Beyond the Nutrient Paradigm: Thermal Intensity and Duration Trigger Opposite Phytoplankton Responses to Marine Heatwaves in the East China Sea Research Code and Data

Overview This repository contains MATLAB scripts for data processing, statistical analysis, and figure generation for a research paper: Beyond the Nutrient Paradigm: Thermal Intensity and Duration Trigger Opposite Phytoplankton Responses to Marine Heatwaves in the East China Sea Research .Coverage includes: Multi-source data preprocessing and grid harmonization MHW event detection and metric calculation Trend analysis and significance testing Chlorophyll-a anomaly analysis and its relationship with MHWs Driver attribution analysis (atmospheric vs oceanic) Regional and global comparative figures Intermediate run-time outputs (.mat) Main Scripts A_data_reshape.m: preprocesses SST, Chl-a, heat flux, MLD, nitrate, and harmonizes grids. B_MHW_detect_plot.m: reads MHW detection outputs, computes seasonal properties, and generates spatial plots. C_MHW_trend.m: analyzes interannual and spatial trends of key MHW metrics. D_Chl_anomaly_calculate.m: computes Chl-a climatology and anomalies (with/without MHW), and produces validation figures. E_Chl_analysis.m: analyzes relationships between Chl-a anomalies and MHW intensity/duration/environmental factors. F_causes.m: performs MHW driver attribution and plotting analysis of MHW properties. G_global_analysis.m: global-scale analysis figures. H_event_threshold.m: sensitivity comparison under different event-threshold schemes. Utility Functions isbetw.m: interval filtering helper. Mann_Kendall.m: Mann-Kendall trend significance test. density2C.m: scatter density estimation and color mapping. Data and Intermediate Results The repository includes part of the intermediate outputs and figures (e.g., *.mat, *.png).Note: several scripts use absolute paths (e.g., E:/Data/...). Please update paths for your local environment before reproduction. Recommended Execution Order A_data_reshape.m B_MHW_detect_plot.m C_MHW_trend.m D_Chl_anomaly_calculate.m E_Chl_analysis.m F_causes.m G_global_analysis.m H_event_threshold.m Suggested Environment MATLAB R2023b or newer (recommended) Depends on m_map-related and other third-party plotting functions (e.g., m_proj, m_pcolor, m_gshhs, nclCM), which can be installed from MathWorks resources Statistics Toolbox functions are used (e.g., fitlm, ttest2, corrcoef) Notes Some scripts are set to load saved intermediate outputs by default. For full recomputation, uncomment relevant sections and prepare source data. In-situ measurement datasets are not uploaded; please contact the corresponding author by email.