The Carbon Cycle

Repeat hydrography surveys measure carbon, hydrographic, and other trace elements. The data gathered supports the development of an ocean and global climate forecasting model. The types of studies conducted on I8S will include carbon system studies, heat and freshwater storage and flux studies, deep water mass and ventilation studies (tracer measurement), and calibration of autonomous sensors for developing technologies.

In the next few paragraphs, I’ll cite and summarize part of a statement of purpose written by Jim Swift, the chief scientist and organizer of the first leg of the I8S study. I don’t fully understand all this stuff, of course, but I’ll further clarify the purpose and methods involved in obtaining these data.

The carbon cycle, like the relatively well-known water cycle, describes the exchange of carbon between the atmosphere, oceans, and the biosphere (freshwater systems, living organisms, non-living organic material, and sediments). It’s pretty complicated, I guess, but being able to measure the change in carbon content of the oceans over time tells a lot about the air-sea CO2 flux, helps predict long-term climate change, and furthermore describes man’s influence on the rate of change by comparison with pre-industrial data, and by tracking CO2 measurements in newer versus older (deeper) water.

The carbon system studies on this vessel offer a useful diagnosis of oceanic carbon transport, particularly through interhemispheric carbon exchange to model for large scale effects of global warming on the ocean’s biogeochemistry, whether due to changes in stratification, circulation, or perturbations such as a change in the dust eposition on the ocean’s surface. Additionally, the study will measure partial pressure of CO2 in surface water to assess air-sea CO2 exchange, which is an indicator of changes in the function of the biological pump in surface waters.

One of the major findings of CLIVAR/CO2 is the acidification of the oceans. This is caused by the introduction of carbon dioxide to the ocean; carbon dioxide reacts with water to produce carbonic acid, which is a forward and reverse reaction in equilibrium. But when CO2 is introduced in excess, carbonic acid breaks down into hydrogen ions and bicarbonate, which lowers the pH.

The acidification of the oceans results in all sorts of hell breaking loose, notably including the destruction of the corals. But I personally wonder whether sushi tastes even better as a result? Tangy!