Artificial Light at Night Alleviates the Negative Effect of Pb on Freshwater Ecosystems.

Gaozhong Pu,Danjuan Zeng,Jianxiong Liao,Ling Mo,Xiaxia Chen

doi:10.3390/ijms20061343

Abstract

Artificial light at night (ALAN) is an increasing phenomenon worldwide that can cause a series of biological and ecological effects, yet little is known about its potential interaction with other stressors in aquatic ecosystems. Here, we tested whether the impact of lead (Pb) on litter decomposition was altered by ALAN exposure using an indoor microcosm experiment. The results showed that ALAN exposure alone significantly increased leaf litter decomposition, decreased the lignin content of leaf litter, and altered fungal community composition and structure. The decomposition rate was 51% higher in Pb with ALAN exposure treatments than in Pb without ALAN treatments, resulting in increased microbial biomass, β-glucosidase (β-G) activity, and the enhanced correlation between β-G and litter decomposition rate. These results indicate that the negative effect of Pb on leaf litter decomposition in aquatic ecosystems may be alleviated by ALAN. In addition, ALAN exposure also alters the correlation among fungi associated with leaf litter decomposition. In summary, this study expands our understanding of Pb toxicity on litter decomposition in freshwater ecosystems and highlights the importance of considering ALAN when assessing environmental metal pollutions.

Highlights

With the continued global growth of anthropogenic activities, there are emerging pollutants [1,2,3]
These results indicated that Artificial light at night (ALAN) can alter the fungal community composition and structure associated with leaf litter decomposition in aquatic ecosystems
Another important insight from our experiments is that the negative effect of Pb on the leaf litter decomposition of P. stenoptera was alleviated by ALAN

Summary

Introduction

With the continued global growth of anthropogenic activities, there are emerging pollutants (e.g., artificial light at night/ALAN, engineered nanoparticles and pharmaceuticals, and personal care products) [1,2,3] These emerging pollutants directly affect organisms and ecosystems, and interact and synergize with other environmental pressures (such as heavy metal pollution), leading to more complex effects [4]. Studies on the effects of ALAN in aquatic systems have shown that ALAN affects the physiological and behavioral responses of individual species and predation [3,12,13], and alters community compositions of periphyton and sediment microbes, with implications for ecosystem level functions [5,14,15] Studies in this field have addressed the negative effects of ALAN on different species or communities, there is a lack of research on the effects of ALAN on some important ecological processes in the aquatic ecosystem, such as plant litter decomposition, and associated microbial community activities. They are sensitive to contaminants and can provide a suitable model to assess contaminant effects on complex freshwater ecological systems [1,17]

Methods

Results

Discussion

Conclusion