Light & Life Below the Waterline: An Arctic Focus

2021-07-02

 |  Science & The Environment

The Arctic Ocean is made up of a delicate and diverse ecosystem of marine life. Climate change has had widespread effects on this ecosystem, including well-known impacts such as thinning sea ice, species extinction, and increasing temperature of permafrost. However, one lesser known consequence of climate change in the Arctic is widespread exposure to light. Changing light patterns have the potential to alter patterns in marine arctic food chains, and can even affect the humans that call this region home.

Both natural and artificial light levels are changing in the Arctic Ocean. Recently, this region has experienced higher temperatures and fewer extreme cold events, leading to melting ice. Thinner ice allows more natural light to enter marine ecosystems through increased transparency and gaps. At the same time, the amount of artificial light has also increased, as thinning ice has created more open passages in the Arctic Ocean. As the number of open passages increases, the scientific, fisheries, and tourism sectors have encouraged human presence in the Arctic, and their associated equipment emits light that would not naturally occur in the area.

Increased natural light is impacting marine arctic ecosystems from the bottom up. For example, although most kelp species in the Arctic (e.g., Laminaria solidungula) are used to rapid growth seasons, certain regions of the Arctic Ocean are now exposed to light for much longer periods of time. With increased sunlight, kelp species are able to grow faster and for longer intervals, allowing them to occupy more space in the Arctic Ocean. These changes in kelp growth can impact other species, higher up the food chain, by altering available food and habitat. 

Artificial light is also impacting marine organisms in the Arctic. This man-made light works by disrupting the natural cues that help many species navigate and move to other areas. Some light-sensitive species that inhabit the Arctic Ocean, include zooplankton (e.g., Calanus hyperboreus, C. glacialis, and C. finmarchicus), which rely on natural light sources, such as the moon, stars, and aurora borealis, to feed and mate. Research has shown that working-light from ships can disturb the behaviour of these zooplankton down to at least 200 metres below sea level. On the other hand, further up the food chain, researchers have discovered potential positive effects of this additional light entering the water. For example, more light allows some fish species, such as Atlantic Cod and Salmon, to see their prey better, and thus hunt more effectively. Overall, increased exposure to light can have positive and negative effects, depending on the species and its position in the food chain. 

The effects of this influx of light extend beyond marine Arctic species. Around four million people live and work in the Arctic, including Indigenous groups and scientists. Marine wildlife supports the livelihoods of many local community members, and the influx of natural and artificial light ultimately influences the lives of Arctic species and residents alike. As one example, a team of scientists from Norway, the US, and the UK are studying the impacts of artificial light on Arctic zooplankton and fish. They found that artificial light of any kind affects the behaviour of Arctic species, meaning that scientists can’t collect data on these organisms without impacting their own results. This calls much of the existing Arctic research into question and presents a challenge for future data collection in the Arctic Ocean. 

Changes in the behaviour of marine organisms also create challenges for Indigenous groups. Remote locations and transportation costs can create food insecurity in many Arctic regions. For Indigenous groups, fishing plays an important role in preventing this food insecurity, while also preserving cultural identity. For example, sharing food and knowledge can help local economies, and many local foods, such as fish, are accessible and high in nutritional value. This once-reliable food source has become erratic as fish behaviour has been altered by light. 

It is clear that light strongly impacts marine life in the Arctic as well as the people who rely on this ecosystem. Luckily, there are already some efforts in place to address this issue. For instance, there is currently a ban on commercial fishing in most areas of the Arctic Ocean to promote more sustainable fishing practices and minimize human impact from fishing. Despite attempts to preserve Arctic life, the issue of increased light is still not widely understood. To make matters worse, data concerning the Arctic Ocean is limited in general, and may even be inaccurate due to human interference. Many environmental organizations have embraced the need to organize and share knowledge about the Arctic by creating databases that include a variety of different perspectives and resources. Links to some of these databases, and other useful information, are included below if you’d like to learn more about Arctic life.

  • This comprehensive list of digital petitions has been compiled by the World Wildlife Fund to provide opportunities for activists of all ages to take action on this issue and others.
  • ArcNet is an Arctic Ocean Network of Priority Areas for Conservation, backed by the world’s most comprehensive database on Arctic biodiversity. This database brings together a wide variety of knowledge from different perspectives, including marine biologists, Indigenous peoples, local communities, and governments.
  • The Arctic Kelp Project is attempting to catalogue different species of Arctic kelp, and determine how their growth patterns will be affected by global warming. 
  • This collection of climate justice terms and issues relating to the rights of Arctic Indigenous Peoples was compiled by the Georgetown Journal of International Affairs.