Spiders living near lakes and rivers may be responsible for contaminating land animals with mercury, suggests a new study.
Researchers found terrifying long-jawed arachnids that feast on fish and insects could be the vehicle that transfers mercury pollution from aquatic to terrestrial environments.
A team from the American Chemical Society (ACS) concluded that though not all water-dwelling spiders may be responsible, some species could lead to land animals becoming infected.
The study, published in the journal Environmental Science & Technology Letters, focused on arachnid species living near to lakes and rivers.
These spiders tend to feast on aquatic insects like dragonflies.
Mercury can enter these waterways through industrial pollution and other human activities, but the metal can also derive from natural sources.
Mercury poisoning can lead to digestive problems and even to kidney or brain damage in animals.
In water, microbes quickly convert mercury into methylmercury – the element’s most toxic and bioavailable form which can grow and increase in organisms further up the food chain.
Scientists have increasingly looked towards water-dwelling spiders as the connecting bridge between water and land, as they eat insects from the water and subsequently become prey themselves for animals such as birds, bats and amphibians.
Dr. Sarah Janssen and her team collected long-jawed spiders along two tributaries to Lake Superior – the largest freshwater lake in the world by surface area, bordering Canada and the United States – and sampled sediments, dragonfly larvae and yellow perch fish from these same waterways.
They then measured and identified the mercury sources, including direct industrial contamination, precipitation and runoff from soil.
The researchers found that the origin of the mercury in the sediments was the same up the aquatic food chain in wetlands, reservoir shorelines and urban shorelines.
For example, in areas where sediment was found to contain higher proportions of industrial mercury, the same was true for the dragonfly larvae and the spider and yellow perch tissues collected.
After analyzing their data, the researchers concluded that long-jawed spiders could explain how mercury pollution moves from aquatic environments to terrestrial wildlife.
They added that this could help to inform tools to monitor remediation activities.
However, their data did suggest that not every species of spider living near rivers and lakes was a certain vehicle for mercury to climb up the food chain.
Produced in association with SWNS Talker