When is the Deep Scattering Layer at its shallowest?

The Deep Scattering Layer (DSL) is a phenomenon observed in the ocean where certain organisms, primarily zooplankton, exhibit a vertical migration pattern. This migration is primarily influenced by light availability and predation risk. At night, the organisms in the DSL rise towards the surface to feed in the upper layers of the ocean, where they are exposed to more light but have less predator presence. As night progresses, the DSL is at its shallowest because many zooplankton species are actively swimming upwards to take advantage of the increased food resources close to the surface.

During the day, these organisms typically descend to deeper waters to avoid predators, making the DSL deeper. Similarly, during dawn and dusk, their vertical movement is affected by the change in light conditions, but it's during the nighttime that the DSL reaches its shallowest point. This behavior is a crucial adaptation for survival and feeding, highlighting the dynamic interaction between light, predation, and feeding strategies in marine ecosystems.