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Old 03-08-2021, 11:30 PM   #11
montcalm
Mobster
 
Join Date: Mar 2014
Posts: 1,677
Quote:
Originally Posted by Wldrns View Post
I believe it is due to the natural condition of the soils in the region being acid to begin with, plus the tannin and decomposing leaf litter adds to the acid. So there is no natural ability to obtain neutral pH water in the first place. Interestingly, just a few miles west on the other side of the Black River valley, there are vast limestone deposits that would neutralize any acid. Accumulated winter snows melt and release an entire season of acid contained in the precipitation all at once, just at the critical wrong time when trout are spawning and most susceptible to reproductive failure from acid water. Soils in the eastern Adirondacks are less acid, plus most of the acid precipitation from Ohio smoke stacks and other polluters has already been deposited to on the western Adirondacks. I am sure you can find scientific studies published on the process, especially regarding acid rain in this region. I've read some in the past, but memory on specifics is perishable.

The answer is in the ALSC report... somewhat.

The type of lake impacted is definitely as I was seeing in the data - they are mostly what they call mounded seepage lakes. The lakes get most of their input from direct deposition on the lake surface and have no outlet. Layers of muck and organic matter tend to seal them off a bit. These lakes/ponds must lose water through the ground and evaporation. I'm not sure if the acids cannot move through the groundwater, but the acidification doesn't seem to be an issue for what they call flow-through seepage lakes, which don't have a lot of muck and organic matter. Perhaps the peat traps enough of the acidic water to keep increasing the pH?

There's also a fair deal of chemistry that I don't understand, and I don't think was well understood in the report either. Yes, there are a number of natural processes that make certain lakes acidic, and they have low neutralizing capabilities but it doesn't really answer why the depositions become trapped and increase the pH to a lethal level - if that is even the case. It seems like they didn't really know how well those type of ponds could support fish. Also whether or not a total freeze of the pond (because its small and shallow) could be responsible for killing the fish population.

The lakes that were probably the most disturbing to people were the "thin-till drainage lakes" that were becoming sterilized. A very small amount of the lakes that were acidic were this type. And some still had fish at the time of the survey.
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