Unlike many terrestrial ecosystems, access to the marine world for even simple observation is hindered by the physical constraints of light attenuation, pressure, and the need to be immersed in a corrosive environment. As such, understanding marine ecosystems has always been limited by a lack of tools. Over several decades, Dr. Jaffe has collaborated with marine ecologists to design, fabricate, deploy, and analyze data from an ensemble of subsea systems that record information about organisms on a multitude of scales.In the case of zooplankton, several sonar systems were used to gain behavioral insights into both diel migration and apparent concentration of near shore animals in downwellings. In the case of phytoplankton, a planar laser imaging fluorometer was developed to infer a transition from seemingly random distributions on centimeter scales to the presences of thin layers on meter scales. In order to address even smaller scales, a new project to study protist behavior in-situ with an underwater 3-dimensional video microscope has just begun that promises to provide novel insights into the behavioral responses or organisms at these even-smaller scales.