[APD] Potamogeton % composition

[Thomas Barr <tcbiii at earthlink_net>]

http://www.npwrc.usgs.gov/resource/literatr/pondweed/table3.htm

Also, decay rates for S. pectinatus: 2% per day with 158 day for total losses.
Virtually all the K+ was lost and 60% of the P was lost in the first 7 days.
Total times for some species were as little as 2.3 days and up to 435 days for cattails and other emergents.

This species also removed P from the water column, but the reserve of P is generally much less in the water vs the sediment. So when the water column is limiting, the plants will use the sediment P. Most of the P in the water column is tied up as plant biomass, this was not tested/accounted for when lake samples were taken in the past.
Even with rapid decomposition of P from decaying plant matter, little, if any P is detected in lakes indicating rapid recycling(uptake) from the water column. In warm aerobic waters, there is an almost complete breakdown of macrophyte biomass and very little sedimenting out as particulate matter(mulm).

Even with our packed tanks full of weeds and at high growth rates etc, we have low rates of mulm accreation.    
Regards, 
Tom Barr
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