CARBON MICROCYCLE (Cµc)
Duration: 2 years (October 2019 until September 2021)
Around half of all carbon dioxide (CO2) produced by humans since the Industrial Revolution has dissolved into the ocean. Therefore, understanding how the ocean exchanges CO2 with the atmosphere is critical for the prediction of climate change. The global assessment of the air–sea CO2 exchange is based on atmospheric and oceanic measurements. For the latter, ship data are generally collected at an approximate water depth of 3–5 m, e.g., the inlet depth of ship-based pipelines or the CTD depth closest to the water surface. The rationale behind this is the assumption that no gas gradient exists in the upper 0–5 m of the surface layer . However, ignoring this surface layer, including the sea surface microlayer (SML) directly at the air–water interface, can cause biases of 20–50% in estimating the exchange rate of CO2.The primary objective of Carbon microcycle project, which is funded by the German Research Foundation (DFG) to measure this CO2 gradients in the top 2 meters of the ocean. Our earlier studies showed that pH in the sea surface microlayer differs from the underlying water.