Fossil-fuel carbon fingerprint reaches the deep North Atlantic
The use of fossil fuels alters both the concentration and the carbon isotope composition of carbon dioxide in the atmosphere. Since surface water exchanges carbon dioxide with the atmosphere, this also alters the isotopic composition of the carbon dissolved in the ocean. In a new study, a team from MARUM—Center for Marine Environmental Sciences at the University of Bremen has now determined how…
Fossil-fuel combustion has introduced a detectable carbon isotope signal, known as the Suess effect, throughout the deep North Atlantic Ocean. Researchers from MARUM—Center for Marine Environmental Sciences at the University of Bremen analyzed water samples collected during expeditions in 2017 and 2018, along with measurements of the human-produced gas sulfur hexafluoride (SF₆), to quantify this anthropogenic impact.
They discovered that the Suess effect is now present in nearly all North Atlantic water masses, with young subsurface water masses exhibiting the strongest signal. This effect is particularly pronounced in the Labrador Sea, where eddies transport the signature to depths of up to 2,000 meters. The presence of the Suess effect in deep, ancient water masses, such as the Northeast Atlantic Deep Water, suggests that it has not been in contact with the atmosphere for several hundred years.
The study, published in Geophysical Research Letters, highlights the increasing detectability of industrial activities in the ocean and its preservation in marine fossils, marking the beginning of the Anthropocene in long-term geological records.
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