The dark side of light


Artificial lighting is essential for human activity, especially when it pertains to security. It can however have significant negative impacts on estuarine environments. Estuaries are vital and important ecosystems that host a diverse range of species, many of which require a degree of balance. An excess of artificial light is known to disrupt these habitats, ultimately affecting breeding and feeding cycles, promoting excessive algal growth, and even altering habitat functions.

Artificial lighting can interfere with the natural behaviour of wildlife in estuaries. Many species, such as fish and birds, rely on natural light cues for breeding and feeding. Disruption in these light patterns can lead to disorientation and mismatches in these critical activities, affecting population dynamics.

Excessive artificial light can promote algal growth, which in turn can exacerbate eutrophication in estuaries. Eutrophication is the process in which a water body becomes overly enriched with nutrients, leading to the plentiful growth of simple plant life. Light pollution enables algae to photosynthesize for longer periods, leading to blooms that can deplete oxygen levels in the water, harming aquatic life. Such conditions can create dead zones where few organisms can survive or areas with singular or limited representation of species.

Furthermore, artificial lighting alters both habitat structure and function. Certain species are highly specialised and capitalise on either diurnal (daily) or nocturnal strategies when it comes to predation and or safely feeding. Artificial lighting can

drastically alter these predator-prey dynamics by creating artificial advantages and disadvantages resulting in species becoming more or less active depending on lighting preference. As a result this can have cascading effects throughout the food web, disrupting the balance of the ecosystem.

Residents living near estuaries can take several steps to minimise the impact of artificial lighting on the surrounding environment. Firstly, this can be done by reducing the amount of lights left on at night or by installing motion activated

sensors. These measures reduce the time lights are on, therefore limiting exposure.

Secondly, consider light positioning. By directing light downwards to an estuary, it decreases the spread into estuarine areas. One can also use warm-coloured bulbs, as lighting with lower blue wavelengths is less disruptive to wildlife.

Lastly, consider alternative security devices as opposed to floodlights. Cameras as well as wall mounted motion sensors are arguably more effective in combating crime than a light that is left on.

By adopting these measures, and acknowledging potential impact, residents can help protect the delicate estuarine eco-systems from the adverse effects of artificial lighting. Recognising the importance of coexistence is essential when it comes to ensuring these habitats remain both vibrant and functional for future generations.