There are examples at a smaller scale. Nutrient pollution (nitrogen, phosphorous fertilizer in water) can build up for quite a while in a lake with no apparent

There are examples at a smaller scale. Nutrient pollution (nitrogen, phosphorous fertilizer in water) can build up for quite a while in a lake with no apparent effect. For reasons not well understood, sometimes after quite a long time (many years) of rising nitrogen/phosphorous levels, run-away growth of algae occurs suddenly and rapidly, depleting the lake of oxygen and killing off most animals and plants. Lakes and ocean regions which have undergone this process thoroughly become stable in their own way, with anaerobic bacteria and algae, but no plants or fish: https://en.wikipedia.org/wiki/Dead_zone_(ecology) https://en.wikipedia.org/wiki/Dead_zone_(ecology)