While concern over global warming from the rising levels of greenhouse gases in the atmosphere as a direct result of the burning of fossil fuels is now widely recognized, the other side of the carbon dioxide emissions equation – ocean acidification via CO2 enrichment - has received far less attention. Anthropogenic CO2 only resides in the atmosphere temporarily. While some small fraction of the anthropogenic CO2 takes a brief detour through the terrestrial biosphere for about 40 years (on average) before being released back into the atmosphere by decay, about one-third of the CO2 emitted each year is quickly absorbed by the oceans. In the long run some 85% of all of mankind's CO2 emissions will be absorbed by gas exchange across the air-sea interface. This amount is established by the chemical capacity of the ocean and the total amount of fossil fuels burned. The annual rate of uptake is controlled by ocean mixing. There is no ambiguity here. The accumulation of fossil fuel CO2 in the upper ocean, and its penetration to the deep-sea in newly formed bottom waters, is plainly observable by ocean chemists. We have now “disposed” of about 530 billion tons of fossil fuel CO2 in the oceans, and the rate of invasion now exceeds 1 million tons of CO2 per hour. We are thereby acidifying the ocean and fundamentally changing the remarkably delicate geochemical balance. The consequences for life in the sea are only now beginning to be investigated, but comparable events in our geologic history have caused massive changes in ocean ecosystems, including widespread extinctions.
Artist's rendition of anthropogenic CO2 and the resulting ocean acidification
In the past year we have explored the needs of the national and international community in regards to studying this problem so that the necessary and useful systems can be created and tested at MBARI. On March 20, 2007 we held a workshop co-sponsored by the Center for Ocean Solutions, with senior staff in attendance from the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA), to lay the foundations. From these efforts a clear picture has emerged. There is great interest in MBARI creating a usable and exportable form of the Free Ocean CO2 Enrichment (FOCE) techniques with colleagues from France, the U.K., Norway, Canada, Taiwan, and Japan, who have all expressed direct interest. Key NOAA staff have also expressed strong interest and are exploring ways to work with us.
We are re-designing the prototype system developed in 2005 to reflect the lessons learned, and using short-term connections to the MARS cable to enable long-term testing deployments, thereby addressing other elements. Recent work in Japan has established that biological impactsfor example impaired reproduction in shrimpoccur at lower pCO2 levels, and over longer time scales, than previously recognized. The MBARI experiments in 2008 and beyond will have an increased emphasis on early life forms of key species. The economic impacts of this phenomenon will be additive to the thermal impacts of climate change, and will be expressed in complex waysfor example in fisheries, and in tourism as coral reef systems are affected. More broadly we are happy if this theme draws more widespread collegial interest and engagement (both within MBARI and beyond) as the subject matter unfolds.Edward Peltzer.