Hi,
Definitely interesting and a lil surprising as Anubias are slow growing plants unlike Java fern. Can we think that the experiment was only influenced by the Java fern, or say 90% ?
I have no idea. I did the experiment with both Java Fern and Anubias thus experiment doesn't tell us anything on possible uptake individually. It's possible I suppose.
But I've done some scientific paper reading on the subject in the meantime and there are some interesting things I've read:
for example:
-Plants mainly use 2 survival strategies.
1. Fast growing and trying to out-compete by gobbling up easily available resources. In the process they forsake photosynthesis, quality of their structure and ignore harder to process resources.
Meaning they will take forms of nitrogen that's easy for them to uptake. Their structure will be mostly made of water and empty space with very little Nitrogen, sugars, proteins, etc. Their leaves, body and roots will root, melt, dry, die easily if easily available resources aren't there anymore. Dried matter contains very little incorporated nitrogen, sugars, proteins, etc.
Therefore: if you have fast growing substrate or water column plants and you feed them with easily available resources (plant fertilizers which are mostly Nitrogen in easy to absorb form) they will grow fast and mostly ignore Nitrogen in water column (Ammonia, Nitrites, Nitrates and iron, phosphorus, etc from tank waste; because they have those in more easily absorbed forms from fertilizers).
2- Slow growing plant strategy.
They will absorb any resources available to them. Putting great effort into photosynthesis, 'quality' structure that is closely packed with nitrogen, sugars, proteins, etc. Have hard skin, body, leaves that can survive periods of lack of resources, have great water retention, etc. In the process they forsake trying to out-compete by growing fast (they won't try to outgrow other plants to be highest and have access to sun on top, but will concentrate on maximizing sun/resources they have available to them).
Their dry matter structure has much much greater concentration of Nitrogen, sugars, proteins then the structure of fast growing plants.
When one resource becomes unavailable they will use their stored reserves in structure to replace structure that takes up ammonia (for example) and redesign their structure to uptake nitrates if available. Same with leaves depending on availability of light or not, etc.
- generally; fast growing plants take up more Nitrogen than slow growing plants. But it greatly depends on temperature, environment, etc. At some temperatures slow growing plants take up more nitrogen than fast growing plants, etc.
So that was scientific paper on agriculture plants and grasses (Vegetables, trees, hay grass, etc) I assume it holds true for aquatic plants like slow growing Anubias and fast growing plants.
My conclusion from it:
If you have Slow growing tough structure plants and fast growing weak structure plants in aquarium without fertilizers = fast growers will use more Nitrogen produced by fish. But not as much as visual observation would suggest. Maybe 2x more max as per scientific research on different plants.
-Add fertilizers and that changes completely. Anubias might be the ones taking wast majority of resources that aren't fertilizer
