No, but we're working on it... Seriously, if 90% of plankton had been killed off there would be some very noticeable effects. Something like 50% of our oxygen

No, but we're working on it... Seriously, if 90% of plankton had been killed off there would be some very noticeable effects. Something like 50% of our oxygen is generated by phytoplankton. (50% is probably the floor - I see some estimates going up to around 70%) And plankton of all types is at the bottom of the food chain - if 90% disappeared there would be mass starvation in our oceans.