The new debate [Are floating plants technically semi-aquatic?]

[OliveFish05]

I would consider them aquatic, personally...

 

[itiwhetu]

True aquatic plants will take their nutrients through their leaves, and therefore they will die if they are not completely submerged. Example Ambulia or Cabomba

 

[StevenF]

lilies, red root flowters anacaris, anubias,and duck weed are all classified as flowering plants. Duck weed flowers are very very small and almost invisible. Anacharis and Anubis rarely flowers.

Geologic evidence (fossils) indicates the first flower plant appeared about 140 million years ago. Alll flowing plant are decedents from that one plant. So they were not originally aquatic but some overtime adapted to aquatic environments.Some like Anubis are semiaquatic while other have adapted so well that they can only live in an aquatic environment.

Almost all plants in this hobby are dependents of terrestrial plants.

 

[GaryE]

I used to keep Rivulus killifish, from South America. They like to leave the water and lounge around on leaves, or hang from silicone above the water line. So are they non aquatic fish

I've been building tanks with semi-aquatic zones for years. Part of the tank will have maybe one cm of water, and marsh/bog plants growing on (in) it. Some of the fish I enjoy breeding use those spaces for eggs, and they are great fry refuges. They're stream edges.

So is there a distinct, sharp like between water and air? I think it's blurry, and there is life evolved to exploit that transition zone.

That's fine, so long as everyone realizes the issue/differences. BTW, floating plants are certainly more needful of being aquatic than being terrestrial, because of the leaf structure (which is aquatic--the amphibious plants usually if not always have different structured leaves for submersed and emersed growth), and their uptake of nutrients. Aquatic plants use ammonium as their source of nitrogen, and only turn to nitrate when forced to because it means extra work (= energy lost) changing nitrate back into ammonium in order to use it, whereas all terrestrial plants take up nitrate as their source of nitrogen, and so far as I am aware all do this via their roots. Aquatic plants assimilate their nitrogen via the leaves in most cases.

Byron's got the answer - it's in the structure of the plants (and fish, and crustaceans, and...). I have rooted aquatic plants that grow up out of water, which makes them semi-aquatic and semi-air but 100% bog. So many creatures we keep come from rainy dry season habitats, where what underwater one week is dry the next. You have to look beyond what your eyes can see with a good question like that.