New carbonate system proxies: foram culturing and pteropod potentials

Global climate change is one of the most pressing challenges our society is facing currently. Climate sensitivity due to atmospheric CO2 doubling will most likely increase global temperatures by 2.0 – 4.5 °C (IPCC 2007). While some direct effects of increasing CO2 are straightforward (e.g. ocean acidification, atmospheric temperature rise), the mid- and long-term impacts of increasing CO2 levels are less easily predicted due to poorly qualified contribution from various potential positive and negative feedbacks in the climate system. Palaeoreconstructions combining temperature reconstructions and atmospheric paleo-CO2 levels are necessary to validate models that aim at predicting future global temperature increases. Reconstructions of atmospheric CO2 from ice-cores are confined to the last 800 ka (Lüthi et al. 2008), while reconstruction of atmospheric pCO2 on longer timescales rely largely on marine sedimentary archives (e.g. Hönisch et al. 2012). Within the latter, foraminifera play a central role, since the chemical and isotopic composition of their shells reflect the physicochemical properties of the seawater that these organisms grew in (Emiliani 1955). Palaeo atmospheric CO2 concentrations can be estimated from past seawater CO2 (aq), which in turn can be reconstructed when two out of six parameters are known of the oceans carbonate system (“C-system”; CO2,HCO3–, CO32–, pH, DIC [dissolved inorganic carbon] and total alkalinity). (…)

Keul N., Langer G., de Nooijer L., Nehrke G., Reichart G.-J., Bijma J. & Schneider R., 2015. New carbonate system proxies: foram culturing and pteropod potentials. Nova Acta Leopoldina NF 121, 408:305 –309. Article.


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