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1. Carbon and carbon-13 in the preindustrial and glacial ocean

   https://doi.org/10.1371/journal.pclm.0000434  

   Schmittner, Andreas; Fillman, Nathaniel J (July 2024, PLOS Climate)

   Carré, Matthieu (Ed.)

   Despite their importance for Earth’s climate and paleoceanography, the cycles of carbon (C) and its isotope¹³C in the ocean are not well understood. Models typically do not decompose C and¹³C storage caused by different physical, biological, and chemical processes, which makes interpreting results difficult. Consequently, basic observed features, such as the decreased carbon isotopic signature (δ¹³C_DIC) of the glacial ocean remain unexplained. Here, we review recent progress in decomposing Dissolved Inorganic Carbon (DIC) into preformed and regenerated components, extend a precise and complete decomposition to δ¹³C_DIC, and apply it to data-constrained model simulations of the Preindustrial (PI) and Last Glacial Maximum (LGM) oceans. Regenerated components, from respired soft-tissue organic matter and dissolved biogenic calcium carbonate, are reduced in the LGM, indicating a decrease in the active part of the biological pump. Preformed components increase carbon storage and decrease δ¹³C_DICby 0.55 ‰ in the LGM. We separate preformed into saturation and disequilibrium components, each of which have biological and physical contributions. Whereas the physical disequilibrium in the PI is negative for both DIC and δ¹³C_DIC, and changes little between climate states, the biological disequilibrium is positive for DIC but negative for δ¹³C_DIC, a pattern that is magnified in the LGM. The biological disequilibrium is the dominant driver of the increase in glacial ocean C and the decrease in δ¹³C_DIC, indicating a reduced sink of biological carbon. Overall, in the LGM, biological processes increase the ocean’s DIC inventory by 355 Pg more than in the PI, reduce its mean δ¹³C_DICby an additional 0.52 ‰, and contribute 60 ppm to the lowering of atmospheric CO₂. Spatial distributions of the δ¹³C_DICcomponents are presented. Commonly used approximations based on apparent oxygen utilization and phosphate are evaluated and shown to have large errors. 

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2. Untangling Carbon-free Energy Attribution and Carbon Intensity Estimation for Carbon-aware Computing

   https://doi.org/10.1145/3632775.3662164  

   Maji, Diptyaroop; Bashir, Noman; Irwin, David; Shenoy, Prashant; Sitaraman, Ramesh K (May 2024, ACM)
3. Insertion of a Transient Tin Nitride into Carbon–Carbon and Boron–Carbon Bonds

   https://doi.org/10.1021/acs.inorgchem.7b02413  

   Wang, Shuai; Tao, Lizhi; Stich, Troy A.; Olmstead, Marilyn M.; Britt, R. David; Power, Philip P. (November 2017, Inorganic Chemistry)
4. Carbon content, carbon fixation yield and dissolved organic carbon release from diverse marine nitrifiers

   https://doi.org/10.1002/lno.12252  

   Bayer, Barbara; McBeain, Kelsey; Carlson, Craig A.; Santoro, Alyson E. (October 2022, Limnology and Oceanography)

   Abstract Nitrifying microorganisms, including ammonia‐oxidizing archaea, ammonia‐oxidizing bacteria, and nitrite‐oxidizing bacteria, are the most abundant chemoautotrophs in the ocean and play an important role in the global carbon cycle by fixing dissolved inorganic carbon (DIC) into biomass. The release of organic compounds by these microbes is not well quantified, but may represent an as‐yet unaccounted source of dissolved organic carbon (DOC) available to marine food webs. Here, we provide measurements of cellular carbon and nitrogen quotas, DIC fixation yields and DOC release of 10 phylogenetically diverse marine nitrifiers. All investigated strains released DOC during growth, representing on average 5–15% of the fixed DIC. Changes in substrate concentration and temperature did not affect the proportion of fixed DIC released as DOC, but release rates varied between closely related species. Our results also indicate previous studies may have underestimated DIC fixation yields of marine nitrite oxidizers due to partial decoupling of nitrite oxidation from CO₂fixation, and due to lower observed yields in artificial compared to natural seawater medium. The results of this study provide critical values for biogeochemical models of the global carbon cycle, and help to further constrain the implications of nitrification‐fueled chemoautotrophy for marine food‐web functioning and the biological sequestration of carbon in the ocean. 

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5. Sunlight Converts Polystyrene to Carbon Dioxide and Dissolved Organic Carbon

   https://doi.org/10.1021/acs.estlett.9b00532  

   Ward, Collin P.; Armstrong, Cassia J.; Walsh, Anna N.; Jackson, Julia H.; Reddy, Christopher M. (October 2019, Environmental Science & Technology Letters)