I just heard about this yesterday, from a marine scientist working on modeling the associated feedback loops as the pace of climate change alters the extent to which giant green zones in the deep ocean are sucking up some of our bulging CO2 inventory. Because of the ‘nature’ of our stupid discourse about climate change, no one hears about this at all. But that doesn’t mean it isn’t, you know, still happening:
Evidence suggests that the past and current ocean uptake of human-derived (anthropogenic) CO2 is primarily a physical response to rising atmospheric CO2 concentrations. Whenever the partial pressure of a gas is increased in the atmosphere over a body of water, the gas will diffuse into that water until the partial pressures across the air-water interface are equilibrated. However, because the global carbon cycle is intimately embedded in the physical climate system there exist several feedback loops between the two systems.
So this is different from hypoxia zones in the Gulf of Mexico, as the shelf there is so shallow that the giant algal blooms just take up all of the oxygen, from everything. At greater depths, the rot has the chance to sink to the bottom and be absorbed by phytoplankton, eventually becoming some form of poop, settling to the bottom and working its way into the system (explanation below). This is why these giant expanses of green water in the open ocean are good things, even as they emanate from the Amazon River and cloud the pristine Caribbean. They are caused by the same forces that create biological dead zones in the Gulf of Mexico – the spewing of nutrient-rich effluent into ocean. But the rate they are changing from other forces, like the changing hydrologic cycle (warning: giant pdf) in the Amazon basin*, must go un- or under-discussed all because of the issue which must not be named, per the above mentioned discourse stupidity, which is more like cupidity than anything.
*The Amazon basin has experienced its worst droughts and its worst flooding in the last five years. Talk about naturally alarming. This is the kind of thing that needs to be reported on with the seriousness given to the pregnancy of a titular princess, mailed out and extensively unpacked, where you are left with the realization that you need to start walking to work now and forever more, saving your car trips for something special-er than buying lottery tickets or browsing at the mall. I have intentionally tried to offer a cursory explanation of the ocean-carbon cycle to demonstrate about how difficult it is to talk, which is one of the lower reasons that we don’t know more about it. No excuse, though it remains.