While global pollution is a serious issue for most of the researchers in the field, a team of scientists have discovered that the levels of mercury in seabirds off the coast of British Columbia did not change over the past half a century. The new research suggests that, in fact, the mercury in seabirds is a little lower.
Although in normal conditions this would be great news, a drop in the number of fish stocks close to the surface has caused the birds to make a change in their dietary habits, which resulted in eating from areas that are lower in bacteria. This occurrence is all the more negative, as bacteria have a role in controlling the levels of mercury in their bodies.
Stable Amount Of Mercury In Seabirds
While very small, bacteria have an essential role in the biological functions of different forms of life — from people to seabirds. Researchers from the McGill University and Environment and Climate Change Canada have conducted a study, which suggests that bacteria are also essential when it comes to the birds' health.
As part of the analysis, the team employed stable isotopes in order to understand whether seabirds feeding in areas that are rich in sulfate were high in mercury. When they reached the conclusion that indeed the sulfate levels were high, they connected this fact to the higher levels of mercury in birds who feed in those areas.
The areas that are rich in sulfate are a result of the sulfate-reducing bacteria, which produce methylmercury, a very toxic substance. When the fish ingest it, it becomes easier for the seabirds who feed with the fish to get poisoned.
The research, published in the journal Environmental Science and Technology, employed seabird eggs for the analysis. The eggs were gathered from along the Pacific coast of Canada throughout a period of 47 years and were then archived by Environment and Climate Change Canada in Ottawa. As part of the research, the scientists gathered information on the levels of mercury for numerous species of seabirds throughout the same period, reaching the conclusion that the mercury levels had been stable as years passed.
Rapidly Declining Fish Population At The Surface Of The Ocean
However, during this period, seabirds in the area have changed their dietary habits, and instead of feeding themselves with fish that are located close to the surface of the water, they now eat their prey from the bottom of the ocean. Additionally, some species of fish inhabiting the areas that are located on the surface of the water have dropped.
The importance of this study lies in the fact that two of the species, which were subjected to the research, suffered a very rapid drop through the last 40 years, and the data gathered and interpreted by the scientists indicates that the growing eagle population is an essential contributing factor.
"More predators, dwindling fish stocks and mercury pollution are just some of the variables impacting seabird populations," noted Dr. Kyle Elliott, lead author of the paper, from the Department of Natural Resource Sciences at McGill.
