How does Arctic sea ice reduce sunlight available to marine life?

Arctic sea ice reduces the amount of sunlight available to marine life primarily by acting as a physical barrier and a reflective surface.

• Reflection of Solar Radiation: Snow and ice possess a high albedo, meaning they reflect a significant proportion of incoming solar radiation back into the atmosphere rather than allowing it to penetrate the water column.12
• Physical Obstruction: The presence of a persistent ice pack creates a physical cover that greatly reduces the penetration of sunlight into the ocean.3

Because marine life, such as phytoplankton and algae, relies on these light levels for photosynthesis, the reduction of solar energy caused by sea ice cover limits the productivity of these organisms. While some algae are adapted to live within the ice itself, the overall decrease in available light energy generally restricts the biological productivity of the underlying water.1435