Environmental context Soil carbon sequestration plays an important role in achieving the goal of carbon neutrality. We studied the characteristics of organic carbon distribution and sequestration by stable carbon isotopes in nine types of soils in China and found that macro-aggregates possessed more organic carbon with a low degree of decomposition, while the overall direction of organic carbon transfer between aggregates was from macro-aggregates through micro-aggregates to the grain-size fractions of chalky clay. These results provide a foundation for understanding soil carbon sequestration in China’s cultivated lands.

Environmental context Organophosphorus (OP) is bioavailable to phytoplankton with photolysis can play an important role in the process. The photolysis behaviour of an OP (adenosine 5′-monophosphate, AMP) in seawater was investigated, and AMP can release inorganic phosphate under environmentally relevant light conditions, indicating OP photodegradation might be important in the phosphorus biogeochemical cycle. The results are helpful to further understand the bioavailability and cycle of OP in marine environment.

Environmental context. Arsenic (As) contamination in agricultural soil threatens safe agricultural production. Therefore, an ex situ magnet-assisted soil washing, using different types of nanoscale zerovalent iron was tested as a remediation option in soil restoration. Uncoated nanoparticles was the best tested option, with As removal at 45.5% and the nanoparticles were reusable up to four times.