Mellon, S., Kienast, M., Algar, C., Menocal, P. de, Kienast, S.S., Marchitto, T.M., Moros, M., & Thomas, H. (2019): Foraminifera trace anthropogenic CO2 in the NW Atlantic by 1950. Geophysical Research Letters, 46, doi:10.1029/2019GL084965
Plain Language Summary:
Since the industrial revolution, the burning of fossil fuels for human energy and transportation needs has caused an accumulation of carbon dioxide (CO2) in the atmosphere. Over the same time period, nearly 30% of CO2 emissions have been taken up by the ocean. This absorption is not uniform; therefore, understanding local CO2 uptake rates is essential for assessing future ocean acidification risk. Our study investigates and presents the first long‐term history of carbon for the Northwest Atlantic shelf region. The CO2 emitted from fossil fuel burning has a distinct carbon isotope ratio compared to the preindustrial background level. Organisms called foraminifera incorporate the carbon isotope ratio of ocean carbon into their shells, which eventually sink to the seafloor where they are preserved in the sediments. For our analysis, we collected five sediment cores containing foraminifera from the NW Atlantic, resulting in carbon isotope records that span the last 4,000 years. We find evidence of fossil fuel‐derived CO2 in the NW Atlantic starting in 1950 and translate carbon isotope trends into estimates of fossil fuel CO2 uptake rates by the surface ocean. Results from our study can be used to assess and predict future ocean acidification risk.