Nutrient regime shift in the western North Atlantic indicated by compound-specific δ15N of deep-sea gorgonian corals

摘要: Despite the importance of nitrogen (N) cycle on marine productivity, little is known about variability in N sources and cycling ocean relation to natural anthropogenic climate change. Beyond last few decades scientific observation, knowledge depends largely proxy records derived from stable isotopes (δ15N) preserved sediments other bioarchives. Traditional bulk δ15N measurements, however, represent combined influence source subsequent trophic transfers, often confounding environmental interpretation. Recently, compound-specific analysis individual amino acids (δ15N-AA) has been shown as a means deconvolve level versus effects organic matter. Here, we demonstrate first use δ15N-AA paleoceanographic study, through annually secreted growth rings endoskeletons deep-sea gorgonian corals. In Northwest Atlantic off Nova Scotia, coral correlated with increasing presence subtropical subpolar slope waters over twentieth century. By using new approach control for variable processing, are able interpret values nitrate and, hence, water partitioning. We conclude that persistence warm, nutrient-rich regime since early 1970s unique context approximately 1,800 yr. This evidence suggests nutrient this region coordinated recent changes global underscores broad potential studies cycle.