Nitrogen isotopes in otoliths reconstruct ancient trophic position

摘要: The ratio of 15 N/ 14 N( δ N) from consumer and prey tissue is commonly used in ecological studies to determine trophic level, food web structure, mean level aquatic ecosystems. There a predictable positive relationship between the N values caused by bioaccumulation tissues consumers with each step up chain. Reconstructing structure or chain length over time may provide resource managers insights about ecosystem biodiversity resilience. Yet, many marine systems absence baseline information before anthropogenic disturbances makes comparative stud- ies addressing responses extremely diffi- cult. Here we attempt retrospectively reconstruct position four species fish upper Gulf California, Mexico perturbations such as overfishing damming Colorado River. We first validated if otolith approximates observed tissue. then encapsulated ancient otoliths that are 1,000 5,500 years old define structure. Our results suggested has slightly more than soft appropriately defined fishes' relative position. found significant differences functional