Biologically important artificial light at night on the seafloor

Abstract

Accelerating coastal development is increasing the exposure of marine ecosystems to nighttime light pollution, but is anthropogenic light reaching the seafloor in sufficient quantities to have ecological impacts? Using a combination of mapping, and radiative transfer modelling utilising in situ measurements of optical seawater properties, we quantified artificial light exposure at the sea surface, beneath the sea surface, and at the sea floor of an urbanised temperate estuary bordered by an LED lit city. Up to 76% of the three-dimensional seafloor area was exposed to biologically important light pollution. Exposure to green wavelengths was highest, while exposure to red wavelengths was nominal. We conclude that light pollution from coastal cities is likely having deleterious impacts on seafloor ecosystems which provide vital ecosystem services. A comprehensive understanding of these impacts is urgently needed.

Marine artificial light at night: An empirical and technical guide

“…Benthic ecosystems (seagrass, kelp, corals) further modify shallow underwater lightscapes (Ackleson, 2003). Tidal cycles change the path length of natural (Roberts et al, 2018) and artificial (Davies et al, 2020) light on the seafloor and expose intertidal marine organisms up to twice daily to direct light (Figure 2C-F). Tidal amplitudes vary monthly (spring and neap tides) and annually (equinoctial tides) and can range from a few centimetres up to more than 15 meters (Desplanque & Mossman, 2001).…”

“…Measuring biologically relevant ALAN distribution underwater should be guided by organisms' photobiology considering: (i) species' threshold light sensitivity, (ii) species' spectral coverage and resolution (both measured in radiometric units, Table 2), and (iii) the orientation and geometry of an animal's photosensory system (Table 1). If light sensitivity thresholds and spectral sensitivities are lacking, researchers might consider representative thresholds (Davies et al, 2020;Ludvigsen et al, 2018).…”

“…Meter, SQM) designed to measure sunlight above the sea surface (Davies et al, 2020;Ges et al, 2018).…”

Presence of Light Pollution as a Latent Anthropogenic Influence of Bat Dispersal in Mindanao, Philippines

“…In developed countries, light pollution is typically caused by activities that occur over a large geographic area (1) . The emergence of new infectious diseases has increased in the last decade, posing a serious threat to global public health and contributes significantly as a route for nocturnal animals such as bats and rodents (2) as its diversity in the biological response to nature (3) . City lighting growth has been exponential in the last half-century.…”

“…The primary cause of light pollution dispersion and intensity is the increasing number of human population and its corresponding urbanization (3,(8)(9)(10) . Exposure to light pollution influences ecological relationships (11) throughout a wide variety of taxa and has detrimental effects on activities such as hunting, species breeding, and interactions (12) .…”