Anthropogenic nutrient enrichment has caused phosphorus (P) accumulation in many freshwater sediments, raising concerns that internal loading from legacy P may delay the recovery of aquatic ecosystems suffering from eutrophication. Benthic recycling of P strongly depends on the redox regime within surficial sediment. In many shallow environments, redox conditions tend to be highly dynamic as a result of, among others, bioturbation by macrofauna, root activity, sediment resuspension and seasonal variations in bottom-water oxygen (O₂) concentrations. To gain insight into the mobility and biogeochemistry of P under fluctuating redox conditions, a suspension of sediment from a hypereutrophic freshwater marsh was exposed to alternating 7-day periods of purging with air and nitrogen gas (N₂), for a total duration of 74 days, in a bioreactor system. We present comprehensive data time series of bulk aqueous- and solid-phase chemistry, solid-phase phosphorus speciation and hydrolytic enzyme activities demonstrating the mass balanced redistribution of P in sediment during redox cycling. Aqueous phosphate concentrations remained low ( ∼ 2.5 µM) under oxic conditions due to sorption to iron(III) oxyhydroxides. During anoxic periods, once nitrate was depleted, the reductive dissolution of iron(III) oxyhydroxides released P. However, only 4.5 % of the released P accumulated in solution while the rest was redistributed between the MgCl₂ and NaHCO₃ extractable fractions of the solid phase. Thus, under the short redox fluctuations imposed in the experiments, P remobilization to the aqueous phase remained relatively limited. Orthophosphate predominated at all times during the experiment in both the solid and aqueous phase. Combined P monoesters and diesters accounted for between 9 and 16 % of sediment particulate P. Phosphatase activities up to 2.4 mmol h⁻¹ kg⁻¹ indicated the potential for rapid mineralization of organic P (P_o), in particular during periods of aeration when the activity of phosphomonoesterases was 37 % higher than under N₂ sparging. The results emphasize that the magnitude and timing of internal P loading during periods of anoxia are dependent on both P redistribution within sediments and bottom-water nitrate concentrations.

Hydrophysical properties of peat influence the partitioning of rainfall into infiltration versus runoff, determine water flow and solute transport patterns, and regulate the carbon and nitrogen cycles in peatlands. Compared with mineral soils, our understanding of hydraulic properties of peat soils is limited, especially of the temporal dynamics of peat properties. A data set of peat subsidence as well as the bulk density (BD) change rate following artificial drainage was assembled from the literature. The collected data cover a time period of up to 272 years of land drainage for forestry and agriculture in boreal and temperate climate zones. The results show that the subsidence rate and BD change rate, and hydrophysical properties of peat can be estimated based on land drainage duration and land use. The most severe shift in pore structure of peat occurs within the first 20 years of land drainage. Peatland drainage reduces macroporosity with pore diameter greater than 50 μm, but increases the volume of pores <5 μm. In the long term, peat thickness loss is responsible for more than 80% of water storage loss. In conclusion, the derived functions between subsidence rate, BD change rate, and drainage duration provide a new approach to estimate the hydrophysical properties of peat (pore structure, saturated hydraulic conductivity, specific yield, and soil water storage) on a centennial scale. The derived hydrophysical parameter values can be used for long‐term hydrological modeling, especially if measured hydraulic parameters of peat are not available.

In recent years, there has been a surge in annual plastic production, which has contributed to growing environmental challenges, particularly in the form of microplastics. Effective management of plastic and microplastic waste has become a critical concern, necessitating innovative strategies to address its impact on ecosystems and human health. In this context, catalytic degradation of microplastics emerges as a pivotal approach that holds significant promise for mitigating the persistent effects of plastic pollution. In this article, we critically explored the current state of catalytic degradation of microplastics and discussed the definition of degradation, characterization methods for degradation products, and the criteria for standard sample preparation. Moreover, the significance and effectiveness of various catalytic entities, including enzymes, transition metal ions (for the Fenton reaction), nanozymes, and microorganisms are summarized. Finally, a few key issues and future perspectives regarding the catalytic degradation of microplastics are proposed.