Zooplankton in offshore Lake Michigan show patchy distributions and vertical movements, which are hard to study with traditional methods. Scientists used a laser tool to study zooplankton in the lake during July and September 2015. They found that zooplankton biomass varied a lot between different areas and depths, with some species moving up and down in the water column at night. The amount of phytoplankton in the water was a big factor in determining where zooplankton were found. This variability in zooplankton distribution could affect how fish that eat plankton find their food in the lake.