{"id":177490,"date":"2025-11-12T23:50:21","date_gmt":"2025-11-12T23:50:21","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/177490\/"},"modified":"2025-11-12T23:50:21","modified_gmt":"2025-11-12T23:50:21","slug":"widespread-influence-of-artificial-light-at-night-on-ecosystem-metabolism","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/177490\/","title":{"rendered":"Widespread influence of artificial light at night on ecosystem metabolism"},"content":{"rendered":"<p>Artificial light pollution is accelerating across the globe<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 1\" title=\"Kyba, C. C. M. et al. Artificially lit surface of Earth at night increasing in radiance and extent. Sci. Adv. 3, e1701528 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR1\" id=\"ref-link-section-d68418405e322\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 2\" title=\"Linares Arroyo, H. et al. Monitoring, trends and impacts of light pollution. Nat. Rev. Earth Environ. 5, 417&#x2013;430 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR2\" id=\"ref-link-section-d68418405e325\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a> and has widespread consequences for people<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 3\" title=\"Xue, P., N&#xF4;ga, D. A. &amp; Benedict, C. The dark side of light: light at night may raise the risk of type 2 diabetes. Lancet Reg. Health Eur. 42, 100955 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR3\" id=\"ref-link-section-d68418405e329\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 4\" title=\"Jones, R. R. Exposure to artificial light at night and risk of cancer: where do we go from here?. Br. J. Cancer 124, 1467&#x2013;1468 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR4\" id=\"ref-link-section-d68418405e332\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a> and the planet<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"J&#xE4;gerbrand, A. K. &amp; Spoelstra, K. Effects of anthropogenic light on species and ecosystems. Science 380, 1125&#x2013;1130 (2023).\" href=\"#ref-CR5\" id=\"ref-link-section-d68418405e336\">5<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Sanders, D., Frago, E., Kehoe, R., Patterson, C. &amp; Gaston, K. J. A meta-analysis of biological impacts of artificial light at night. Nat. Ecol. Evol. 5, 74&#x2013;81 (2021).\" href=\"#ref-CR6\" id=\"ref-link-section-d68418405e336_1\">6<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 7\" title=\"Cieraad, E., Strange, E., Flink, M., Schrama, M. &amp; Spoelstra, K. Artificial light at night affects plant&#x2013;herbivore interactions. J. Appl. Ecol. 60, 400&#x2013;410 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR7\" id=\"ref-link-section-d68418405e339\" rel=\"nofollow noopener\" target=\"_blank\">7<\/a>. Shifts in the luminance and spectral composition of the nocturnal environment modify the physiology, behaviour and ecological interactions of organisms<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Cieraad, E., Strange, E., Flink, M., Schrama, M. &amp; Spoelstra, K. Artificial light at night affects plant&#x2013;herbivore interactions. J. Appl. Ecol. 60, 400&#x2013;410 (2023).\" href=\"#ref-CR7\" id=\"ref-link-section-d68418405e343\">7<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Liu, J. A., Mel&#xE9;ndez-Fern&#xE1;ndez, O. H., Bumgarner, J. R. &amp; Nelson, R. J. Effects of light pollution on photoperiod-driven seasonality. Horm. Behav. 141, 105150 (2022).\" href=\"#ref-CR8\" id=\"ref-link-section-d68418405e343_1\">8<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Owens, A. C. S. et al. Light pollution is a driver of insect declines. Biol. Conserv. 241, 108259 (2020).\" href=\"#ref-CR9\" id=\"ref-link-section-d68418405e343_2\">9<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Gaston, K. J., Davies, T. W., Nedelec, S. L. &amp; Holt, L. A. Impacts of artificial light at night on biological timings. Annu. Rev. Ecol. Evol. Syst. 48, 49&#x2013;68 (2017).\" href=\"#ref-CR10\" id=\"ref-link-section-d68418405e343_3\">10<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 11\" title=\"Knop, E. et al. Artificial light at night as a new threat to pollination. Nature 548, 206&#x2013;209 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR11\" id=\"ref-link-section-d68418405e346\" rel=\"nofollow noopener\" target=\"_blank\">11<\/a>, which together play a fundamental role in ecosystem metabolism<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 12\" title=\"Weyhenmeyer, G. A. Toward a fundamental understanding of ecosystem metabolism responses to global warming. One Earth 7, 1886&#x2013;1898 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR12\" id=\"ref-link-section-d68418405e350\" rel=\"nofollow noopener\" target=\"_blank\">12<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 13\" title=\"Schramski, J. R., Dell, A. I., Grady, J. M., Sibly, R. M. &amp; Brown, J. H. Metabolic theory predicts whole-ecosystem properties. Proc. Natl Acad. Sci. USA 112, 2617&#x2013;2622 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR13\" id=\"ref-link-section-d68418405e353\" rel=\"nofollow noopener\" target=\"_blank\">13<\/a>. Ecosystem metabolism, comprising gross primary production (GPP) and ecosystem respiration (Re), directs the magnitude and direction of carbon\u2013climate feedbacks via net ecosystem exchange (NEE)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 14\" title=\"Weiskopf, S. R. et al. Biodiversity loss reduces global terrestrial carbon storage. Nat. Commun. 15, 4354 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR14\" id=\"ref-link-section-d68418405e362\" rel=\"nofollow noopener\" target=\"_blank\">14<\/a>. Around one quarter of global terrestrial ecosystems are exposed to artificial light at night (ALAN)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 15\" title=\"Falchi, F. et al. The new world atlas of artificial night sky brightness. Sci. Adv. 2, e1600377 (2016).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR15\" id=\"ref-link-section-d68418405e366\" rel=\"nofollow noopener\" target=\"_blank\">15<\/a>, but the effects on ecosystem metabolism are currently unknown.<\/p>\n<p>Changing daily and seasonal cycles of light and dark<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 10\" title=\"Gaston, K. J., Davies, T. W., Nedelec, S. L. &amp; Holt, L. A. Impacts of artificial light at night on biological timings. Annu. Rev. Ecol. Evol. Syst. 48, 49&#x2013;68 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR10\" id=\"ref-link-section-d68418405e373\" rel=\"nofollow noopener\" target=\"_blank\">10<\/a> could decouple the timing of biological processes across trophic networks<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 16\" title=\"Maggi, E. et al. Artificial light at night erases positive interactions across trophic levels. Funct. Ecol. 34, 694&#x2013;706 (2020).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR16\" id=\"ref-link-section-d68418405e377\" rel=\"nofollow noopener\" target=\"_blank\">16<\/a>. Trophic groups are also exposed to ALAN at different intensities and have varying sensitivities to luminance and spectral composition<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 17\" title=\"Gaston, K. J., Visser, M. E. &amp; H&#xF6;lker, F. The biological impacts of artificial light at night: the research challenge. Philos. Trans. R. Soc. B 370, 20140133 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR17\" id=\"ref-link-section-d68418405e381\" rel=\"nofollow noopener\" target=\"_blank\">17<\/a>. Plant responses to photoperiod are influenced even at low ALAN intensities<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 18\" title=\"Runkle, E., Heins, R., Cameron, A. &amp; Carlson, W. Flowering of herbaceous perennials under various night interruption and cyclic lighting treatments. HortScience 33, 672&#x2013;677 (1998).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR18\" id=\"ref-link-section-d68418405e385\" rel=\"nofollow noopener\" target=\"_blank\">18<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 19\" title=\"Blanchard, M. G. &amp; Runkle, E. S. Intermittent light from a rotating high-pressure sodium lamp promotes flowering of long-day plants. HortScience 45, 236&#x2013;241 (2010).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR19\" id=\"ref-link-section-d68418405e388\" rel=\"nofollow noopener\" target=\"_blank\">19<\/a>, and longer-term exposure influences seasonal phenology, growth form, resource allocation and, thus, potentially carbon fixation<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 20\" title=\"Bennie, J., Davies, T. W., Cruse, D. &amp; Gaston, K. J. Ecological effects of artificial light at night on wild plants. J. Ecol. 104, 611&#x2013;620 (2016).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR20\" id=\"ref-link-section-d68418405e392\" rel=\"nofollow noopener\" target=\"_blank\">20<\/a>. High ALAN intensity exposure in urban areas disrupts the behavioural patterns of nocturnally migrating birds<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 21\" title=\"Van Doren, B. M. et al. High-intensity urban light installation dramatically alters nocturnal bird migration. Proc. Natl Acad. Sci. USA 114, 11175&#x2013;11180 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR21\" id=\"ref-link-section-d68418405e397\" rel=\"nofollow noopener\" target=\"_blank\">21<\/a> and plant diversity<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 22\" title=\"Stanhope, J., Liddicoat, C. &amp; Weinstein, P. Outdoor artificial light at night: a forgotten factor in green space and health research. Environ. Res. 197, 111012 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR22\" id=\"ref-link-section-d68418405e401\" rel=\"nofollow noopener\" target=\"_blank\">22<\/a> and restructures soil microbial communities, reducing the functional genes involved in nutrient regulation and plant health<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 23\" title=\"Li, X.-M. et al. Artificial light at night triggers negative impacts on nutrients cycling and plant health regulated by soil microbiome in urban ecosystems. Geoderma 436, 116547 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR23\" id=\"ref-link-section-d68418405e405\" rel=\"nofollow noopener\" target=\"_blank\">23<\/a>. Together, the observed effects of ALAN across levels of biological organization and diverse taxa suggest a potential cascading impact on ecosystem structure and function. Previous studies of ALAN effects, however, have focused on local or experimental manipulations, leaving uncertainty about whether ALAN effects persist at the ecosystem level and longer timescales.<\/p>\n<p>GPP and Re are fundamentally constrained by shortwave (solar) radiation (SW) and temperature (T), respectively<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Nemani, R. R. et al. Climate-driven increases in global terrestrial net primary production from 1982 to 1999. Science 300, 1560&#x2013;1563 (2003).\" href=\"#ref-CR24\" id=\"ref-link-section-d68418405e419\">24<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Enquist, B. J. et al. Scaling metabolism from organisms to ecosystems. Nature 423, 639&#x2013;642 (2003).\" href=\"#ref-CR25\" id=\"ref-link-section-d68418405e419_1\">25<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 26\" title=\"Johnston, A. S. A. et al. Temperature thresholds of ecosystem respiration at a global scale. Nat. Ecol. Evol. 5, 487&#x2013;494 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR26\" id=\"ref-link-section-d68418405e422\" rel=\"nofollow noopener\" target=\"_blank\">26<\/a>. That is, SW determines the direction and duration of energy flow between the atmosphere and ecosystems, and T determines the rate of reactions<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 12\" title=\"Weyhenmeyer, G. A. Toward a fundamental understanding of ecosystem metabolism responses to global warming. One Earth 7, 1886&#x2013;1898 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR12\" id=\"ref-link-section-d68418405e429\" rel=\"nofollow noopener\" target=\"_blank\">12<\/a>. Although ALAN is not expected to influence SW or T directly, artificial light could disrupt the processing of energy according to these fundamental constraints via acclimation, compensation and adaptation strategies<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 27\" title=\"Kehoe, R., Sanders, D. &amp; van Veen, F. J. Towards a mechanistic understanding of the effects of artificial light at night on insect populations and communities. Curr. Opin. Insect Sci. 53, 100950 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR27\" id=\"ref-link-section-d68418405e437\" rel=\"nofollow noopener\" target=\"_blank\">27<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 28\" title=\"Altermatt, F. &amp; Ebert, D. Reduced flight-to-light behaviour of moth populations exposed to long-term urban light pollution. Biol. Lett. 12, 20160111 (2016).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR28\" id=\"ref-link-section-d68418405e440\" rel=\"nofollow noopener\" target=\"_blank\">28<\/a>. A better understanding of the magnitude and direction of ALAN effects on ecosystem metabolism could help constrain carbon\u2013climate processes in Earth system models (ESMs)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 29\" title=\"O&#x2019;Sullivan, M. et al. Process-oriented analysis of dominant sources of uncertainty in the land carbon sink. Nat. Commun. 13, 4781 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR29\" id=\"ref-link-section-d68418405e444\" rel=\"nofollow noopener\" target=\"_blank\">29<\/a>. Specifically, largely uncertain ESM processes and their response to climatic factors could be compounded by the chronic effects of pervasive anthropogenic stressors, such as ALAN.<\/p>\n<p>Global efforts to measure carbon exchange across diverse ecosystems<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 30\" title=\"Pastorello, G. et al. The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data. Sci. Data 7, 225 (2020).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR30\" id=\"ref-link-section-d68418405e451\" rel=\"nofollow noopener\" target=\"_blank\">30<\/a> combined with satellite observations of ALAN distribution and intensity across the land surface<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 2\" title=\"Linares Arroyo, H. et al. Monitoring, trends and impacts of light pollution. Nat. Rev. Earth Environ. 5, 417&#x2013;430 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR2\" id=\"ref-link-section-d68418405e455\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 31\" title=\"S&#xE1;nchez de Miguel, A., Bennie, J., Rosenfeld, E., Dzurjak, S. &amp; Gaston, K. J. First estimation of global trends in nocturnal power emissions reveals acceleration of light pollution. Remote Sens. 13, 3311 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR31\" id=\"ref-link-section-d68418405e458\" rel=\"nofollow noopener\" target=\"_blank\">31<\/a> enable the exploration of artificial light\u2019s influence on terrestrial ecosystem metabolism. Here, we leverage the harmonized nighttime light dataset of Li et al.<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 32\" title=\"Li, X., Zhou, Y., Zhao, M. &amp; Zhao, X. A harmonized global nighttime light dataset 1992&#x2013;2018. Sci. Data 7, 168 (2020).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR32\" id=\"ref-link-section-d68418405e462\" rel=\"nofollow noopener\" target=\"_blank\">32<\/a> and eddy covariance observations from FLUXNET2015<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 30\" title=\"Pastorello, G. et al. The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data. Sci. Data 7, 225 (2020).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR30\" id=\"ref-link-section-d68418405e466\" rel=\"nofollow noopener\" target=\"_blank\">30<\/a> to investigate the instantaneous and aggregated influence of ALAN on ecosystem-scale NEE, GPP and Re fluxes. Although both datasets have global coverage, the location of eddy covariance flux towers are biased towards dark sky regions (Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig6\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>). Following definitions by Li et al.<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 32\" title=\"Li, X., Zhou, Y., Zhao, M. &amp; Zhao, X. A harmonized global nighttime light dataset 1992&#x2013;2018. Sci. Data 7, 168 (2020).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR32\" id=\"ref-link-section-d68418405e478\" rel=\"nofollow noopener\" target=\"_blank\">32<\/a> and others<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 33\" title=\"Zhou, Y., Li, X., Asrar, G. R., Smith, S. J. &amp; Imhoff, M. A global record of annual urban dynamics (1992&#x2013;2013) from nighttime lights. Remote Sens. Environ. 219, 206&#x2013;220 (2018).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR33\" id=\"ref-link-section-d68418405e482\" rel=\"nofollow noopener\" target=\"_blank\">33<\/a>, we use three digital number (DN, higher values represent greater luminance of light at night; <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"section anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Sec2\" rel=\"nofollow noopener\" target=\"_blank\">Methods<\/a>) groups representative of low (DN\u2009Methods; Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1a,d<\/a>). Within both North America and Europe, sites were selected on the basis of latitudinal ranges at which medium or high ALAN intensity sites were present (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1b,e<\/a>) to minimize climatic factors in higher or lower latitude sites being ascribed to low ALAN intensities. In total, 86 FLUXNET2015 sites were selected, 34 sites in North America (4, 5 and 25 sites at high, medium and low ALAN intensities, respectively) and 52\u2009sites in Europe (13, 17 and 22\u2009sites at high, medium and low ALAN intensities, respectively) (<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"section anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Sec2\" rel=\"nofollow noopener\" target=\"_blank\">Methods<\/a>; Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a> and Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>). Despite regional imbalances in FLUXNET2015 site distribution across ALAN intensity levels, the dataset captures a diverse range of ALAN intensities across temperate regions experiencing similar seasonal fluctuations in T and SW.<\/p>\n<p><b id=\"Fig1\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 1: Distribution of flux tower sites across artificial light intensity in North America and Europe.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41558-025-02481-0\/figures\/1\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig1\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/11\/41558_2025_2481_Fig1_HTML.png\" alt=\"figure 1\" loading=\"lazy\" width=\"685\" height=\"398\"\/><\/a><\/p>\n<p><b>a<\/b>,<b>d<\/b>, The location of 86 eddy covariance flux tower sites from FLUXNET2015 (symbols, colours indicate ALAN intensity according to DN (higher values represent greater luminance of light at night) (as in <b>d<\/b>) displayed over a harmonized global nighttime light map for 2012 (for visualization only) in North America (n\u2009=\u200934) (<b>a<\/b>) and Europe (n\u2009=\u200952) (<b>d<\/b>). <b>b<\/b>,<b>e<\/b>, The latitudinal distribution of sites with different ALAN intensities for North America (<b>b<\/b>) and for Europe (<b>e<\/b>), in 2\u00b0\u2009N intervals. <b>c<\/b>,<b>f<\/b>, The ALAN intensities of selected FLUXNET2015 sites, averaged across site years (the number of years with observational data per site), for North America (<b>c<\/b>) and Europe (<b>f<\/b>) according to DN with symbol size indicating number of site years (range: 1\u201320\u2009years per site between 1992 and 2014, total site years in <b>c<\/b> is 211 and in <b>f<\/b> is 412). Basemaps in <b>a<\/b> and <b>d<\/b> were generated with QGIS using the harmonized global nighttime light dataset<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 32\" title=\"Li, X., Zhou, Y., Zhao, M. &amp; Zhao, X. A harmonized global nighttime light dataset 1992&#x2013;2018. Sci. Data 7, 168 (2020).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR32\" id=\"ref-link-section-d68418405e582\" rel=\"nofollow noopener\" target=\"_blank\">32<\/a> under a Creative Commons license <a href=\"http:\/\/creativecommons.org\/licenses\/by\/4.0\/\" rel=\"nofollow noopener\" target=\"_blank\">CC BY 4.0<\/a>.<\/p>\n<p>To detect the potential influence of ALAN on ecosystem metabolism, we investigate half-hourly and mean daily ecosystem carbon fluxes (Fc; Fc: NEE, GPP and Re) measurements against their fundamental constraints, T and SW, according to the modified Arrhenius equation of Weyhenmeyer<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 12\" title=\"Weyhenmeyer, G. A. Toward a fundamental understanding of ecosystem metabolism responses to global warming. One Earth 7, 1886&#x2013;1898 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR12\" id=\"ref-link-section-d68418405e621\" rel=\"nofollow noopener\" target=\"_blank\">12<\/a>:<\/p>\n<p>$${F}_{{\\rm{c}}}={T}^{4}\\sigma {{\\rm{e}}}^{\\frac{-\\mathrm{SW}}{\\sigma {T}^{4}}}{k}_{{F}_{{\\rm{c}}}}-b,$$<\/p>\n<p>\n                    (1)\n                <\/p>\n<p>where Fc is ecosystem C flux (NEE, GPP, Re) (in \u00b5mol\u2009CO2\u2009m\u22122\u2009s\u22121), T is temperature in Kelvin, \u03c3 is the Stefan\u2013Boltzmann constant (in J\u2009m\u22122\u2009s\u22121\u2009K\u22124) (5.67\u2009\u00d7\u200910\u22128), SW is incoming SW (in J\u2009m\u22122\u2009s\u22121,) kFc is the slope of the linear relationship and b is the intercept. The function establishes a biophysically grounded baseline for different Fc by capturing their shared fundamental constraints (T and SW). The use of the modified Arrhenius function in this study primarily serves as a comparative baseline rather than a mechanistic model, enabling deviations attributable to chronic ALAN effects to be identified relative to fundamental energetic constraints.<\/p>\n<p>The null models for NEE, GPP and Re were linear mixed effect models (LMMs) or generalized additive mixed models (GAMMs) fitted to equation (<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"equation anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Equ1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>) (<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"section anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Sec2\" rel=\"nofollow noopener\" target=\"_blank\">Methods<\/a>) with FLUXNET2015 site and latitude as random effects and fundamental constraint (\\({T}^{4}\\sigma \\,{{\\rm{e}}}^{\\frac{-\\mathrm{SW}}{\\sigma {T}^{4}}}\\), J\u2009m\u22122\u2009s\u22121) as a fixed effect (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>). The null models were tested against models with additional explanatory variables, including continent, climate, International Geosphere\u2013Biosphere Programme land use classifications, growing season (GS), night duration (ND, hours), vapour pressure deficit (VPD, hectopascals), precipitation (P, millimetres), ALAN intensity (DN), distance to nearest urban polygon (DtNUP, kilometres) and proportion of urban land cover in 3- and 10-km buffers around each site (pULC_3km, pULC_10km). The LMM selection criteria for explanatory variables followed a trade-off between explanatory power and parsimony, with the condition that additional degrees of freedom (df) were accompanied by lower Akaike information criteria (AIC) and higher marginal R2 (R2m) goodness-of-fit measures (\u0394AICdf\u2009R2mdf\u2009&gt;0.01 compared with the null model (<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"section anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Sec2\" rel=\"nofollow noopener\" target=\"_blank\">Methods<\/a>; Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2a,c,e<\/a>). All Fc LMMs selected GS; GPP and Re LMMs selected ND; the GPP LMM selected DtNUP; and the Re LMM selected VPD and ALAN (Supplementary Tables <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a>).<\/p>\n<p><b id=\"Fig2\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 2: Ecosystem carbon flux dependence on modified Arrhenius constraints and the effect of ALAN.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41558-025-02481-0\/figures\/2\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig2\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/11\/41558_2025_2481_Fig2_HTML.png\" alt=\"figure 2\" loading=\"lazy\" width=\"685\" height=\"933\"\/><\/a><\/p>\n<p><b>a<\/b>,<b>c<\/b>,<b>e<\/b>, The symbols are half-hourly FLUXNET2015 measurements for NEE (gold symbols) (<b>a<\/b>), daytime GPP (blue symbols) (<b>c<\/b>) and nighttime Re (magenta symbols) (<b>e<\/b>) for 86 sites across North America and Europe. The linear regression lines in <b>a<\/b>, <b>c<\/b> and <b>e<\/b> indicate fixed-effect relationships of fundamental constraints on ecosystem carbon fluxes according to the modified Arrhenius function (null models as in equation (<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"equation anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Equ1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>)). <b>b<\/b>,<b>d<\/b>,<b>f<\/b>, The box plots display the distribution of measured fluxes across bins of the modified Arrhenius function (axes labels and units in <b>b<\/b>, <b>d<\/b> and <b>f<\/b> are the same as in <b>a<\/b>, <b>c<\/b> and <b>e<\/b>, respectively) grouped by ALAN intensity to illustrate variation in carbon fluxes relative to energetic constraints as a function of ALAN. The boxes represent interquartile ranges (IQR), the horizontal lines denote medians, the whiskers extend to 1.5 \u00d7 IQR and the points indicate outliers.<\/p>\n<p>Backward selection and variance-weighting were applied to GAMMs fitted to half-hourly NEE, GPP and Re observations (<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"section anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Sec2\" rel=\"nofollow noopener\" target=\"_blank\">Methods<\/a>; Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a>) with the explanatory variable identified in the LMMs. In the final GAMMs, all Fc retained a significant interaction between ALAN and ND (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a> and Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a>). Notably, the NEE GAMM did not retain GS as a significant predictor, suggesting that the seasonality in instantaneous NEE responses was captured by GPP and Re, which both retained GS effects (Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a>). During GAMM selection, VPD (selected in the Re LMM) exhibited consistently high concurvity (&gt;0.8) with other smooth terms, including models in which ALAN was removed, indicating substantial collinearity with the modified Arrhenius function. DtNUP, selected in the GPP LMM, contributed no additional explanatory power in all GAMMs.<\/p>\n<p><b id=\"Fig3\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 3: Nonlinear influence of ALAN and ND on ecosystem metabolism.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41558-025-02481-0\/figures\/3\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig3\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/11\/41558_2025_2481_Fig3_HTML.png\" alt=\"figure 3\" loading=\"lazy\" width=\"685\" height=\"697\"\/><\/a><\/p>\n<p><b>a<\/b>\u2013<b>i<\/b>, GAMMs fitted to half-hourly carbon flux measurements consistently selected smooth tensor product interactions between ALAN and ND for NEE (<b>a<\/b>\u2013<b>c<\/b>), GPP (<b>d<\/b>\u2013<b>f<\/b>) and Re (<b>g<\/b>\u2013<b>i<\/b>). <b>a<\/b> (R2adj\u2009=\u20090.430; fREML\u2009=\u20091.35\u2009\u00d7\u2009107), <b>d<\/b> and <b>g<\/b> show observed versus predicted fluxes for the final variance-weighted GAMMs (Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a>), which account for heteroscedasticity across the range of observed fluxes (Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a> and Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig7\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>). <b>b<\/b>, <b>e<\/b> and <b>h<\/b> illustrate smooth estimates of the tensor product interaction across the gradient of ALAN intensity and ND (coloured lines, with shaded ribbons representing mean predictions\u2009\u00b1\u200995% confidence intervals). For GPP, <b>e<\/b>, and Re, <b>h<\/b>, predictions are shown separately for the GS and non-GS, whereas for NEE, <b>b<\/b>, the GS was not selected as a significant predictor. <b>c<\/b>, <b>f<\/b> and <b>i<\/b> depict GAMM-derived estimates of the relative change in each flux across gradients of ALAN intensity and ND, expressed relative to ALAN\u2009=\u20090, with shaded areas denoting 95% confidence intervals around the mean.<\/p>\n<p>The variance weighting substantially reduced residual heteroscedasticity across all Fc, with the scale estimate reduced by ~95% and adjusted R\u00b2 (R2adj) reduced by 0.06\u20130.11 in weighted compared with unweighted final GAMMs, indicating improved model stability through decreased overfitting to high-variance observations (Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a> and Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig7\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>). Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a>, right panels, shows weighted GAMM estimates of relative changes in each Fc across gradients of ALAN intensity and ND. Partial effect surfaces illustrating nonlinear ALAN\u2009\u00d7\u2009ND interactions at half-hourly timescales are presented in Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig8\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a>, along with residual diagnostics indicating no substantial autocorrelation after model fitting.<\/p>\n<p>LMMs and GAMMs fitted to mean daily NEE, GPP and Re yielded more consistent trends compared with models fitted to half-hourly observations. All daily LMMs and GAMMs identified GS and ND as significant predictors, with the GPP LMM selecting DtNUP and the Re LMM selecting ALAN as explanatory variables (Supplementary Tables <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">6<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">7<\/a>). All of the daily GAMMs selected the smooth tensor product between ALAN and ND (Supplementary Tables <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">8<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">9<\/a>). Compared with the half-hourly models, the daily GAMMs exhibited smoother and more monotonic relationships between ALAN and Fc, reflecting the reduction in diel and short-term variability through temporal aggregation (Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a>). Temporal aggregation led to clearer trends in predicted relative changes in Fc across gradients of ALAN intensity (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a>), in contrast to more variable patterns in the half-hourly GAMM predictions (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3c,f,i<\/a>). Notably, whereas ALAN consistently increased Re in half-hourly GAMMs and particularly during short nights (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3h,i<\/a>), the daily GAMMs showed a contrasting pattern, with Re increasing most with ALAN intensity during longer nights (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4c,f<\/a>). This divergence demonstrates how the aggregation of diel variability can modify the apparent direction and magnitude of ALAN effects on Fc. The partial effect surfaces from daily models showed more regular gradients and reduced nonlinear complexity, whereas residual autocorrelation was minimal, supporting the suitability of daily models for capturing net ALAN effects on ecosystem metabolism (Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a>).<\/p>\n<p><b id=\"Fig4\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 4: Nonlinear response of mean daily ecosystem carbon fluxes to ALAN and ND.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41558-025-02481-0\/figures\/4\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig4\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/11\/41558_2025_2481_Fig4_HTML.png\" alt=\"figure 4\" loading=\"lazy\" width=\"685\" height=\"396\"\/><\/a><\/p>\n<p><b>a<\/b>\u2013<b>c<\/b>, The box plots display the distribution of measured mean daily NEE (<b>a<\/b>), GPP (<b>b<\/b>) and Re (<b>c<\/b>) across ND groups (short ND: n\u2009=\u2009197,247). The boxes represent the interquartile ranges (IQR), the horizontal lines denote medians, the whiskers extend to 1.5\u00d7 the IQR and the points indicate outliers. <b>d<\/b>\u2013<b>f<\/b>, The variance-weighted GAMM predictions (Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">9<\/a>) for relative changes in daily mean NEE (<b>d<\/b>), GPP (<b>e<\/b>) and Re (<b>f<\/b>), expressed relative to ALAN\u2009=\u20090 for ND groups as in Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a>, with shaded ribbons representing mean predictions\u2009\u00b1\u200995% confidence intervals.<\/p>\n<p>The role of ALAN along with longer-term drivers of ecosystem metabolism was evaluated by constructing a piecewise structural equation model (SEM) integrating multiple exogenous predictors and hypothesized mediation pathways. The final SEM incorporated GS length, ALAN intensity and climatic variables including SW, VPD and T, along with the urban metric DtNUP (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5a<\/a>). The modified Arrhenius function was not selected, reflecting how annual temporal aggregation reduces positive and negative deviations in fundamental constraints compared with short-term flux variability. The aggregated measures of ND were also not selected, with phenological drivers such as GS length more important at annual timescales (Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">10<\/a>). The mediation analysis, using nonparametric bootstrap resampling to quantify both direct and indirect effects of GS length and indirect effects of ALAN on NEE, supports the inference that the influence of ALAN on ecosystem metabolism is primarily mediated through increased Re (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5b<\/a>). The influence of GS length on NEE was significantly mediated through increased GPP (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5b<\/a>). The leave-one-out sensitivity analysis of the SEM indicated that no alternative model performed better than the full model (Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">11<\/a>). Notably, the exclusion of ALAN, DtNUP, VPD or GS length led to significant declines in model performance, reflecting the importance of these predictors in explaining the interannual variation in ecosystem metabolism (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5c<\/a>).<\/p>\n<p><b id=\"Fig5\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 5: Final SEM structure for annual NEE, GPP and Re fluxes.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41558-025-02481-0\/figures\/5\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig5\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/11\/41558_2025_2481_Fig5_HTML.png\" alt=\"figure 5\" loading=\"lazy\" width=\"685\" height=\"459\"\/><\/a><\/p>\n<p><b>a<\/b>, The hypothesized pathways linking explanatory variables to ecosystem carbon fluxes show the standardized path coefficients of the final SEM with significance levels (****P\u2009P\u2009P\u2009P\u2009P values in Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">10<\/a>). The tests are two-sided, with no adjustments for multiple comparisons. The arrow thickness indicates the magnitude of standardized effect sizes, the black arrows and text indicate direct pathways, the double-headed grey arrows and text indicate the residual correlations and the blue arrows and text indicate the mediation pathways supported by the bootstrap analysis. The SEM was fitted to complete cases for all variables (605 site years, 84 sites). <b>b<\/b>, The bootstrap-derived estimates shown are means and 95% percentiles from 1,000 replicates for the direct and indirect effects of GS length and ALAN on NEE. <b>c<\/b>, The outputs from a leave-one-out analysis show the change in marginal (lighter-coloured symbols and lines) and conditional (darker-coloured symbols and lines) R\u00b2 (\u0394R\u00b2) for NEE (gold), GPP (blue) and Re (magenta) relative to the full model after systematically removing each exogenous predictor (Supplementary Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">11<\/a>).<\/p>\n<p>To ensure our data analysis was robust to site bias across ALAN intensities (17, 22 and 47 sites at high, medium and low ALAN intensities, respectively, and 34 sites in North America and 52 sites in Europe), we repeated all GAMM and SEM analyses using a balanced dataset with an equal representation of low, medium and high ALAN intensity sites per continent (Extended Data Figs. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig11\" rel=\"nofollow noopener\" target=\"_blank\">6<\/a>\u2013<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig14\" rel=\"nofollow noopener\" target=\"_blank\">9<\/a>). The models fitted to the balanced dataset showed consistently significant nonlinear interactions between ALAN and ND across temporal scales (Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig11\" rel=\"nofollow noopener\" target=\"_blank\">6<\/a>), and the annual SEM retained the core structure of ALAN indirectly influencing NEE through increased Re (Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig14\" rel=\"nofollow noopener\" target=\"_blank\">9<\/a>). Whereas several weaker interactions (for example Re\u2009~\u2009T and NEE\u2009~\u2009GS length) were no longer significant owing to reduced sample size, the SEM retained dominant pathways, and the overall explanatory power was comparable (R2m\u2009=\u20090.64, R2c\u2009=\u20090.70 for NEE). Notably, the standardized coefficients strengthened between ALAN\u2009~\u2009Re and Re\u2009~\u2009NEE when the SEM was fitted to the balanced dataset. Our observed ALAN effects on ecosystem metabolism are therefore robust to spatial imbalances in ALAN intensity across FLUXNET2015 site distribution.<\/p>\n<p>Our study provides cross-continental evidence of ALAN\u2019s influence on ecosystem metabolism across timescales. We demonstrate that ALAN consistently modifies the relationship between Fc and their fundamental energetic constraints (Figs. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>\u2013<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a>). The Re response to fundamental constraints was particularly sensitive to ALAN intensity at short (half-hourly and daily) timescales (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a> and Supplementary Tables <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">6<\/a>). Alongside Re, GPP and NEE exhibited significant nonlinear interactions between ND and ALAN intensity, revealing the importance of ALAN magnitude and timing in modulating ecosystem metabolism across scales (Figs. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a>). At annual timescales, the influence of ALAN on NEE was primarily mediated through increased Re rather than the direct suppression of GPP (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a>). Taken together, our findings demonstrate the role of ALAN as a pervasive stressor capable of disrupting carbon balance across spatial and temporal scales.<\/p>\n<p>The nonlinear influence of ALAN on ecosystem metabolism was strongly modulated by diel cycles and seasonality, demonstrating the importance of phenological dynamics<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 34\" title=\"Wang, L. et al. Artificial light at night outweighs temperature in lengthening urban growing seasons. Nat. Cities 2, 506&#x2013;517 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR34\" id=\"ref-link-section-d68418405e1501\" rel=\"nofollow noopener\" target=\"_blank\">34<\/a> and biogeochemical feedbacks in shaping long-term carbon balance<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 35\" title=\"Davidson, E. A. &amp; Janssens, I. A. Temperature sensitivity of soil carbon decomposition and feedbacks to climate change. Nature 440, 165&#x2013;173 (2006).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR35\" id=\"ref-link-section-d68418405e1505\" rel=\"nofollow noopener\" target=\"_blank\">35<\/a>. The temporal aggregation led to notable shifts in the strength and direction of ALAN effects on Re, whereas GPP and NEE displayed more consistent nonlinear responses to ND across timescales (Figs. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a>). At the half-hourly resolution, short nights showed the strongest ALAN-induced increases in Re (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3h,i<\/a>), reflecting immediate physiological and microbial responses such as prolonged stomatal opening<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 36\" title=\"Matzke, E. B. The effect of street lights in delaying leaf-fall in certain trees. Am. J. Bot. 23, 446&#x2013;452 (1936).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR36\" id=\"ref-link-section-d68418405e1527\" rel=\"nofollow noopener\" target=\"_blank\">36<\/a>, sustained leaf dark respiration<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 37\" title=\"de Dios, V. R. et al. Processes driving nocturnal transpiration and implications for estimating land evapotranspiration. Sci. Rep. 5, 10975 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR37\" id=\"ref-link-section-d68418405e1531\" rel=\"nofollow noopener\" target=\"_blank\">37<\/a> and elevated microbial decomposition under disrupted circadian regulation<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 38\" title=\"H&#xF6;lker, F., Wolter, C., Perkin, E. K. &amp; Tockner, K. Light pollution as a biodiversity threat. Trends Ecol. Evol. 25, 681&#x2013;682 (2010).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR38\" id=\"ref-link-section-d68418405e1535\" rel=\"nofollow noopener\" target=\"_blank\">38<\/a>. By contrast, daily mean nighttime Re estimates indicated larger ALAN-related increases during longer nights (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4f<\/a>), demonstrating how aggregation dampens short-term variability while revealing broader shifts in Re across longer nights. GPP exhibited consistent positive or nonlinear ALAN effects across timescales (Figs. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a>), probably driven by nocturnal illumination extending photosynthetic activity at medium ALAN intensities<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 39\" title=\"Meng, L. et al. Artificial light at night: an underappreciated effect on phenology of deciduous woody plants. PNAS Nexus 1, pgac046 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR39\" id=\"ref-link-section-d68418405e1558\" rel=\"nofollow noopener\" target=\"_blank\">39<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 40\" title=\"Lo Piccolo, E. et al. Shedding light on the effects of LED streetlamps on trees in urban areas: Friends or foes?. Sci. Total Environ. 865, 161200 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR40\" id=\"ref-link-section-d68418405e1561\" rel=\"nofollow noopener\" target=\"_blank\">40<\/a>. Temporal scale and ND thus collectively shape ALAN\u2019s ecological impact, whereas diel averaging can obscure short-lived physiological responses while reflecting cumulative nighttime effects.<\/p>\n<p>Re exhibited greater sensitivity to ALAN than GPP across timescales (Figs. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a> and Supplementary Tables <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>\u2013<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">11<\/a>), and the SEM confirmed that ALAN primarily influences NEE indirectly via increased Re at annual timescales (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a>). The destabilizing effect of ALAN on production-respiration coupling will arise from shifts in multiple autotrophic and heterotrophic processes controlling carbon allocation and use efficiency<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 17\" title=\"Gaston, K. J., Visser, M. E. &amp; H&#xF6;lker, F. The biological impacts of artificial light at night: the research challenge. Philos. Trans. R. Soc. B 370, 20140133 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR17\" id=\"ref-link-section-d68418405e1591\" rel=\"nofollow noopener\" target=\"_blank\">17<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 38\" title=\"H&#xF6;lker, F., Wolter, C., Perkin, E. K. &amp; Tockner, K. Light pollution as a biodiversity threat. Trends Ecol. Evol. 25, 681&#x2013;682 (2010).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR38\" id=\"ref-link-section-d68418405e1594\" rel=\"nofollow noopener\" target=\"_blank\">38<\/a>. The greater Re sensitivity may reflect a higher capacity of autotrophs to acclimate to ALAN through conservative growth strategies such as increased shoot-to-root ratios<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 20\" title=\"Bennie, J., Davies, T. W., Cruse, D. &amp; Gaston, K. J. Ecological effects of artificial light at night on wild plants. J. Ecol. 104, 611&#x2013;620 (2016).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR20\" id=\"ref-link-section-d68418405e1602\" rel=\"nofollow noopener\" target=\"_blank\">20<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 41\" title=\"Qi, Y., Wei, W., Chen, C. &amp; Chen, L. Plant root-shoot biomass allocation over diverse biomes: a global synthesis. Glob. Ecol. Conserv. 18, e00606 (2019).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR41\" id=\"ref-link-section-d68418405e1605\" rel=\"nofollow noopener\" target=\"_blank\">41<\/a>. In ecosystems dominated by C3 plants, for instance, prolonged ALAN exposure can disrupt circadian regulation and prolong stomatal opening, reducing carbon uptake efficiency, increasing mortality and senescence, and leading to reduced GPP over time<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 42\" title=\"Didaran, F. et al. The mechanisms of photoinhibition and repair in plants under high light conditions and interplay with abiotic stressors. J. Photochem. Photobiol. B 259, 113004 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR42\" id=\"ref-link-section-d68418405e1612\" rel=\"nofollow noopener\" target=\"_blank\">42<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 43\" title=\"Anic, V., Gaston, K. J., Davies, T. W. &amp; Bennie, J. Long-term effects of artificial nighttime lighting and trophic complexity on plant biomass and foliar carbon and nitrogen in a grassland community. Ecol. Evol. 12, e9157 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR43\" id=\"ref-link-section-d68418405e1615\" rel=\"nofollow noopener\" target=\"_blank\">43<\/a>. Such trophic mismatches and shifts in carbon allocation are likely to accumulate across levels of biological organization, space and time<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 44\" title=\"Johnston, A. S. A. Predicting emergent animal biodiversity patterns across multiple scales. Glob. Change Biol. 30, e17397 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR44\" id=\"ref-link-section-d68418405e1619\" rel=\"nofollow noopener\" target=\"_blank\">44<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 45\" title=\"Sanders, D. et al. How artificial light at night may rewire ecological networks: concepts and models. Philos. Trans. R. Soc. B 378, 20220368 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR45\" id=\"ref-link-section-d68418405e1622\" rel=\"nofollow noopener\" target=\"_blank\">45<\/a>, leading to progressive declines in NEE in illuminated ecosystems.<\/p>\n<p>The ecological impacts of ALAN have primarily been examined at local scales<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 6\" title=\"Sanders, D., Frago, E., Kehoe, R., Patterson, C. &amp; Gaston, K. J. A meta-analysis of biological impacts of artificial light at night. Nat. Ecol. Evol. 5, 74&#x2013;81 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR6\" id=\"ref-link-section-d68418405e1629\" rel=\"nofollow noopener\" target=\"_blank\">6<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 17\" title=\"Gaston, K. J., Visser, M. E. &amp; H&#xF6;lker, F. The biological impacts of artificial light at night: the research challenge. Philos. Trans. R. Soc. B 370, 20140133 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR17\" id=\"ref-link-section-d68418405e1632\" rel=\"nofollow noopener\" target=\"_blank\">17<\/a>, but landscape-scale factors will confound or amplify these localized effects<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 2\" title=\"Linares Arroyo, H. et al. Monitoring, trends and impacts of light pollution. Nat. Rev. Earth Environ. 5, 417&#x2013;430 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR2\" id=\"ref-link-section-d68418405e1636\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>. Urban proximity influenced GPP in our analysis, whereas ALAN directly influenced Re (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a>), suggesting distinct pathways through which nighttime lighting and urban characteristics modify ecosystem metabolism. Balancing sites across low, medium and high ALAN intensities further indicates potentially stronger mediating effects of ALAN on NEE via Re (Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig14\" rel=\"nofollow noopener\" target=\"_blank\">9<\/a>). Despite the pervasive nature of light pollution, ALAN remains overlooked in ESM carbon\u2013climate projections that otherwise account for climate and land use changes. Current observational data, however, do not enable the disentangling of the contribution of ALAN relative to sunlight in shaping Fc, and future targeted experimental studies will be needed to resolve these relationships.<\/p>\n<p>Global eddy covariance networks such as FLUXNET are vital for monitoring ecosystem metabolism across diverse climates and land use types, but they are typically biased towards temperate regions, seminatural landscapes and dark skies (Extended Data Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#Fig6\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>). Urban flux towers are particularly scarce, and although networks such as Urban PLUMBER have been established, they do not measure Fc (ref. <a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 46\" title=\"Lipson, M. et al. Harmonized gap-filled datasets from 20 urban flux tower sites. Earth Syst. Sci. Data 14, 5157&#x2013;5178 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR46\" id=\"ref-link-section-d68418405e1669\" rel=\"nofollow noopener\" target=\"_blank\">46<\/a>). Similarly, available nighttime light satellite products used here (Visible Infrared Imaging Radiometer Suite (VIIRS) and Defence Meteorological Satellite Programme (DMSP)) are coarse in spatial resolution, are insensitive to blue light emitted by white light-emitting diode (LED) lighting<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 47\" title=\"Miller, S. D. et al. Upper atmospheric gravity wave details revealed in nightglow satellite imagery. Proc. Natl Acad. Sci. USA 112, E6728&#x2013;E6735 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR47\" id=\"ref-link-section-d68418405e1673\" rel=\"nofollow noopener\" target=\"_blank\">47<\/a> and cannot fully capture local heterogeneity in ALAN exposure at flux tower sites.<\/p>\n<p>Enhanced satellite sensors with improved spectral and spatial resolution would advance ALAN monitoring<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 2\" title=\"Linares Arroyo, H. et al. Monitoring, trends and impacts of light pollution. Nat. Rev. Earth Environ. 5, 417&#x2013;430 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR2\" id=\"ref-link-section-d68418405e1681\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>, but ground-based measurements are also needed to capture how cloud cover exacerbates or reduces skyglow (brightening of the night sky) in high or low ALAN intensity areas, respectively<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 48\" title=\"Kyba, C. C. M., Ruhtz, T., Fischer, J. &amp; H&#xF6;lker, F. Cloud coverage acts as an amplifier for ecological light pollution in urban ecosystems. PLoS ONE 6, e17307 (2011).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR48\" id=\"ref-link-section-d68418405e1685\" rel=\"nofollow noopener\" target=\"_blank\">48<\/a>. The coordinated expansion of eddy covariance flux tower networks along with complementary measurements, such as chamber-based respiration estimates and isotopic tracers, will be critical to disentangle the mechanisms by which ALAN alters ecosystem metabolism. Expanding ecosystem-level Fc measurements into urbanized, tropical, arid and high-latitude regions is vital to evaluate the global relevance of ALAN impacts on carbon cycling. While monitoring is essential, mitigation is also readily achievable.<\/p>\n<p>Artificial light is ubiquitous and often beneficial, but the negative ecological effects of light pollution can be reduced while balancing societal benefits. Retrofitting LED lighting can reduce light pollution<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 5\" title=\"J&#xE4;gerbrand, A. K. &amp; Spoelstra, K. Effects of anthropogenic light on species and ecosystems. Science 380, 1125&#x2013;1130 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR5\" id=\"ref-link-section-d68418405e1696\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a>, but it often results in over-illumination due to their higher efficiency<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 49\" title=\"&#x15A;ci&#x119;&#x17C;or, T. Effect of street lighting on the urban and rural night-time radiance and the brightness of the night sky. Remote Sens. 13, 1654 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR49\" id=\"ref-link-section-d68418405e1700\" rel=\"nofollow noopener\" target=\"_blank\">49<\/a>. Given that lighting accounts for 20% of global electricity consumption and 6% of CO2 emissions<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 50\" title=\"UN Environment Programme. The Rapid Transition to Energy Efficient Lighting: An Integrated Policy Approach (United Nations Environment Programme, 2013); &#010;                https:\/\/www.unep.org\/resources\/report\/rapid-transition-energy-efficient-lighting-integrated-policy-approach&#010;                &#010;              \" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR50\" id=\"ref-link-section-d68418405e1706\" rel=\"nofollow noopener\" target=\"_blank\">50<\/a> and can exacerbate degraded air quality<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 51\" title=\"Kocifaj, M. &amp; Barentine, J. C. Air pollution mitigation can reduce the brightness of the night sky in and near cities. Sci. Rep. 11, 14622 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR51\" id=\"ref-link-section-d68418405e1710\" rel=\"nofollow noopener\" target=\"_blank\">51<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 52\" title=\"Stark, H. et al. City lights and urban air. Nat. Geosci. 4, 730&#x2013;731 (2011).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR52\" id=\"ref-link-section-d68418405e1713\" rel=\"nofollow noopener\" target=\"_blank\">52<\/a>, mitigation interventions such as directional, dimmable and adaptive lighting designs<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 2\" title=\"Linares Arroyo, H. et al. Monitoring, trends and impacts of light pollution. Nat. Rev. Earth Environ. 5, 417&#x2013;430 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR2\" id=\"ref-link-section-d68418405e1718\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a> offer wider cobenefits. Unlike climate and land use change, the effects of light pollution could be mitigated overnight<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 53\" title=\"Smith, M. Time to turn off the lights. Nature 457, 27&#x2013;27 (2009).\" href=\"http:\/\/www.nature.com\/articles\/s41558-025-02481-0#ref-CR53\" id=\"ref-link-section-d68418405e1722\" rel=\"nofollow noopener\" target=\"_blank\">53<\/a>. Our study demonstrates the pervasive influence of light pollution on ecosystem metabolism across scales and highlights the urgent need to integrate ALAN into global change research, assessments of carbon\u2013climate feedbacks and mitigation strategies. Developing a higher resolution understanding of species, community and ecosystem sensitivity to ALAN will be central to designing interventions that both safeguard biodiversity and preserve the land carbon sink.<\/p>\n","protected":false},"excerpt":{"rendered":"Artificial light pollution is accelerating across the globe1,2 and has widespread consequences for people3,4 and the planet5,6,7. Shifts&hellip;\n","protected":false},"author":2,"featured_media":177491,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[269],"tags":[26594,442,6134,100652,18,440,29959,910,19,17,133],"class_list":{"0":"post-177490","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-biogeochemistry","9":"tag-climate-change","10":"tag-climate-change-climate-change-impacts","11":"tag-ecophysiology","12":"tag-eire","13":"tag-environment","14":"tag-environmental-law-policy-ecojustice","15":"tag-general","16":"tag-ie","17":"tag-ireland","18":"tag-science"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115539412860879959","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/177490","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=177490"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/177490\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/177491"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=177490"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=177490"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=177490"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}