Data from: Successive stressors alter microbiome composition and reduce resilience in the eelgrass Zostera marina

Here, we conducted a mesocosm experiment exposing Zostera marina (eelgrass) to fertilized sediments (~70 mg of total nitrogen per 100 g DW sediment-1) for 28 days, followed by a simulated marine heatwave (MHW, 23.3ºC for 15 days) and subsequent storm (25 cm/s flow velocities for 12 days). We demonstrate that eelgrass resistance to nutrient enrichment was driven by specific microbiome shift, particularly enrichment of sulfur-oxidizing bacteria such as Arcobacteraceae (49.2-fold higher) and Sulfurimonadaceae (4.7-fold higher), which likely mitigated sulfide toxicity. In contrast, warming responses were dominated by plant-physiological adjustments. Our results demonstrate that eelgrass resilience depends critically on stressors sequence, where legacy effects alter plant-microbe interactions and physiological responses. While microbial-mediated resistance buffers nutrient stress, thermal acclimation relies on physiological plasticity, highlighting the dual role of ecological memory and temporal stress gradients in seagrass survival. These findings emphasize the need to incorporate both stressor succession and microbiome dynamics into seagrass conservation strategies under climate change.