Aerobic degradation of organic carbon inferred from dinoflagellate cyst decomposition in Southern Ocean sediments

• Published in: Quaternary Research
• Main Authors: Kupinska, Monika, Sachs, Oliver, Sauter, Eberhard J., Zonneveld, Karin A.F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2012
• Subjects: Southern Ocean
• Online Access: http://dx.doi.org/10.1016/j.yqres.2012.04.001; http://api.elsevier.com/content/article/PII:S0033589412000464?httpAccept=text/xml; http://api.elsevier.com/content/article/PII:S0033589412000464?httpAccept=text/plain; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400008450

Abstract Organic carbon (OC) burial is an important process influencing atmospheric CO 2 concentration and global climate change; therefore it is essential to obtain information on the factors determining its preservation. The Southern Ocean (SO) is believed to play an important role in sequestering CO 2 from the atmosphere via burial of OC. Here we investigate the degradation of organic-walled dinoflagellate cysts (dinocysts) in two short cores from the SO to obtain information on the factors influencing OC preservation. On the basis of the calculated degradation index kt , we conclude that both cores are affected by species-selective aerobic degradation of dinocysts. Further, we calculate a degradation constant k using oxygen exposure time derived from the ages of our cores. The constant k displays a strong relationship with pore-water O 2 , suggesting that decomposition of OC is dependent on both the bottom- and pore-water O 2 concentrations.