I've seen some other pieces that address one or two of these, but this is the first popular piece to put more of the puzzle together. The End of the Line was really worth seeing on overfishing, but doesn't really touch anything else.
The documentary is also of interest as it introduces the Census of Marine Life, a massive ten year international research project to establish a baseline against which future measurements can be made. More information on the census here, which gives some sense of the size of this project:
"The Census cost $650 million, and involved 2,700 scientists from more than 80 nations and territories working at 670 institutions. They mounted more than 540 expeditions, comprising about 9,000 days at sea, where they studied organisms from the surface all the way down to more than six miles down and in environments that ranged from freezing cold to above the boiling point of water (at the great pressures at the bottom of the sea, water can become superheated near volcanic vents) and ultimately produced about 2,600 scientific papers.
"What was in those papers? Glad you asked: the scientists collectively made 30 million observations of some 120,000 species, found more than 6,000 new ones, tracked the migratory patterns of thousands, and extrapolated from what they saw that the 250,000 known marine species (excluding microbes) are probably only a quarter of what's really out there. If you want to talk microbes, they say, there may be as many as a billion different kinds in the world's oceans."