re: Misc

To: Aquatic plants list <aquatic-plants at actwin_com>
Subject: re: Misc
From: Cynthia Powers <cyn at metronet_com>
Date: Wed, 27 Nov 1996 13:36:42 -0600 (CST)
---------- Forwarded message ----------
Date: Wed, 27 Nov 1996 14:21:37 -0500 (EST)
From: DIONIGI MALADORNO <MALADORD%A1%RNISD0 at mr_nut.roche.com>
Subject: SAEs source - E. horemanni follow-up - algae/cyanobacteria thought
To: AQUATIC PLANTS <Aquatic-Plants at ActWin_com>

If anyone is interested, yesterday I saw approx. 20 young 1.5" SAEs (at
least labeled as such: no flying fox -type bright stripe on the back,
lateral dark band extending into the tail fin) for sale at 4-5$ each at:
Aqua-Tropics, 1080 US Hwy 46 (west-bound lane just before the merging with
Rt. 3), Clifton, NJ phone (201) 365-0200. Actually, they called them
"siamese flying fox". I have no private interest in the store!

My E. horemanni are still flowering. After the first one sent out a flower
stalk more than a six weeks ago, also the second one did the same. Quite
interestingly, at that time the CO2 reactor had not been working for a
while, suggesting that it may not be too critical in my tank's conditions.
Two weeks ago the original plant sent out another stalk. They are all still
flowering. The plants are trying to keep them out of the water. Only the tip
of the original stalk has recently produced a single plantlet. I did not
expect this process top go on for this long!

Just one thought for comments from the algae gurus, and anyone else of
course: wouldn't it be more correct to think at the algae growth limiting
effects of low nutrient levels 
in a more dynamic fashion than what frequently written? In other words, I
wonder if the complete growth limiting effect of a given nutrient present at
very low levels  (say phosphates for example) may become inadequate when
light levels increase. I noticed in three of my basically algae-free tanks
that very limited amounts of cyanobacteria and beard algae are growing only
on the floating plants and at the tip of the taller plants that reach the
surface. I wonder if the higher light levels available towards the surface
provide some extra energy necessary for algae to better compete with plants
for the low nutrient levels present in the tank. In such situation, a small
amount of algae still coexists with actively growing plants. Away from the
surface the lower light conditions (still quite good in absolute terms) can
be utilized only by plants, since algae are not efficient enough to capture
the low-level nutrients.  I am not trying to advocate to use lower light
levels (on the contrary,...); I am rather trying to  think the concept of
competition between plants and algae as a dynamic process with different
levels of equilibrium, where the relationship between growth, nutrients and
light is not always linear.  Does it make sense?   


Dionigi