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Rabalais, N. N., Louisiana Universities Marine Consortium , Cocodrie, USA, nrabalais@lumcon.edu

RACHEL CARSON AWARD LECTURE - SIGNIFICANCE AND INSIGNIFICANCE OF THE 2011 MISSISSIPPI FLOOD TO SURROUNDING WATERS

The flood of the Mississippi River in 2011 broke many freshwater discharge and nutrient load records. The MR drainage contributes 90+% of the sediment, nutrients and fresh water to the northern Gulf of Mexico, and its influence reaches thousands of kilometers away. The record flow forced breaking levees in Missouri and opening major spillways, the Morganza into the Atchafalaya River basin and the Bonnet Carré north of the city of New Orleans into Lake Pontchartrain, and proffered expectations of dense harmful algal blooms in receiving waters and the largest to-date ‘dead zone’ (area of low oxygen) offshore. Not all expectations were realized, with lower than expected chlorophyll biomass and HAB concentrations in Lake Pontchartrain (high flushing and high turbidity) and a smaller area of shelf hypoxia (tropical storm action and ocean currents). More detrimental effects were the severity and volume of low oxygen elsewhere, noxious and harmful algal blooms west and east of the delta, and large, persistent areas of low oxygen east of the delta in summer. The 2011 scenario mirrors climate change expectations for the watershed.

Session #:031
Date: 2/21/2012
Time: 10:30
Location: Ballroom J

Presentation is given by student: No