![Chaz](/data/avatars/m/0/103.jpg?1640368481)
Chaz
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- Sep 13, 2006
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And there are run-off events like some streams will experience this year due to the amount of snow on the ground and rain on top of that snow. Pushes the ph down to fatal levels.
Cooler=wetter, warmer=drierpcray1231 wrote:
The Little Ice Age is an interesting topic, and the same discussion could shed light on the long term effects of the current warming.
Generally speaking cooler = drier and warmer = wetter, streams. The ones that really aren't in danger of getting too warm in our summers.
k-bob wrote:
tb: "So, how does the hemlock/hardwood hypothesis deal with these known impacts from acid precipitation, with all these miles of streams with no brook trout whatever, or very low pops, and very little invertebrate life? ... According to your theory, what was the situation with these streams pre-settlement? Did they have brook trout then? Was the pH higher or lower than now? Were inverts higher or lower than now?"
my ideas are about invertebrates not acid rain. acid rain is a tangent I already addressed. I have not suggested that there were massively different acidity levels in the distant past -- for any reasons.
for ex., as I wrote above (emphasis added): "2) A stream that shifts from hemlock- to hardwood- drained forest would see changes in multiple variables. Yes, a small reduction in water acidity based on things I have read, in one case of paired study of hemlock and hardwood draining streams, the one under hardwood had a pH .25 higher. The pH difference was attributed to fewer acidic hemlock needles. Hemlocks were harvested because of tannic acid, right they produce acid. However, the pH level only has to be appropriate for trout, they don't calculate some balance w/ acid rain or anything else."
so pH is a tangent to the basic point about invertebrates ..
Cooler=wetter, warmer=drier
Maybe not all of you have been on some these acid rain impacted streams. You turn over the rocks and there are scarcely any bugs at all.
You cannot separate the two things out. Either one effect is greater, or the other one is, and the result is that the pH is either higher or lower in the past.
I say the effect of acid precip is MUCH greater, and completely overwhelms any countervailing effect from the hemlock/hardwood thing.
pcray1231 wrote:
TB, think of it this way. Most streams were originally slightly acidic, just like our rain is naturally slightly acidic. Agreed?
Now, we agree that man, via acidifying the rain beyond what nature intended, has, as a general rule of thumb, made BOTH the rain and the streams more acidic. Great.
Yet, we can dump a bunch of limestone sand in a stream, and negate that, even turn it slightly basic. Definitely a higher pH than nature intended. And we can watch as brookie populations improve as a result. We've done it.
Now, that's intentional, but still a man-made improvement of waterways, no? You're gonna say that never, in the white man's history, has he unintentionally done a single thing with a positive effect on a single stream?
You are arguing against a position that has not been taken, by me or anyone else.
pcray1231 wrote:
Cooler=wetter, warmer=drier
Overall, wrong. Higher temp = more evaporation from the oceans = more rain. That's the general consensus, looking at it on a global basis.
How that pertains to PA specifically, and how it varies by season, well, I dunno, and not sure that anyone really does.
pcray1231 wrote:
TB, think of it this way. Most streams were originally slightly acidic, just like our rain is naturally slightly acidic. Agreed?
Now, we agree that man, via acidifying the rain beyond what nature intended, has, as a general rule of thumb, made BOTH the rain and the streams more acidic. Great.
Yet, we can dump a bunch of limestone sand in a stream, and negate that, even turn it slightly basic. Definitely a higher pH than nature intended. And we can watch as brookie populations improve as a result. We've done it.
Now, that's intentional, but still a man-made improvement of waterways, no? You're gonna say that never, in the white man's history, has he unintentionally done a single thing with a positive effect on a single stream?
k-bob wrote:
I see a steep little ravine brookie stream in reports with pH professionally tested at 6-6.5 in various points, good macros in the professional assessment, very good brookie fishing, and a hardwood canopy. just sayin,...
to be clear, my view is that the hardwood tree leaf litter could affect the invertebrate numbers, and thus the biomass of trout that eat the invertebrates. I am not suggesting that the hardwood canopy does much to change the pH... back in the day there may well have been hemlocks over the stream, whose leaf litter may have resulted in lower invertebrate density, and possibly, lower trout biomass.
pcray1231 wrote:
You are arguing against a position that has not been taken, by me or anyone else.
Then we both are. I'm agreeing that the overwhelming majority of PA streams have lower brook trout populations now than they did pre-European settlement. The reasons are variable and definitely include acid rain, which is devastating on some streams, bad on all, and overwhelms positive changes on most.
Just not every single one now has a lower population. There likely is a small number that have increased the population in that time frame.
How small a number? I dunno. Greater than zero.
Do you agree with that?