High mercury levels found in Svalbard birds
Norwegian seabirds are struggling. Svalbard seabirds have mercury levels above the threshold for deleterious effects on reproduction, researchers have found.
The arrows for Norwegian seabird populations are pointing downwards.
Researchers have now recorded mercury levels above the threshold for effects in seabirds that live on Svalbard.
“We don’t know what effect this has on the population level, but we know that mercury affects reproduction, behaviour and survival,” says Silje Lundgren, from NTNU’s Department of Biology.
Mercury is toxic to both humans and animals even in small concentrations. It affects the hormonal and immune systems and can cause damage to the nervous system.
Struggling to survive
Lundgren studied the occurrence of a number of heavy metals and environmental toxins in Svalbard birds as part of her master’s thesis at NTNU, supervised by Professor Veerle Jaspers. In July 2017, she took samples of feathers from adult black-legged kittiwakes and Brünnich’s guillemots in Kongsfjorden on Svalbard, as well as samples of blood plasma from the kittiwakes.
The results, which have been published in the scientific journal Science of the Total Environment, showed high levels of mercury in both bird species, with the level in the kittiwakes exceeding the threshold for potential reproductive effects
Black-legged kittiwakes differ from other seabirds in that they do not dive, but obtain food from the surface. Photo: Geir Wing Gabrielsen/Norwegian Polar Institute
In the kittiwakes, the level of mercury was higher than what has been found previously in studies of seabirds in the Arctic.
“High concentrations of mercury will not necessarily have a negative impact on the individual level. But seabirds in general are struggling with survival and reproduction, and mercury can then be a factor contributing to population decline, along with other things,” Lundgren said.
Mercury facts
Mercury is a heavy metal that exists in different chemical forms. The most toxic is organic mercury, also known as methylmercury.
Mercury occurs in nature and can come from sources such as volcanic eruptions or gasification. Human activity such as mining and industry also leads to mercury emissions.
Methylmercury is transferred from mother to foetus during pregnancy, and in large quantities can lead to malformations in the child. It also affects the mental development of both foetuses and infants, and can lead to impaired learning ability and damage to motor skills.
Fish and other seafood, especially lean fish, are the main source of mercury in our diet today.
Source: Norwegian Institute for Marine Research
Climate change and avian influenza
Researcher Geir Wing Gabrielsen from the Norwegian Polar Institute has followed Norwegian seabird populations with argus eyes for several decades. He agrees with Lundgren that high mercury levels can be one of several unfortunate factors for the seabirds.
“Seabird populations are declining faster than other bird populations. On the Norwegian mainland, there has been a drastic decline in a number of seabird species in recent years,” Gabrielsen said.
Norway’s national monitoring program (SEAPOP) follows 35 species of seabirds. Of these, 13 species have been reduced by more than 50 per cent in the last 20 years.
Black-legged kittiwakes differ from other seabirds in that they don’t dive, but obtain nourishment from the surface. Photo: Geir Wing Gabrielsen/ Norwegian Polar Institute
Climate change, pollution, loss of breeding areas, hunting and diseases (including avian influenza) are to blame.
In the Arctic, where the temperature increase due to global warming has been the highest in the world, land ice is now melting. This means that metals and environmental pollutants stored in snow and ice are released and enter the food chain.
“The lion’s share of the pollution in the Arctic comes from Asia, where they have a high consumption of coal, including in industrial production. When air masses blowing north meet northern winds, the pollution is deposited in snow and ice,” Gabrielsen said.
Changes in food availability and diet
In Svalbard, 57 percent of the land area is covered by glaciers, and over 900 km of the coastline has glaciers that break off, “calving”, into the sea. In total, this means that 45 billion tons of meltwater mixed with sediments flows into the coastal waters every year.
The land-based sea ice in Svalbard fjords is disappearing. At the same time, climate change is causing warm, Atlantic water to flow northward, bringing with it animals and other organisms from lower latitudes.
Seabirds such as the kittiwake and the Brünnich’s guillemot, which previously lived on polar cod, have switched to eating Atlantic fish species, such as herring, capelin and krill.
This has had a positive effect on some seabird species in Svalbard. Food access has been good. At the same time, researchers are finding a connection between what the birds eat and their mercury levels.
Melting glaciers release pollutants
Researchers at the Polar Institute have seen how mercury levels in the kittiwakes on Svalbard increased after the birds changed their diet from Arctic to Atlantic fish species.
“This was primarily linked to an increase in the temperature in the surroundings and in the ocean,” says Gabrielsen.
Svalbard is now warming twice as fast as the rest of the Arctic, and five times faster than the global average.
“When the glaciers melt, the pollution stored in the glaciers will be released and flow into the sea. The mercury is taken up by nutrient organisms in the fjord. This causes the kittiwakes feeding in the fjord to have increased mercury levels,” says Gabrielsen.
Coal and industry in Asia
According to AMAP (the Arctic Monitoring and Assessment Programme), Asian countries accounted for half of the world’s mercury emissions to the atmosphere in 2015. Much of this is due to the use of coal as an energy source. The researchers believe that it is urgent to get Asian countries like China to reduce their emissions.
“Today, industry produces 250,000 different environmental pollutants that are released into the natural environment via the atmosphere, rivers and ocean currents. The chemical industry is the fastest growing in the world, “Gabrielsen says.
The NTNU researchers have an ongoing project with NINA, the Norwegian Institute for Nature Research, on the Interactive effects of pollutants and climate on seabirds in Arctic Coastal ecosystems (ClimACTox).
“Mercury is also one of the priority pollutants under investigation in that project, meaning we will follow up on the levels in different seabirds along with their population trajectories in Norway and on Svalbard,” Jaspers said.
The population data will be drawn from SEAPOP.
Reference:
Silje S. Lundgren, Naeem A. Abbasi, Courtney A. Waugh, Megan M. Lee, Tomasz M. Ciesielski, Geir W. Gabrielsen, Sébastien Descamps, Veerle L.B. Jaspers. Metals and other trace elements in plasma and feathers of seabirds breeding in Svalbard, Science of The Total Environment, Vol. 952, 2024, 175895, ISSN 0048-9697, https://doi.org/10.1016/j.scitotenv.2024.175895.
