Coast Light

Actionable Science to Manage Coastal Nightscapes

Project funded by USC Sea Grant

The southern California region has both extraordinarily diverse and important nearshore and marine biodiversity and some of the brightest night skies on the planet. Management of natural and cultural resources of urban coasts will only be half effective if conditions at night are not considered.

*Setting up a Sky Quality Camera on Santa Monica Beach.*

Artificial light at night disrupts a wide range of natural processes. Recent research has shown significant impacts of coastal lighting reducing foraging of intertidal invertebrates, disrupting marine food webs, suppressing movement of juvenile fishes, increasing predation on nesting seabirds, and increasing the settlement rates of key marine fouling organisms.

The network of managers who plan for and regulate the urban ocean need baseline information and actionable science about the distribution of light pollution along our coast. This research can help with critical questions such as: Can outdoor lighting be managed to reduce impacts such as fouling of hulls and to protect endangered species that use darkness as a refuge? How will the changing spectrum of new lighting technology affect coastal and nearshore marine resources?

Video on the background research that led up to this project (produced by USC Dornsife)

The answers to these questions will be used to provide actionable information to managers seeking to minimize the impacts of artificial light at night:

What is the range of nocturnal illumination experienced at the shoreline across Ventura, Los Angeles, and Orange counties?
What influence does artificial light at night have on the distribution and behavior of species of concern on the urban coast?
Do direct glare and sky glow influence the rate of settlement of marine invertebrate fouling organisms?
Do ambient light conditions affect the geographic distribution of use of the urban coast by sensitive species such as Western Snowy Plovers and California Grunion?

This project will use new tools, techniques, and technologies that are now available to quantify light environments in a way that enables new analysis and allows for connection to management actions, including:

A new satellite with nightly overflights measuring upward light radiance at higher spatial resolution than previous sensors;
Products measuring artificial sky glow (the reflected light in the atmosphere) that integrate satellite-derived measurements with ground-based validation;
Small-format satellites known as CubeSats have been tasked to collect full-spectrum information at higher resolutions than other sensors; and
Hemispherical photography (capturing the full sky from horizon to horizon in each photograph) and new associated software and calibration procedures that remove the light from natural sources (e.g., stars, milky way) to produce a measurement that is only the artificial sources. This system is called the Sky Quality Camera (Euromix Ltd, Llubljana, Slovenia).

From the Field

*Example of output from the Sky Quality Camera from the Cabrillo Boat Ramp across from the Port of Los Angeles.*

Results

Simons, A. L., X. Yin, and T. Longcore. 2020. High correlation but high scale-dependent variance between satellite measured night lights and terrestrial exposure. Environmental Research Communications 2:021006.