Artificial night sky poses serious threat to coastal species

Date:
June 22, 2020
Source:
University of Plymouth
Summary:
A study shows the presence of artificial light originating from
cities several kilometers away (also known as artificial skyglow)
disrupts the lunar compass species use when covering long distances.



FULL STORY ==========================================================================
The artificial lighting which lines the world's coastlines could be
having a significant impact on species that rely on the moon and stars
to find food, new research suggests.


========================================================================== Creatures such as the sand hopper (Talitrus saltator) orientate their
nightly migrations based on the moon's position and brightness of the
natural night sky.

However, a study by Bangor University and the University of Plymouth
shows the presence of artificial light originating from cities several kilometres away (also known as artificial skyglow) disrupts the lunar
compass they use when covering long distances.

In some cases, this can lead to them travelling towards the sea and away
from food, while in others it reduces the chance of them venturing out
on forays for food at all.

Writing in Current Biology, researchers say this could pose a distinct
threat not just to the health of sand hopper populations but also the
wider ecosystem, since they play an important role in breaking down and recycling algae washed up on strandlines.

The study was conducted as part of the Artificial Light Impacts on
Coastal Ecosystems (ALICE) project, funded by the Natural Environment
Research Council.



==========================================================================
Dr Thomas Davies, Lecturer in Marine Conservation at the University of
Plymouth (UK), is the paper's senior author and principal investigator
on the ALICE project. He said: "Skyglow is the most geographically
widespread form of light pollution. Surveys have shown it can currently
be detected above 23% of the world's coasts nightly, and with coastal
human populations set to at least double by 2060 its effects are only
going to increase. Our results show it is already having demonstrable
impacts on biological processes that are guided by celestial light cues.

"Through the ALICE project, we are finding increasing evidence that light pollution from coastal cities can influence marine species inhabiting
nearby beaches, rocky shores and even the seafloor. These results
highlight how pervasive city lighting could be in shaping the ecology
of coastlines kilometres distant from their nearest urban centres. They
also highlight the potential for artificial skyglow to impact other
species that undergo migrations using the moon as a compass.

"While our understanding of the impacts of street lights on nature
has improved dramatically, artificial skyglow has been largely
overlooked. More work is urgently needed to fully understand the extent to which it is shaping the natural environment." Stuart Jenkins, Professor
of Marine Ecology at Bangor University and one of the study's co-authors, added: "It is easy to forget the critical influence of the moon in guiding
many organisms' movements. However, we are increasingly realising that by disrupting patterns of night time lighting, we are potentially reducing
the ability of animals to navigate. This new research on the shores of
North Wales shows clearly that very low levels of artificial light can
have far-reaching effects on coastal marine species." The sand hopper
is a common feature of Europe's coasts and spends daytimes buried in
the sand at depths of 10-30cm, emerging at night to feed on decaying
seaweed and other detritus.

For this study, researchers monitored the sand hopper population on Cable
Bay beach in North Wales (UK), a naturally dark location, over 19 nights between June and September 2019.

They observed the behaviour of almost 1,000 individuals under a range
of moon phases and weather conditions, before introducing artificial
light that replicated the intensity and colour of skyglow from towns
and cities around the UK coastline.


========================================================================== Story Source: Materials provided by University_of_Plymouth. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Daniela Torres, Svenja Tidau, Stuart Jenkins, Thomas
Davies. Artificial
skyglow disrupts celestial migration at night. Current Biology,
2020; 30 (12): R696 DOI: 10.1016/j.cub.2020.05.002 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200622133004.htm

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