Analysing aquatic invertebrate health in terms of Artificial Light at Night (ALAN)

Farhan Jamil; Chayan Munshi

Abstract:

Introduction:

Artificial Light at Night (ALAN) is a recent concern for researchers working on anthropogenic impacts on the wildlife ecosystem, health, and biodiversity. The concern associated with ALAN in an aquatic ecosystem is that it disrupts the natural dark–light cycle (DLC), which is essential for invertebrate health and maintaining ecological balance. In this study, we attempted to understand those adverse consequences by analysing grooming behaviour, a well-established indicator of neurological stress in animals.

Methodology:

A population of freshwater prawn species (Macrobrachium lamarrei), a highly abundant species in the Asian subcontinent, was considered the model organism for our study. The prawns were exposed to artificial light from the sunset to the morning time (except the natural light exposure during the day time). The collective grooming (CG) pattern in the experimental population was calculated in a real-time kinetic manner. The data were analysed by comparing controlled and ALAN-treated prawns, using their CG percentages.

Results:

The results indicated that being exposed to extended artificial light induces a significant increase in the CG activity in the prawns in comparison to the population with a normal DLC. From the 12th to the 72nd hour, there was an exponential elevation in CG that was higher than in the controlled environment. This was followed by a fluctuating and inconsistent increase until the 5th day. On the 6^th and 7^th days, the CG pattern remained consistent and was still higher than that in the controlled environment.

Conclusion:

This study intends to highlight the physiological health hazards associated with light pollution in a prawn population, emphasizing the stability and biodiversity of the aquatic ecosystem. Precisely, we target the freshwater arthropods which represent the aquatic invertebrates for the assessments of anthropogenic effects on aquatic ecosystems. We want to demonstrate how prolonged artificial light exposure can affect the brain behaviour circuit of Macrobrachium lamarrei.