Eadie, B. J.. NOAA - GLERL, eadie@glerl.noaa.gov
, . J.. ,

Lake Michigan is a virtually enclosed basin with a hydraulic residence time of approximately 100 years. Extensive sediment-water coupling during the six month unstratified period has been reported and is required to close large mass-balance inequities for nutrients and contaminants. Recent satellite imagery and sediment trap studies have shown that the majority of sediment resuspension and transport is episodic, primarily in the February-April period. Events in southern Lake Michigan in 1996-98 resuspended more fine-grain sediments (>1MMT) than the estimated total annual external load. Based on water intake turbidity records, the 1998 event was the most intense in 37 years. During the main resuspension event in March, 1998 mass fluxes (<62um particles) in near-coastal traps increased from 16 to 876 g/m2/d and the flux of total phosphorus from 12 to 380 mgP/m2/d. The intensity, duration, and timing (relative to stratification and the beginning of the spring plankton bloom) of these episodic events are being investigated to estimate their impact on lake ecosystems on annual time scales.
Day: Thursday, Feb. 4
Time: 11:45 - 12:00pm
Location: Eldorado Hotel
Code: SS52TH1145E