Stable carbon isotope amino acids fingerprints of estuarine and freshwater macrophyte and terrestrial primary producers

Plant material was collected from aquatic and terrestrial environments from the Sacramento-San Joaquin River Delta. Carbon isotope values of bulk plant tissue and individual amino acids were measured. Fifty-five specimens were collected, including trees, shrubs, forbs, and grasses as well as floating, submerged, and emergent aquatic plants. Bulk tissues were processed and the carbon isotope values were measured following Tipple and Ehleringer, 2018 (Oecologia, 187, 1053-1075). Amino acids were hydrolyzed, derivatized, and isolated following Vokhshoori et al., 2013 (Marine Ecology Progress Series, 504, 59-72). Carbon isotope values of individual amino acids were measured following Vokhshoori et al., 2013. The purpose of this study was to assess if amino acid fingerprints of macrophyte primary producers were distinct from those of marine primary producers and terrestrial vascular plant species. The goal of this study was to provide a benchmark dataset for the next generation of food web monitoring programs within estuarine and mixed source environments.