Climate variability and extremes, interacting with nitrogen storage, amplify eutrophication risk

Geophysical Research Letters
By: , and 

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Abstract

Despite 30 years of basin-wide nutrient-reduction efforts, severe hypoxia continues to be observed in the Chesapeake Bay. Here we demonstrate the critical influence of climate variability, interacting with accumulated nitrogen (N) over multidecades, on Susquehanna River dissolved nitrogen (DN) loads, known precursors of the hypoxia in the Bay. We used the process model LM3-TAN (Terrestrial and Aquatic Nitrogen), which is capable of capturing both seasonal and decadal-to-century changes in vegetation-soil-river N storage, and produced nine scenarios of DN-load distributions under different short-term scenarios of climate variability and extremes. We illustrate that after 1 to 3 yearlong dry spells, the likelihood of exceeding a threshold DN load (56 kt yr−1) increases by 40 to 65% due to flushing of N accumulated throughout the dry spells and altered microbial processes. Our analyses suggest that possible future increases in climate variability/extremes—specifically, high precipitation occurring after multiyear dry spells—could likely lead to high DN-load anomalies and hypoxia.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Climate variability and extremes, interacting with nitrogen storage, amplify eutrophication risk
Series title Geophysical Research Letters
DOI 10.1002/2016GL069254
Volume 43
Issue 14
Year Published 2016
Language English
Publisher American Geophysical Union
Publisher location Washington, D.C.
Contributing office(s) National Research Program - Eastern Branch
First page 7520
Last page 7528
Country United States
Other Geospatial Chesapeake Bay