Data for the manuscript "Input of Terrigenious Inorganic Nitrogen Biases Marine Stories inferred from Sedimentary Bulk Nitrogen Isotope"

Our study critically reassesses the contributions of terrigenous IN in sedimentary δ¹⁵N_TN and its implications on marine nitrogen cycle interpretations. We employed a novel method combining potassium persulfate oxidation with denitrifying bacteria to quantitatively and isotopically distinguish between ON and IN in various environmental matrices. Our findings reveal substantial contributions of IN to total nitrogen, with IN fractions ranging from 30% to 50%, and isotopic signatures significantly lighter than ON. This discrepancy leads to a significant negative offset in δ¹⁵N_TN, necessitating a reevaluation of historical nitrogen cycle reconstructions traditionally based on δ¹⁵N_TN.