6 November 2015
El Nino is not just a warming of the surface waters in the East Pacific, the depth of that warm water increases as the thermocline lowers. This keeps nutrient rich colder waters from upwelling to the surface, impacting the very bottom of the food chain. NASA has a cool page (with much more info) where you can toggle back and forth and see the drop in chlorophyll here.
How you can possibly measure microscopic chlorophyll from cold and airless space?? Turns out there is a nice story about that, and you can read it below! (Click the image!)