of Ammonitoidea vanished and dissapear, but some similar cephalopods just lose the external shell, growth a skin over the shell somehow or put the remains of the shell inside the body and its descendants are doing fine as octopus, squids and cuttlefish.
It will be a disaster for the humans that need clams, crustaceans and sea ursins to feed this families, and hundreds of marine species will not survive of course, but for a few species this will be a real blessing.
But I really expect that simple organisms (like, you know, plankton) will evolve to survive
I don't think a small change in ph is as hard for evolution as dealing with the already high amount of salt in oceans
The Zebra mussels are probably going to survive as well