CONSEQUENCES OF THE 1993 MISSISSIPPI RIVER FLOOD IN THE GULF OF MEXICO

摘要

Seasonally severe hypoxia (≤2 mg O_2 l~-1) occurs in waters below the pycnocline on the northern Gulf of Mexico inner continental shelf in May through September over extensive areas (up to 18000 km~2). Spatial and temporal variability in the distribution of hypoxic water masses is related, in part, to the amplitude and phasing of freshwater discharge from the Mississippi and Atchafalaya Rivers, circulation patterns, nutrient flux and a close coupling with net productivity. The Mississippi River flood in 1993 and sustained freshwater inputs to Gulf of Mexico occurred during mid-summer through early autumn when long-term mean flows (1930-1995) are normally lowest.