plant species identity

Plant identity and growth stage shape salt marsh alkalinity export

Vegetated sediments in salt marshes produce nearly twice the alkalinity of unvegetated mudflats, but the effect hinges on which plants are present. In a new mesocosm experiment, *Triglochin maritima* drove porewater alkalinity above 5000 µmol kg⁻¹, while *Puccinellia maritima* matched bare sediment. Species identity and growth stage, not richness, governed alkalinity export. This tight coupling between plant traits and sediment chemistry refines how blue carbon budgets are calculated. For broader context, see our coverage of how salt marsh vegetation boosts organic carbon storage.