Biologically important artificial light at night on the seafloor

Area of Science:

• Marine ecology
• Environmental science
• Oceanography

Background:

• Coastal development is increasing anthropogenic light pollution in marine environments.
• The ecological impacts of artificial light at night (ALAN) on seafloor ecosystems are not fully understood.

Purpose of the Study:

• To quantify artificial light exposure at the sea surface, subsurface, and seafloor of an urbanized temperate estuary.
• To assess the ecological relevance of light pollution reaching the seafloor.

Main Methods:

• Utilized mapping and radiative transfer modeling.
• Incorporated in situ measurements of optical seawater properties.
• Quantified light exposure across different depths in an LED-lit urban estuary.

Main Results:

• Up to 76% of the three-dimensional seafloor area was exposed to biologically important light pollution.
• Exposure to green wavelengths of light was highest.
• Exposure to red wavelengths was nominal.

Conclusions:

• Light pollution from coastal cities significantly impacts seafloor ecosystems.
• Artificial light at night poses a threat to marine ecosystems providing vital ecosystem services.
• Further research is urgently needed to understand the full ecological consequences of seafloor light pollution.