Periphyton as a nature-based solution for remediation of degraded Zoige alpine wetlands: Process, effects and...

Alpine wetlands are crucial yet fragile ecosystems, with the Zoige alpine wetlands experiencing severe degradation. However, hydrological recovery alone has proven insufficient to restore essential wetland functions and may exacerbate degradation, particularly in nutrient cycling and microbial communities. This highlighting an urgent need for nature-based solutions. Periphyton, which could thrive in plateau and regulate nutrients, presents a promising approach. This study explored the potential of locally sourced periphyton to remediate degraded alpine wetlands, assessing its effects and mechanisms. The results demonstrated that periphyton could create an environment with stable pH and electrical conductivity. More importantly, it enhanced nutrient fixation and bioavailability by increasing the activities of β-glucosidase, urease, and alkaline phosphatase, especially in the surface soil of alpine wetlands. It could be explained by microbiome analysis that periphyton boosted bacterial activity in the soil and improved the stability and complexity of soil bacterial communities. Specifically, periphyton promoted enzyme synthesis, metabolic function, and nutrient circulation at the functional gene level, and Pseudomonas, Bacteroidetes, and Acidobacteria played critical roles in the remediation process. Most importantly, periphyton primarily regulated nutrients within the soil rather than directly introducing them to promote plant growth, with coverage exceeding 280 g/m², yielding optimal physiological and reproductive states for alpine wetland plants. This study provided a potential nature-based solution for the remediation of degraded alpine wetlands.