Which zone is characterized by deep water with little or no light and low oxygen?

Which zone is characterized by deep water with little or no light and low oxygen?

• A. Emergent Plants
• B. Limnetic Zone
• C. Littoral Zone
• D. Profundal Zone

Answer: (D)

Light fades quickly with depth, so the deepest parts of a lake receive little to no light. The zone that sits below the dim open-water layer is the profundal zone. In this deep, dark water, photosynthesis can’t occur because there isn’t enough light, and oxygen tends to be low because mixing with the surface is limited and decomposition uses up the available oxygen. This combination—deep water, very little light, and low oxygen—defines the profundal zone. For context, emergent plants grow in very shallow nearshore margins, the littoral zone is the shallow, wave-swept nearshore where light reaches the bottom and plants thrive, and the limnetic zone is the open-water layer that still receives enough light for photosynthesis.

Light fades quickly with depth, so the deepest parts of a lake receive little to no light. The zone that sits below the dim open-water layer is the profundal zone. In this deep, dark water, photosynthesis can’t occur because there isn’t enough light, and oxygen tends to be low because mixing with the surface is limited and decomposition uses up the available oxygen. This combination—deep water, very little light, and low oxygen—defines the profundal zone. For context, emergent plants grow in very shallow nearshore margins, the littoral zone is the shallow, wave-swept nearshore where light reaches the bottom and plants thrive, and the limnetic zone is the open-water layer that still receives enough light for photosynthesis.