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Re: Muddy thoughts

eworobe at cc_UManitoba.CA wrote:
> There are burrowing animals in aquatic muds. Perhaps one of the best
> known are chironomids which can be in concentrations of tens of thousands
> per square meter.

Earthworms are the primary soil building agent for topsoil. They
literally have to eat their way through the ground in order to create
their burrows and they bring the mineral remains mixed with the organic
detritus which they eat back to the surface which we call earthworm
castings and which forms the topsoil. It is very fertile.

> In a lake, everything comes to the substrate so the fertility of the
> substrate mimics the fertility of the overlying water. Taking sediment
> cores, you can date them and tell exactly when certain events occurred
> due to nutrient spikes at given depths.


> Nutrient concentrations are thousands of times higher in sediments than
> in overlying waters. This is true for both micro and macro nutrients.

How would this compare to the topsoil which is eroding to form the
sediment? Would the fertility be roughly the same? I think
denitrification is faster under water. The reason I ask is because
somebody might like to know the relative fertility of some soil types
which he might have available. I was thinking that we could establish a
baseline test for measuring soil samples for nitrate and phosphate.
Something like take so many grams of the soil and soak it in a given
volume of water and measure the nutrient concentrations after a week or
so, perhaps less... The initial test should perform several extractions
to see when the largest peak of N release occurs but so long as the test
is always performed in a consistent manner, we should get a good
baseline for comparison. I guess where that would need a longer term
test is if the sample has significant organic material which has to
undergo decomposition before its nutrients become released. The peak of
that sort of decomposition occurs at about 3 weeks from other info I got
from Diana Walstad. Have you done soil or aquatic soil fertility

Does decomposition proceed at a higher rate on land than under water? I
think anaerobic decomposition is slower isn't it?

Thanks for your remarks Dave.

Steve Pushak                              Vancouver, BC, CANADA 

Visit "Steve's Aquatic Page"      http://home.infinet.net/teban/
 for LOTS of pics, tips and links for aquatic gardening!!!