These plankton blooms happen naturally and are part of the biosphere already. There's a whole food chain that the guy breaks down in the podcast. He was saying

These plankton blooms happen naturally and are part of the biosphere already. There's a whole food chain that the guy breaks down in the podcast. He was saying that this is usually kicked off by whale poop I think but because of the low numbers of whales, it happens way less now.