Seasonal hypoxia regulates macrobenthic function and structure in the Mississippi Bight

• Hypoxia regulates the function and structure of macrobenthos in the Mississippi Bight.
• Seasonal hypoxia acted as a regular periodic disturbance during the study period.
• Macrobenthic metrics reflected seasonal hypoxia.
• Effects on secondary production and community maturity agree with previous studies.
• Metrics were higher at the 20 m isobath during the latter half of the study period.

Hypoxic conditions are escalating to the east of the Mississippi River within the Mississippi Bight. The objective of this study was to examine changes in macrobenthic function and structure relative to seasonal hypoxia over a 3.5 year period at the 10 m (Site 6) and 20 m (Site 8) isobaths within the Mississippi Bight. Seasonal hypoxia acted as a regular periodic disturbance during the study period, although the magnitude and duration of hypoxia varied inter-annually. Macrobenthic metrics revealed seasonal hypoxia effects on secondary production potential and community maturity, which agrees with previous studies. In addition, metrics were notably higher at the 20 m isobath during the latter half of the study period, following the Deepwater Horizon (DwH) oil spill. This study confirms hypoxia as a major driver affecting the function and structure of soft-bottom macrobenthos in the Mississippi Bight.

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