Yuxin Zhou Homepage

        Carbon has several isotopes. Carbon 12 is the most common one. There's also the heavier carbon 13. Plants prefer the lighter carbon 12. Fossil fuels such as oil and coal come from ancient plant. As we burn fossil fuels, we send less carbon 13 and more carbon 12 to the atmosphere. The decrease of the ratio between carbon 13 to carbon 12 in the atmosphere is called Suess Effect.

        The recent decrease in d13C in the deep sea due to uptake of carbon has been measured in samples taken on hydrographic surveys, although these surveys only provide snapshots of deep sea d13C. The long-term decrease in d13C has been estimated using modern hydrographic properties, but there are no direct measurements.

        My project focused on records of d13C from benthic and planktonic foraminifera, collected south of Iceland in the North Atlantic Ocean. The cores have high accumulation rates and, based on radiocarbon, modern core tops. We find a monotonic decreasing trend since 1850 that is significant in two out of the three benthic records we have generated. A tracer simulation, with Transit Time Distribution and Equilibrium Time Distribution generated from previous tracer modeling studies, predicts a trend that is similar to our observations at the core sites. The presence of the Suess Effect in some of the cores is consistent with previous estimates on the uptake of anthropogenic CO2 in the newly formed North Atlantic Deep Water.

Rubino et al., 2013
Rubino et al., 2013. The atmospheric d13C Suess Effect.
Olsen and Ninnemann, 2010
Olsen and Ninnemann, 2010. The recent decrease in d13C in the deep sea due to uptake of carbon has been measured in samples taken on hydrographic surveys like this one. However, these surveys only provide snapshots of deep sea d13C and a long-term record is missing.

Project News

In February, I presented this project at the 2016 AGU Ocean Sciences
Meeting, New Orleans, Louisiana.