Nick Zarlinga
"If we ignore nature.....maybe it'll go away."
----- Original Message -----
From: "Gerald Pottern" <gbpottern at yahoo.com>
To: "NANFA-List" <nanfa-l-digest at nanfa.org>; <dwalstad at bellsouth.net>
Sent: Thursday, September 08, 2005 5:18 PM
Subject: NANFA-L-- Killer Rain, Stratification, H2S
> Todd & Nick -- Hmmm... well ... no i guess i cant unequivocally say i've
seen an H2S effect. I've seen heavy breathing & erratic swimming sometimes
when i stir up gray clouds and bubbles from dirty gravel, and assumed that
H2S was a cause. One of our recent local club speakers, aquatic gardener
Diana Walstad, said that H2S from anaerobic gravel can be a chronic stressor
on fish and plants, so i figured a sudden pulse oughta be an acute stressor.
BTW - Diana also thinks that having a little iron-rich clay in the gravel
will precipitate the sulfur as iron sulfide and thus protect fish & plants
from H2S damage. Any thoughts on this ???
>
> (Diana -- this NANFA discussion came about from sudden die-offs of pond
fish & algae following heavy summer rains. Theories so far include temp
shock, pH shock, CO2, and de-stratification dynamics).
>
> So, what IS in those sediment clouds & bubbles, and why do i see the
apparent stress reactions when i stir up too much dirty gravel (especially
in shiners) ? I dont think ammonia would accumulate in gravel/sediment -
it's too soluble. Also hard for me to believe that simple physical
irritation from the particulates would cause this. Could something in there
be causing excessive mucus production on the gills and thus suffocating the
fish ??? i sometimes see dirt sticking on their skin, which suggests a
mucus gland reaction. --gerald
>
>
>
> --------- Todd Crail wrote : Hi Gerald, While H2S is definately a caustic
molecule as it acts like cyanide in the bloodstream, binding iron at certain
levels that may seem low (in micrograms per Liter)... My understanding is
that it takes such a concentration of H2S to reach the levels where LD50
tests have shown mortality in fathead minnows due specifically to H2S (like
you would literally begin to barf as it evolved from the tank) that there
would have been far more nefarious conditions in the aquarium (such as NH4+)
before the H2S was in any part, the causative agent.
>
> I can also anecdotally vouch for the presence of H2S in systems having no
observable effect in my systems. With my deep sandbed approach, I am
rotting material continually, to the point where moving rocks sends plumes
of black nasties, and clear bubbles, without any problems. As I mentioned,
I think people are having problems in their tanks because of other issues,
> catch a whiff of something rancid, and assume that was the problem, while
far more volatile and caustic chemicals are running around.
>
> And theoretically, we also have to remember that each night in these
systems, the thermocline would break up, and the system would slowly mix
back together. This would dissipate any H2S trapped in the dissimilar
chemistries as you had mentioned, and avoid a situation where accumulations
could become deadly... Such as the mixing event in Cameroon a few years
back, where a deep, stratified volcanic lake mixed and effectively gased
everything within a certain radius... Much like Dad after Thanksgiving
dinner :) Actually, I shouldn't joke, because it was quite devestating...
But I couldn't resist the analogy. Todd The Madness (tm)
>
>
> ---------- Nick Zarlinga wrote:
> Date: Tue, 6 Sep 2005 20:47:01 -0400
> From: "njz" <njz at clevelandmetroparks.com>
> Subject: Re: NANFA-L-- Killer Rain, Stratification + H2S
>
> Good job Todd!
> As far as Hsulfide, I have never seen an effect on fish. It always amazed
> me since I have smelled some pretty rotten stuff. I do beleive that even
a
> very small concentration is very potent to the olefactory senses. You
have
> definitely seen an effect on fish attributed to this? Nick Zarlinga
>
> -------------
> Date: Tue, 6 Sep 2005 13:03:42 -0700 (PDT)
> From: Gerald Pottern <gbpottern at yahoo.com>
> Subject: NANFA-L-- Killer Rain, Stratification + H2S
>
> Todd/Geoff/Nick/Moon/Mystery & killer rain sleuths - even if the
> hypolimnion (cooler bottom water) of the pond wasnt anaerobic yet, there
> could have been a lot of hydrogen sulfide H2S down in the detritus layer,
> that got churned up by a rain-induced turn-over. You can watch fish
> stress out even in a well aerated aquarium if you stir up deep dirty
> gravel full of aged fish poop (and smell that H2S). Its very toxic stuff,
> but oxidizes or dissipates ??? pretty quick after mixing in aerated
> water. gerald -- hangin on the neuse, NC
>
>
>
>
>
>
>
>
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/ visit http://www.nanfa.org Please make sure all posts to nanfa-l are
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