Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Do urban fish exhibit impaired sleep? Light pollution suppresses melatonin production in European perch

03.04.2020

Melatonin controls the body clock – high melatonin levels make us feel tired in the evening. However, the hormone also plays an important role in animals’ biological rhythms. Artificial light at night – light pollution – can suppress the production of melatonin in fish, even at very low light intensities, a finding established by researchers from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB).

Melatonin regulates the day-night rhythm in humans and vertebrates. Organs, tissue and cells set their internal clock depending on the level of this hormone. As a result, melatonin also controls processes such as reproduction and growth.


The European perch is sensitive to light pollution.

Michael Feierabend

Hinweis zur Verwendung von Bildmaterial: Die Verwendung des Bildmaterials zur Pressemitteilung ist bei Nennung der Quelle vergütungsfrei gestattet. Das Bildmaterial darf nur in Zusammenhang mit dem Inhalt dieser Pressemitteilung verwendet werden.

Vertebrates and humans detect differences in ambient brightness via photoreceptors, e.g. on the retina of the eye. Bright light perceived by these receptors suppresses the production of melatonin, while the hormone level is elevated during the dark phase. Artificial light at night may disturb melatonin levels.

The team of IGB researchers investigated melatonin production in European perch. During the day, all fish were exposed to daylight. At night, lighting varied depending on the group: the control group spent the night in complete darkness, whereas the other three groups were exposed to light intensities at 0.01, 0.1 and 1 lux.

After ten days, the scientists measured melatonin levels at three-hour intervals over a period of 24 hours. The result: even the lowest light intensity of 0.01 lux was enough to suppress melatonin production; higher light intensities led to an increasingly strong gradual reduction of melatonin.

For comparison, illumination intensities to which organisms are exposed at night: on a crystal clear night, illumination intensity is less than 0.001 lux. On a full moon night, it measures a maximum of 0.3 lux. Sky glow over a city can reach illumination intensities of up to 1 lux and more, and street can lighting anything up to 150 lux.

Even nighttime urban sky glow suppresses melatonin formation:

“The astonishing thing is that the intensities of urban sky glow are enough to suppress melatonin production in fish,” stated lead author Franziska Kupprat from IGB. Large areas throughout the world are affected by this kind of light pollution.

This is because light emitted by lighting installations radiates into the sky, and reflects off clouds and particles, creating significant sky glow that extends further than the actual light radius of the light source.

Light intensity had no impact on the rhythm of melatonin production. All specimens experienced an increase in melatonin formation during the course of the afternoon, peaking at night.

“Previous studies have shown that higher intensities of night light, such as 10 and 100 lux, also affect the melatonin rhythm in perch. This is because the melatonin produced at night had declined to such an extent that it no longer differed to low values measured during the day,“ explained IGB’s Dr. Franz Hölker.

Fish spend much of their lives asleep, although this is not apparent because they have no eyelids. Like with all living things, fish need sleep to regenerate. IGB’s Professor Werner Kloas, leader of the study, explained the effects of disturbed melatonin levels: “Our previous research methods do not enable us to assess whether urban fish experience a lack of sleep due to light pollution.

However, we assume this is the case because melatonin is an important factor influencing sleep in vertebrates, including fish. One thing for sure is that other body functions such as immune defence, growth and reproduction can be disturbed by altered melatonin production.“

Wissenschaftliche Ansprechpartner:

Franziska Kupprat
Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB)
Doctoral student
Department Ecophysiology and Aquaculture
Email: kupprat@igb-berlin.de

PD Dr. Franz Hölker
Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB)
Reasearch group leader: Light pollution and ecophysiology
Department Ecohydrology
Email: hoelker@igb-berlin.de

Originalpublikation:

Franziska Kupprat, Franz Hölker, Werner Kloas (2020). Can skyglow reduce nocturnal melatonin concentrations in Eurasian perch? Environmental Pollution, Volume 262 https://doi.org/10.1016/j.envpol.2020.114324

Nadja Neumann | idw - Informationsdienst Wissenschaft
Further information:
https://www.igb-berlin.de

More articles from Life Sciences:

nachricht Turning carbon dioxide into liquid fuel
06.08.2020 | DOE/Argonne National Laboratory

nachricht Tellurium makes the difference
06.08.2020 | Friedrich-Schiller-Universität Jena

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: ScanCut project completed: laser cutting enables more intricate plug connector designs

Scientists at the Fraunhofer Institute for Laser Technology ILT have come up with a striking new addition to contact stamping technologies in the ERDF research project ScanCut. In collaboration with industry partners from North Rhine-Westphalia, the Aachen-based team of researchers developed a hybrid manufacturing process for the laser cutting of thin-walled metal strips. This new process makes it possible to fabricate even the tiniest details of contact parts in an eco-friendly, high-precision and efficient manner.

Plug connectors are tiny and, at first glance, unremarkable – yet modern vehicles would be unable to function without them. Several thousand plug connectors...

Im Focus: New Strategy Against Osteoporosis

An international research team has found a new approach that may be able to reduce bone loss in osteoporosis and maintain bone health.

Osteoporosis is the most common age-related bone disease which affects hundreds of millions of individuals worldwide. It is estimated that one in three women...

Im Focus: AI & single-cell genomics

New software predicts cell fate

Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

Rare Earth Elements in Norwegian Fjords?

06.08.2020 | Earth Sciences

Anode material for safe batteries with a long cycle life

06.08.2020 | Power and Electrical Engineering

Turning carbon dioxide into liquid fuel

06.08.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>