Biological and physiological responses of Phyllospadix scouleri to simulated marine heatwaves

This dataset contains the raw and processed biological data supporting the study on the physiological responses of the surfgrass Phyllospadix scouleri under simulated marine heatwave conditions. The experiment evaluated the effects of three temperature treatments—control (18.5 ± 1.5°C), severe marine heatwave (23.5 ± 1.5°C), and extreme marine heatwave (26.5 ± 1.5°C)—across two experimental phases: warming and post-warming (recovery). Measurements were conducted on independent biological replicates (n = 4 per treatment × phase combination). The dataset includes ecophysiological descriptors spanning multiple functional domains: Photosynthesis and respiration: net and gross photosynthetic rates, respiration rate, photosynthesis–irradiance parameters (e.g., Pmax, Ek, α, Ec) Photophysiology: maximum and effective quantum yield (Fv/Fm, ΦPSII), electron transport rate (ETR), fluorescence parameters (F0, Fm), and non-photochemical quenching (NPQ) Nitrogen metabolism: nitrate uptake rates and nitrate reductase activity (NRA) Biochemical composition: chlorophyll a and b, carotenoids, phenolic content, antioxidant capacity Oxidative stress and damage: lipid peroxidation (MDA equivalents) Carbon balance and growth: non-structural carbohydrates (NSC), daily productivity (DP), and relative growth rate (RGR) Each observation is associated with metadata including treatment, experimental phase, and replicate identity. Data structure The dataset is provided as an Excel file containing: One sheet with biological response variables Columns representing: Treatment (Control, Severe-MHW, Extreme-MHW) Experimental phase (Warming, Post-warming) Measured variables Usage notes Values represent individual replicate measurements used in statistical analyses (ANOVA, PCA, PERMANOVA) reported in the associated manuscript. Units are consistent with those described in the manuscript methods and figure legends. Missing values correspond to measurements not available for specific variables or samples. Related publication This dataset supports the manuscript: Vivanco-Bercovich et al. (2026). Crossing thermal limits: functional collapse of the surfgrass Phyllospadix scouleri under simulated extreme marine heatwaves. Journal of Experimental Botany.