The oceanography lab next to the CTD room is a maze of plumbing linking test tubes, flasks, computer screens
and electronic devices. It's heart, which never stop beating, is the 'debubbleometer', which provides the lifeblood to many of the research projects underway on the voyage.

Surface seawater drawn from beneath the ship is continuously measured by a range of instruments: a salinometer (measuring salt), a fluorometer (measuring fluorescence) a temperature probe and a CO2 monitor. There's a great deal of interest in CO2. People are taking samples to learn more about the relationship between CO2 found in the air and the ocean, which makes the debubbleometer (or air separator) a vital piece of equipment. It's crucial that only the CO2 in the water is measured and not any additional CO2 contained in air bubbles added by turbulence. Before
reaching the C02 monitor the seawater must be debubbled.

The vast Southern Ocean is an important carbon sink for anthropogenic CO2 emissions. (Harvey put the figure of absorption at 17%.) As the greenhouse effect is felt more directly and the planet's forests diminish it is increasingly urgent to understand the role the ocean plays in the carbon cycle.

So how does the ocean draw CO2 from the atmosphere into the water? It's the steady work of phytoplankton photosynthesizing. These organisms consume atmospheric CO2, oceanic nutrients and light and replace it with
oxygen. But the exchange is not consistent. There are also areas of upwelling from the deep where carbon is passed into the atmosphere. And some organisms are more efficient at consuming carbon than others - silica based diatoms, for instance, outpace the carbon-based plankton. But it's even more complex. The plankton in the water not only sucks down CO2 into the water (sinks it) but blows it back (returns it) depending on the time of year and
the place.

Globally it's the microscopic plants in the sea - the pasture of the ocean that do half of the work taking up carbon. The other half is done by plants on land.

The ship is keeping continuous records of CO2 levels in the surface water of the ocean. On board, Steve is looking at the water chemistry of the whole water column. Kristina and Kate are recording this CO2 data. Harvey is most interested in fluorescence and the microscopic critters making up the surface biology. Jill and Andrea are both focusing on the biology but also how it influences the water chemistry. Together they are increasing their understanding of how the cycle is working and the role the Southern Ocean plays as sink for CO2. They are building a picture of the rise and fall of CO2 in the atmosphere and the rise and fall of CO2 in the water. They are documenting where changes are occurring and comparing the sinks, the sources and the changes year to year.

Meanwhile the quiet and steady work of the debubbleometer provides accurate CO2 measurements to them all.



Pic
The debubbleometer
Oceanographic lab