Wikipedia says it's both nitrogen and phosphorus. https://en.wikipedia.org/wiki/Carnivorous_plant https://en.wikipedia.org/wiki/Carnivorous_plant > It can be f

Wikipedia says it's both nitrogen and phosphorus. https://en.wikipedia.org/wiki/Carnivorous_plant https://en.wikipedia.org/wiki/Carnivorous_plant > It can be fixated only through biological means I don't think this is very correct, but why do these biological means fail in bogs/swamps? Kinda my point: Other plants and ecosystems figured out the nitrogen problem all over the world. It's more or less the same everywhere, since nitrogen naturally comes from the atmosphere. AFAIK, there are more or less three ways to have nitrogen input into an ecosystem: Lightning, biological fixation in plants/microbes and artificial synthesis/fertilization. I suspect the swamp ecosystem has something going which makes nitrogen fixation difficult. All other plants in the swamp need nitrogen to grow, too, how are they doing? Maybe it is the (often) low pH, maybe it's a lack of trace metals for certain enzymes. Maybe the anaerobic conditions favor inaccessible conversion of nitrogen in decay. Nitrogen can't be completely exhausted, because you have (low) constant influx from the atmosphere everywhere on Earth's surface, even without biological fixation. Phosphorus, on the other hand, can be effectively depleted. The "cycling" of phosphorus happens on geological timescales. A low soil pH may leech out the phosphorus from minerals and have it carried away by wind and water. I still don't think plants would go the carnivorous route just for the nitrogen. If anything, I suspect they recycle the "nitrogen" as amino acids to save on synthesis. Some carnivorous plants apparently secrete phosphatase into their prey. That's a lot of evolutionary effort...