Probing Particle Processes in Lake Michigan Using Sediment Traps

Sediment trap sampling at an offshore site in southern Lake Michigan has continued for an 18 year period with a sampling frequency ranging from weekly to semi-annually. During the 6 month unstratified period sediment trap mass and tracer profiles are nearly constant and they have been used to describe the extent of sediment resuspension. After stratification, mass flux rapidly declines and particle tracers are removed from the epilimnion at the rate of 0.5–1 m.d¹. Exponential profiles of mass flux clearly show the persistence of a benthic nepheloid layer. High frequency sampling with near-bottom sequencing traps show order of magnitude ranges in mass flux over a few day period.