Re: CO2 and aquatic plants

>From: Elizabeth Worobel <eworobe at cc_UManitoba.CA>
>Date: Fri, 1 Mar 1996 15:00:47 -0600 (CST)
>Subject: Re: CO2 and aquatic plants
>Hey Steve, not to get too picky, but there are very few aquatic plants 
>which obtain CO2 from the sediment. These are Isoetes spp., Littorella 
>uniflora, Lobelia dortmanna, Eriocaulon spp. Generally, this ability is 
>restricted to small rosette plants growing in extremely oligotrophic 
>waters. Other species, such as Valisneria spp., Heteranthera dubia 
>and Myriophyllum spp. have been tested and found not to have the ability 
>to extract CO2 from the sediment (Hydrobiologia 98:3 - 7, 1983).

Not to get too picky, but how do you know that the above plants are THE only
plants?  Have all tropical species been tested, including Echinodorus,
Cryptocoryne, etc?  Also, can't the sediment (or the substrates used in
aquaria) be a source of CO2?

Dr. Frank :-)

Neil Frank                 Aquatic Gardeners Association,  Raleigh NC