Isotopic values in oysters indicate elemental sources constrained by multiple gradients

摘要: Abstract Stable nitrogen and carbon isotopes (δ15N δ13C) elemental content (% nitrogen, % carbon) in oysters (Crassostrea virginica) grown by a network of 132 citizen–scientists (11,600 km2, 87.9 km2 site−1) were examined to test effects land use, salinity, flushing time, oyster size on bioindication human and/or animal sources. Oyster δ15N sampled from shallow waters sites throughout Chesapeake Bay its tributaries exhibited nested spatial patterns: (1) decreasing toward the mouth (1000s km2) (2) decreasing, increasing, not changing tributary mouths (100s km2). Distinct isotopic ‘signatures’ associated with composition water quality freshwater streams, sources, marine vs. terrestrial Yet at 1000s km2, varied bioindicator size, thus constraining upper extent for inferring sources scale gradients these confounding physical biological factors. Nevertheless, 100s km2 can be used infer nutrient transport mechanisms might have implications fishery management/enforcement. Ultimately, δ13C bioindicators distributed may add substantial value existing ongoing programs, networks, monitoring databases, some use imputing data gaps where intensive is lacking.