[YeGoblynQueenne]

The article reports that 90% of plankton is gone, not "the plankton are gone". Additionally, it seems that this is a correction of an earlier estimate according to which 50% of the plankton should be gone by now:

>> The landmark research blames chemical pollution from plastics, farm fertilisers and pharmaceuticals in the water. Previously, it was thought the amount of plankton had halved since the 1940s, but the evidence gathered by the Scots suggest 90% has now vanished.

Even if this correction is an overestimate, and the old estimate was right, the quantities of plankton halving since 1940 is still a disturbingly high amount of reduction. As to seeing plankton from space that doesn't really say anything unless we know what proportion of the plankton that exists is visible from space. For instance, it might not be possible to estimate total plankton quantities just from looking at a picture with a particular "bloom" concentrated in an area.

I'm surprised about these numbers also but I don't know how I could easily trash the research reported, just because I've seen pictures of plankton. I think that's just making an overgeneralisation.