What isn't mentioned here is the fact that crashes in ocean biodynamics always precede and then coincide with mass extinctions on land. That is mainly due to the loss of
plankton and
algae life, ergo, oxygen.
Ocean warming and acidification also deplete ocean oxygen. Also, this study seems not to cite evidence on (all possible) causes for warming and so should refrain from making recommendations on the use of fossil fuels. While fossil fuel use is probably the main cause of warming, calling for their reduction in a study which does not address this area scientifically is unprofessional, and encourages further resentment and closemindedness from those readers who may not yet agree that fossil fules cause warming. Not the way to change or influence minds. Preaching to the choir.
Without Action On Climate, Another Mass Extinction Event Will Likely Happen In the World's Oceans For more on mass extinction events, see my tags here and in my own LJ.