Benthic: The benthic zone of an aquatic system refers to the bottom surface and water directly above it, often out of the reach of sunlight. Commonly, [invertebrates] live here and feed on [detritus].
Limnetic: The limnic zone of an aquatic system is the open water in the middle of a body of water, at a depth where light still penetrates.
Littoral: The littoral zone is the area of an aquatic system where light can penetrate the water all the way to the [substrate]. This is the 'shore' area, often dominated by vegetation rooted in the substrate and emerging from the water (like cattails).