We collect sediments routinely for both analysis of contaminants as well as nutrients to look at the oxygen demand of the sediment. One of the concerns is that we've had nutrients coming into these lakes...well, they come in naturally so they've been coming in since geologic times, but that addition of nutrients has been exacerbated in recent years. Those nutrients ultimately will settle into the bottom of the lake and as bacteria and other...work over those sediments, they'll consume oxygen. We are concerned about how the lakes differ and how the sediments in the lakes are affected by human activity.
On February 13th, 2014. See this statement in context.