Arcana is like energy but follows different rules.
-Arcana can be transformed into energy
-Arcana can be transformed into matter
-Arcana is passive and doesn't influence with the environment by itself
-The environment can influence arcana
While energy can only be used to separate or harvest other energy forms or sometimes separate or fuse matter. Like spending energy to turn food into energy to then turn that energy into thermal energy or when burning wood which separates all the molecules into ashes, coal and smoke. In a sense arcana makes alchemy possible, or at least viable as a concept, maybe it is already possible to turn feces into gold but it might require some really futuristic nuclear technology. However, arcana is not actually alchemy, but something way simpler.
specific quantity of arcana = specific quantity of energy
Some elements affect arcana in various ways, such as duplicating it and increasing the density of arcana in the vicinity of that element, pushing it away, pulling it in, some other elements eliminate the arcana, completely cancelling it out of the universe and this time forever and some elements can make the arcana flow faster or slower or change its the direction. Some compounds of various elements can absorb arcana and fuse with it creating some peculiar situations. Like how some rare varieties of not pure diamonds infused with arcana can transform the non diamond in the vicinity into pure solid hydrogen until the arcana within the diamond is either extracted or consumed then the solid hydrogen starts boiling into vapor. The examples of weird stuff are too many to list.
In this world some organisms produce free arcana as a side effect of their energy system, similar to houw algae produce oxygen.
Other organisms evolved to use the free arcana floating around the world and transform it into usable energy.
Free arcana is like a cloud which can't be seen, can't be smalled and which passes through matter without affecting (most of the time) and I'd imagine the only way to perceive the location of arcana clouds and follow them would be to have some organic device made from specific elements and ''feel'' if there is arcana around on how this element reacts.
So my question would be, can arcana producing and arcana using organisms live on the same planet with plants/algae and animals or would they compete for territory and one eventually drive the other to extinction? maybe not instantly but maybe in a few millenia?