Quantifying Critical Thresholds of Submerged Macrophyte Coverage to Buffer Climate-Amplified Ammonium Pulses and Stabilize Clear-water States

作者：Chaochao Lv, Lei Shi, Yuqing Tian, Hang Shan, Qingchuan Chou, Wei Liu, Kuanyi Li, Te Cao · 发表于：Environmental Science & Technology · 年份：2025 · DOI：10.1021/acs.est.5c04237 · 被引用次数：8 · 研究领域：Aquatic Ecosystems and Phytoplankton Dynamics、Marine and coastal ecosystems、Coastal wetland ecosystem dynamics

Climate change intensifies nutrient pulses through extreme rainfall and agricultural runoff, yet the buffering capacity of submerged macrophytes against such disturbances remains unquantified. Through a large-scale enclosure experiment simulating ammonium pulses (1.24 mg/L NH 4 –N), we tested how submerged macrophytes coverage (SMC, 0–100%) modulates water quality, ecosystem resilience, and regime shifts (from clear to turbid). The system’s buffering capacity and resilience stability increased significantly with SMC, whereas its recovery stability decreased. High SMC (>50%) accelerated NH 4 –N removal (96 h vs 168 h in controls), suppressed phytoplankton blooms (Chl- a increase: 102.5% vs 237.4%), and sustained clear water. Conversely, low and medium SMC (<50%) did not prevent transitions to algal-dominated states. Furthermore, NH 4 –N stress was inversely correlated with SMC, and persistently high NH 4 –N at low SMC increased macrophyte degradation risk. Structural equation modeling revealed that macrophytes-mediated nutrient competition and light stabilization underpinned these effects. Additionally, we identify a critical SMC threshold (39–51%) to mitigate pulse impacts─a finding urgently needed to guide lake restoration in a changing climate. This work bridges the gap between pulse ecology and adaptive management, offering actionable strategies for SDG 6 (Clean Water) and 13 (Climate Action).