Sediment Aggregate Structure Regulates Nutrient Cycling and Plant–Microbe Interactions in the Water–Plant–Sediment Continuum

The growing impact of climate change, coupled with the widespread expansion of dam construction, has seriously disrupted the natural hydrological patterns of river-connected lakes. This disruption has led to the emergence of a novel phenomenon known as sediment hardening. This process alters the aggregate fraction of sediments, yet its potential effects on biogeochemical cycling within aquatic ecosystems remain largely unexplored and poorly understood. Here, we investigated how varying sediment aggregate sizes—large macroaggregates (LMA, >2000 μm), small macroaggregates (SMA, 250–2000 μm), and microaggregates (MA,