July 2nd, 2010

woods, Elizabeth, camera, April

Gulf Ecology and the Oil Spill: ramifications

The implications of the Deepwater Horizon blowout are obvious in some ways (oiled pelicans, dead turtles, air pollution from burning oil)  and less so in others.  To discuss this in any depth, it's necessary to give some background on what's going on with marine ecosystems in a time of rapid change in atmospheric carbon dioxide (CO2) and the  pH of ocean water (it's becoming more acidic) and rising sealevel. 

Let's start with the basics of the carbon/oxygen biogeochemical cycle.   The source of oxygen in our atmosphere is photosynthesis--plants using the sun to break CO2 apart and release oxygen molecules, O2 (should be a subscript, but...)    Simplistically, plants release oxygen and fix carbon into their tissues--carbon is a component of sugars, starches, fats, and proteins.  Animals (like us) take in oxygen and combine it with sugars, starches, fats, and proteins to release energy to do everything we do (grow, repair, move, reproduce, etc.)   We exhale CO2.   In fact, many plants also use oxygen and exhale some CO2, but they release more oxygen than COs...and that's where we get it.    Much, if not most, of the oxygen currently being produced is released by photosynthetic plants in the ocean, including tiny one-celled phytoplankton, kelp beds, and the like--there's a lot of ocean surface, but these plants can only photosynthesize in the upper waters, where enough sunlight penetrates.  When the system is balanced, the oxygen levels in the atmosphere stay about the same (where we like it--about 21%) and the CO2 levels stay about the same (where plants like it and it's not toxic for any of us and the oysters' shells don't dissolve--about 0.03% of the atmosphere.) 

Collapse )