Trace elements and isotopes (TEIs) are important to marine life and are essential tools for studying ocean processes1. Two different frameworks have arisen regarding marine TEI cycling: reversible scavenging favours water-column control on TEI distributions2–5, and seafloor boundary exchange emphasizes sedimentary imprints on water-column biogeochemistry6,7. These two views lead to disparate interpretations of TEI behaviours8–10. Here we use rare earth elements and neodymium isotopes as exemplar tracers of particle scavenging11 and boundary exchange6,7,12. We integrate these data with models of particle cycling and sediment diagenesis to propose a general framework for marine TEI cycling. We show that, for elements with greater affinity for manganese oxide than biogenic particles, scavenging is a net sink throughout the water column, contrary to a common assumption for reversible scavenging3,13. In this case, a benthic flux supports increasing elemental concentrations with water depth. This sedimentary source consists of two components: one recycled from elements scavenged by water-column particles, and another newly introduced to the water column through marine silicate weathering inside sediment8,14,15. Abyssal oxic diagenesis drives this benthic source, and exerts a strong influence on water-column biogeochemistry through seafloor geometry and bottom-intensified turbulent mixing16,17. Our findings affirm the role of authigenic minerals, often overshadowed by biogenic particles, in water-column cycling18, and suggest that the abyssal seafloor, often regarded as inactive, is a focus of biogeochemical transformation19,20.
Current antibiotic-resistant bacteria (ARB) disinfection techniques commonly rely on large dosages of oxidants, resulting in the presence of considerable amounts of residuals and toxic disinfection byproducts (DBPs) in water. Herein, we propose a highly effective ARB disinfection approach via activating an ultralow concentration (10 μM) of chlorite (ClO2–) by naturally abundant sunlight to generate various reactive species (i.e., HO•, Cl•, ClO•, and ClO2) with negligible generation of halogenated DBPs. Combining in situ characterization with theoretical calculations, we reveal that, in addition to the photolysis of ClO2– in the bulk solution, ClO2– ions electrostatically adsorbed on the positive local sites of lipids can boost light absorption and facilitate the in situ generation of reactive species upon sunlight irradiation, enabling more efficient attacks toward cell membranes and the intracellular antioxidant enzyme system. The intracellular antibiotic resistance genes (ARGs) are then released and further degraded, inhibiting horizontal ARG transfer. This approach can also achieve excellent ARB disinfection performance in real water matrices (e.g., lake and river water) in 1 L tanks and 500 mL plastic bottles with natural sunlight irradiation. Overall, this work presents an efficient, safe, and sustainable method to inactivate ARB with deep insights into disinfection mechanisms at the subcellular level.
In this paper, we develop a new adaptive hyperbolic-cross-space mapped Jacobi (AHMJ) method for solving multidimensional spatiotemporal integrodifferential equations in unbounded domains. By devising adaptive techniques for sparse mapped Jacobi spectral expansions defined in a hyperbolic cross space, our proposed AHMJ method can efficiently solve various spatiotemporal integrodifferential equations such as the anomalous diffusion model with reduced numbers of basis functions. Our analysis of the AHMJ method gives a uniform upper error bound for solving a class of spatiotemporal integrodifferential equations, leading to effective error control.
