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- CO2 concentrations go up and down over the seasons on short, annual time frames, (Earth "breathing in and out") but overall, the concentraton of CO2 has steadily risen over the last several decades
- get CO2 plus an indication of past temperatures, going back ~800,000 years
- CO2 mainly at 2 ppm until recently ("recently" being 450,000 years)
- temperature curve roughly matches CO2 concentration curve
- 15,000 to 20,000 years ago we had an ice age
- humans have affected the system as well, and we know this based on actual data plus physical-chemical-biological models of the Earth system
- global temps projected to go up 2-4 degrees, global CO2 concentration projected to go up 400 ppm over next 100 years
- What is a gigaton? A billion tons of CO2!
- Even w/discussions among governments around the world and with scientists, we are not doing very well here. Actual emissions higher than worst IPCC projected scenarios!
- PgC = gigaton
- 10e15 g, 38,000 gigatons of CO2 in ocean
- the oceans do a great deal to absorb CO2
- but we are still concerned about the atmospheric sliver of the pie
- Ocean scientists go to sea 40-50 days at a time and collect thousands of water samples, from the seafloor up through the water column to the sea surface. We can measure the carbon (C) and oxygen (O) in the water samples
- WOCE = World Ocean Circulation Experiment
This is a map of the station locations from the global survey of carbon measurements as part of WOCE, the World Ocean Circulation Experiment. The red stations indicate measurements collected as part of the US WOCE one time survey. The yellow stations were a part of NOAA’s OACES program. We have also made an effort to incorporate as much international data as possible. The blue stations in the Indian Ocean are from the French. Pacific data came from the Australians, Japanese, and Canadians. Much of the new Atlantic work was performed by the Europeans. The synthesis began in the Indian Ocean. These cruises had the best coordination are required the least effort to synthesize. We have just completed the Pacific synthesis and are now moving on to the Atlantic. All together we hope to have something on the order of 100,000 unique sample locations with at least two measured carbon parameters.
- gives us historic baseline from which to move forward
- human-caused CO2 reaches deep into the ocean
- oceans take up CO2 out of the atmosphere. Can the oceans keep that up in order to save us?
- Chemistry of the ocean is indeed changing
- 22 million tons of CO2 per DAY goes into the ocean!
- Note the chemical equation:
CO2 + H2O <--> Carbonic Acid <--> Bicarbonate ion + H ion <-->Carbonate ion + H ion
- carbonic acid part is where notion of "ocean acidification" comes from
- carbonate ion can go into bicarbonate or shells. If it decreases then less is available for CaCO3 needed by animals to make their shells or coral reefs
- Projections are for CO2 in ocean to go UP, carbonate ion to go DOWN, pH to go DOWN
- organisms that need CaCO3 won't be able to get enough and they will start to dissolve (no protective shells)
- YES, from pCO2 (concentration of CO2) and pH measurements in water samples from places such as Station Aloha
- CaCO3 (or aragonite) goes into the shells
- What will changes in ocean chemistry do to organisms and ecosystems?
- More CO2 means less carbonate ion in ocean, more dissolving of shells, disappearance of shell-bearing species
- Warm colors = aragonite or CaCO3 is in solution for animals to use
- 1765 = healthy ocean, but now we are at marginal levle
- By year 2100 we will be in real trouble
- There is no debate about this in the scientific community
- Pictures show shells dissolving
- in nature the time frames are much longer
- can organisms adapt to changes in environmenta? Will more genetically diverse critter develop and help save the biodiversity of the oceans
- We shall see, but we now that acidity will increase in short term, temps will too.
- high CO2, drop in # of species, lack of corals
- Oregon data show how low pH water is exposed very near shore
- CO2 numbers are very high nearshore
- this affects sea urchins, barnacles in nature (e.g., tide pools), also commercial oyster hatcheries
- with too low a pH critters cannot calcify (make shells)
- the oceans help by absorbing literally tons of CO2 - thank goodness for the oceans
- we (humans) have changed the pH of the oceans by 0.1 and we are heading for a whopping 0.3
- our emissions on land WILL change the ocean
- we still need to know more so scientific studies continue in earnest!
- check out the special issue of Oceanography to go more in depth!
http://dusk.geo.orst.edu/oceans/ocean_acid.html