Where do you get kelp from?

I'm curious to know, where exactly do kelp come from? Is it harvested from certain regions of the ocean? Or do they grow naturally in specific habitats? Are there specific conditions required for kelp to thrive? I'm also interested in the process of harvesting kelp, does it involve specialized techniques or equipment? Additionally, how does the origin of kelp impact its quality and nutritional value? It would be great if you could provide some insights into these questions.