[Aztlan] Phosphorous and the Maya

[Jules Siegel]

I inadvertently deleted the message. Here's something interesting that 
immediately came to mind:

<http://cafecancun.com/eden.shtml>

The ancient Maya may have cultivated mats of algae called periphyton for 
fertilizer, according to new evidence uncovered by scientists at the El 
Eden Ecological Reserve near Cancun.
...

The ponds were covered with thick periphyton mats. Since periphyton were 
found to concentrate nitrogen and phosphorous, El Eden researchers 
theorized that they might have been used as fertilizer. Experiments by 
Sergio Palacios and Ana Luisa Anaya revealed that periphyton is as 
effective as chemical fertilizers.