The identification of carbon pools and the quantification of carbon stocks is necessary to (1) track changes in ecosystem dynamics, (2) inform science-based ecosystem and blue-carbon management, and (3) evaluate ecosystem and food web models. However, estimates of organic carbon stocks in marine ecosystems are incomplete or inconsistent. Therefore, we provide a first consistent estimate of relevant organic carbon stocks of a distinct marine ecosystem- the Baltic Sea. We estimate its contemporary standing stocks of 18 non-living and living organic carbon pools using data from literature and open-access databases. In contrast to existing data, our estimates are valid for the entire Baltic Sea, include necessary pools and are verifiable, as we describe data sources, methods and the associated uncertainties in detail to allow reproduction and critical evaluation. The total organic carbon (TOC) in the Baltic Sea ecosystem amounts to 1,050 ± 90 gC/m2 (440 ± 40 Mt). The non-living stocks account for about 98.8% and the living stocks for 1.2% of the TOC. Our estimates indicate that benthos has the highest living organic carbon stock and that the stock of particulate organic carbon (POC) has been underestimated in some previous studies. In addition, we find a partially inverted biomass distribution with a higher stock of primary consumers than primary producers. Our estimates provide a baseline of the size and distribution of the organic carbon in the Baltic Sea for the current period. Analyses of inorganic carbon stocks and the interplay between inorganic and organic stocks must follow to further define the baseline of total carbon stocks in the Baltic Sea.

Offshore wind farms (OWFs) can increase the transfer and stock of organic carbon (OC) in the surrounding sediments during their operational phase, while their construction and decommissioning release carbon. To answer the question whether sediments of OWFs trap more OC than they release, we estimate the net carbon effect over the entire life cycle (construction, operational and decommissioning phases) of OWFs in the Southern North Sea. Based on existing studies we compare the increased OC flux due to the colonization of organisms at the foundations of wind turbines and the OC loss due to sediment-disturbing activities during construction and decommissioning. Our results show that the areal intensity of carbon release in the disturbed areas is about 43.5 times higher than that of carbon trapping in the entire area of the OWFs. However, since the disturbed areas only account for about 0.50 ± 0.06% of the total area of the OWFs, in absolute terms about 4.6 ± 1.4 times more carbon is trapped in the sediment of the OWFs than is released. Due to limited data availability and the resulting need for extensive assumptions, our estimates only represent orders of magnitude. We therefore provide sensitivity estimates that define the limits of our calculations in terms of disturbance depth, remineralisation ratio, scour protection measures and heterogenous OC contents. In addition, we identify shortcomings of our extrapolation. Further research, especially more advanced impact assessments of construction and decommissioning processes must follow to improve the understanding of impacts of OWFs on sedimentary OC.

The ability to conduct interdisciplinary research is crucial to address complex real-world problems that require the collaboration of different scientific fields, with global warming being a case in point. To produce integrated climate-related knowledge, climate researchers should be trained early on to work across boundaries and gain an understanding of diverse disciplinary perspectives. This article argues for social breaching as a methodology to introduce students with a natural science background to the social sciences in the context of integrated climate sciences. The breach of a social norm presented here was to ask people whether the experimenter could ride on an elevator alone. We conclude that the approach is effective in letting students with a natural science background explore and experience the power of social reality, and is especially suitable for a small-sized introductory class.

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The ability to conduct interdisciplinary research is crucial to address complex real-world problems that require the collaboration of different scientific fields, with global warming being a case in point. To produce integrated climate-related knowledge, climate researchers should be trained early on to work across boundaries and gain an understanding of diverse disciplinary perspectives. This article argues for social breaching as a methodology to introduce students with a natural science background to the social sciences in the context of integrated climate sciences. The breach of a social norm presented here was to ask people whether the experimenter could ride on an elevator alone. We conclude that the approach is effective in letting students with a natural science background explore and experience the power of social reality, and is especially suitable for a small-sized introductory class.