Y'all are just gonna have to put up with me being proud of my 11 yr
old daughter.
This past year we did a lot of canoeing on various clear rivers here
in N. FL and a few dark Tannin stained ones. Most of the clear rivers
are infested with the invasive non-native hydrilla and she hated
paddling through it. She notices that the dark tannin stained rivers
are mostly clear of it. One day she asked, "Dad, does the tannin stop
the hydrilla from growing". Her older (20 yr old) biology major
sister told her "It is probably that the Hydrilla cannot get enough
sunlight in the Tannin stained water". So, we looked it up and found
that Hydrilla grows well in most dark water. Hmm, Science Fair
Project. So, I went to the Wacissa River and got some Hydrilla. We
ordered some Tannic Acid and filled 7 gallon jugs with river water.
One had dark food coloring in it, one had nothing but river water and
the rest had varying amounts of Tannic Acid. WE put Hydrilla in
each.I truly expected nothing to happen. Two days later, DRAMATIC
differences. The higher concentrations of Tannic Acid had the
hydrilla looking bleached and brown. The one with food coloring
looked good, just like the control with just water.. After 5 days,
the hydrilla in the higher concentrations had sunk to the bottom and
looked bad.
So, she may be on to something. However, now that she has done her
experiment and written it up, I suddenly find that possession of
hydrilla is illegal. We are going to report anyway and hope for the
best. We did kill all the hydrilla afterwards.