Setting Sail to Study Ocean Carbon

There’s a mixture of relief and joy every time a robotic float is recovered. Years of research and months of intense engineering go into preparing each device for its life at sea, no matter how brief the stint. So when Carbon Flux Explorer 3 sent its ping this afternoon to say that it had surfaced and completed its mission, a day after it was first dropped into the Santa Cruz Basin, the reaction was one of excitement and anticipation.

Even with the GPS signal, it’s an impressive feat to find and retrieve the float. It is a small target in a large ocean, and the two antennae are black. The people who first saw the robotic float were instructed not to blink. Read More »

The ocean’s biological carbon pump occurs at very fast time scales, so it has been difficult to study the various environmental dynamics influencing its processes. Determining whether the carbon pump is strengthening or weakening – and why – would require ongoing monitoring that is impractical to do for humans on a ship.

That is where robotic technology comes in. Berkeley biogeochemist Jim Bishop invented the optical sedimentation recorder (OSR), an instrument designed to catch organic matter sinking vertically and funnel it to a glass platform. A camera below the platform takes images at regular intervals, and those images can determine the nature of the matter that settles on the glass stage.

The OSRs typically hang down from surface buoys, but research has indicated that such tethering makes them susceptible to a sideways pull that affects the quantity of particles collected. Read More »

At 2:27 p.m. today, the first Carbon Flux Explorer was deployed, and if all goes well, we will see it again in about 24 hours. Its entry into the water did not come with the cheers I had expected. I was told that this was because many of the researchers had done this before, and there was still a great deal of work to do after the launch. (I still clapped.)

While the float was on the boat, the researchers programmed in a 30-minute delay in activation so that it wouldn’t start sinking right after deployment. What followed after the Carbon Flux Explorer (CFE) was dropped into the water was a meditative half hour of watching the float bobbing along the water’s surface to make sure it sinks as scheduled. Read More »

It’s not a great thing when the CTD (Conductivity, Temperature and Depth) Rosette bumps into the hull of the ship, as it did on one of the launches today.

The CTD weighs about half a ton when the water sample canisters are empty, and about 1,300 pounds when the bottles are full. A wayward swing could not only damage the sensitive – and expensive – equipment, it could cause serious injury and death.

But the CTD has an outer cage meant to protect the equipment, and it did its job very well. No harm, no foul. Read More »

As I started writing this, an array of sensors was taking measurements from the surface to near the bottom of the Santa Cruz Basin. They are being tested with a CTD (Conductivity, Temperature and Depth) Rosette device, which will help researchers characterize the distribution of biomass at different water depths.

CTD Rosette probes provide scientists with data about water temperature and salinity in real-time through an electrical cable attached to the ship. The CTD includes gray canisters that allow scientists to collect water samples at various depths. Read More »