The near-surface open water surrounded by the littoral zone is the limnetic zone.    From Wordnik.com.  [Freshwater biomes] Reference

Little light penetrates all the way through the limnetic zone into the profundal zone.    From Wordnik.com.  [Freshwater biomes] Reference

The limnetic zone is well-lighted (like the littoral zone) and is dominated by plankton, both phytoplankton and zooplankton.    From Wordnik.com.  [Freshwater biomes] Reference

However, in a few localities, an inverse process has been observed, such as in Caño Mánamo (Delta Amacuro), where mangroves have expanded at a rate of 6 - 7 ha/year since 1965, when a cofferdam was built, leading to the salinization of the formerly limnetic waters.    From Wordnik.com.  [Coastal Venezuelan mangroves] Reference

The UBC study involved new species found in British Columbia lakes that have evolved distinct physical traits: limnetic sticklebacks (smaller open water dwellers with narrow mouths), benthic sticklebacks (larger bottom dwellers with a wide gape) and a generalist species to represent the probable ancestor of the two species.    From Wordnik.com.  [EurekAlert! - Breaking News] Reference

Limnology and limnetic ecology.    From Wordnik.com.  [Featured Articles - Encyclopedia of Earth] Reference