Photos by Bethan Hall-Jones
Eider ducks (Somateria mollissima) can be found all around the coast of Iceland. Eiders form large breeding colonies during springtime and one of these breeding colonies inhabits the Skálanes Nature and Heritage Centre. The eiders lay their eggs in late spring or early summer and the females incubate their eggs for 24-26 days. The male eiders roam around in the sea to feed on mussels and do not participate in taking care of their young. The nesting female eiders fast for the duration of the incubation period to avoid spending time away from their eggs. They only leave the nests unattended for short periods of time to walk around, preen or drink water.
Female Eider on river nest 9
In recent years, more and more plastic pollution has been detected in remote areas, including the coast of Iceland. Even areas with relatively low levels of human activity in Iceland can be affected by plastic pollution, due to ocean currents bringing in plastics from mainland Europe. One of the most common forms of plastic found in natural water sources are microfibres. Most of the microfibres we see originate from fabric production and washing laundry.
The Iceland Expedition’s eider project at Skálanes focuses on investigating the accumulation of microfibres in nesting eider females and their drinking water sources. In this project, the accumulation of microfibres in the eiders is detected by analysing their faeces. Collecting faecal samples from eiders at Skálanes is surprisingly easy, as the nesting eiders defecate on their eggs and the surrounding vegetation when they get scared by a human approaching. Their faeces are extremely smelly to protect their eggs from predators.
Still water nest 25
In total 50 eiders were chosen to be a part of the sample in this project. 25 of these eiders have their nests near still water ponds and the other 25 eiders nest near a fast-flowing stream. Each day for the first two and a half weeks at Skálanes, each of the eider nests were visited once a day to collect faecal samples. Most of the eiders did not defecate every day they were visited, but in total over 70 faecal samples were successfully collected from the nests. Some of the eiders were more stubborn than others and refused to leave the nest, making it impossible to get a sample.
Faeces samples being carefully collected
Water samples were collected three times during the sampling period. The water samples were collected each week from five ponds and five different parts of the stream. As the nesting eiders do not feed on anything during the incubation period, any plastics they might ingest should come from their drinking water source. Thus, analysing the water samples will allow us to see whether the eiders accumulate plastics from their drinking water, or if the plastics that are detected are remains of the plastics ingested from food eaten before the nesting period.
There are many research questions that can be investigated in this study. Firstly, the microfibre content in the different water source types can be compared to see whether more microfibres accumulate in the still water sources compared to running water sources. Similarly, plastic accumulation in the faecal samples can be compared between the eiders that use the running water source and the eiders that use the still water sources. As the faecal samples were collected for most of the nesting period of the eiders, changes in the accumulation of microfibres during the nesting period can be analysed. Lastly, the sizes of the microfibres found will be recorded to get an understanding of the sizes of microfibres that are present in the water sources or accumulated in the eiders´ faeces.
Microfibre found in an early faeces sample
So far, the study has been very successful. Now that the nesting period is reaching its end, it is time to analyse all of the smelly faecal samples and the water samples in the lab. So far, a few microfibres have been detected in the faecal samples, suggesting that the eiders at Skálanes might be affected by plastic pollution. But a lot more work is to be done to get better conclusions of the extent of microfibre accumulation in eiders and their drinking sources.