I have an admittedly massive bias toward terrestrial systems (rangelands specifically, if we're being honest). I just taught succession (cliffs notes: succession the change in community composition of an ecosystem over time, e.g. how plant communities develop from forbs and annual grasses to forests as soils develop, given the right climate conditions, etc.). And up front I was like, listen, the early work on succession was done with plants, because the guys doing it were plant people, and plus, plants don't move, and plus, I like plants, SO, this is primarily going to be a plant focused conversation. But then after, the lead instructor was like — hey, you should tell them about whale fall to illustrate that succession does happen in non-green plant situations.
Whale fall is when a dead whale falls to the bottom of the ocean and causes a massive energy boost in the system, and there is a predictable pattern of organism assemblages that play out as the whale decomposes. It is so cool. Watch this video!