Fram pollution observatory anthropogenic debris pollution in the Arctic
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|Authors:||Tekman, Mine B.||Supervisor:||Bergmann, Melanie||1. Expert:||Iversen, Morten H.||Experts:||Freund, Holger||Abstract:||
The exponential increase in plastic production is reflected in the amount of waste produced, yet the waste management infrastructures and practices have been insufficient to regulate and govern the extensive plastic waste entering the environment, which was estimated as 19 – 23 million metric tons in 2016 for aquatic systems. Disturbing footage of pervasive pollution or an increasing number of sightings of encounters with charismatic species not only draw public attention but also boosted an interest within the scientific community. Soon enough, it was realized that anthropogenic debris pollution has even reached uninhabited remote islands and polar regions. Globally, there are thousands of studies on regional or large-scale anthropogenic debris pollution, yet a holistic approach to identify the distribution patterns is mostly lacking. In this regard, with the aim of measuring anthropogenic debris and microplastic pollution levels in all ecosystem compartments in the Arctic, the FRAM Pollution Observatory represents a rare case. The comparison of findings from different ecosystem compartments allowed us to explore and identify the sources, transportation pathways and sinks of anthropogenic debris in the Arctic.
In this dissertation, I summarise the findings obtained by the studies of the FRAM Pollution Observatory. The main chapters deal with the distribution of macro-debris floating in Arctic surface waters (Chapter 2.1) and on the deep seafloor (Chapter 2.2) and with the distribution of microplastic throughout the water column and in deep-sea sediments (Chapter 3). However, in the general discussion (Chapter 4), I focused on the findings from all ecosystem compartments including sea ice, snow, Svalbard beaches and biota. Overall, the majority of anthropogenic macro-debris in the Arctic is plastic. In all ecosystem compartments, high levels of pollution were detected, which are comparable to those reported from more densely populated regions of the world. Quantities of floating macro-debris in Arctic waters were not different to those in the North Sea. Higher concentrations of floating macro-debris measured in summer than in autumn and spring highlighted the indirect effect of decreasing sea ice extent, which has opened new passages for maritime activities. Between 2002 and 2014, a significant increase in macro-debris concentrations on the deep seafloor was identified. Deep-sea sediments are an ultimate sink for microplastic pollution. Throughout the water column, highest microplastic concentrations were observed in the ocean surface layer and decreased towards greater depths as did organic matter distribution, too. Microplastic particles between 10 and 100 µm accounted for 99.9% of the microplastics detected in the water column, raising concerns about their bioavailability. A different vertical profile at the Molloy Deep suggested that local oceanographic conditions and bathymetry affect microplastic distribution. The simulation of drift trajectories indicated the North Atlantic Current as the main carrier of anthropogenic debris to the Fram Strait, yet with a contribution of the Transpolar Drift carrying debris from the Siberian Arctic. Sea ice drift trajectories identified the Kara and Laptev Seas as another source of pollution in the Fram Strait. As for the other studies of the FRAM Pollution Observatory, Arctic sea ice is a temporary sink of microplastic, scavenging particles from surrounding waters during ice formation and releasing them upon melting. Microplastic concentrations in Arctic snow, as an indicator of atmospheric microplastic pollution, showed considerable concentrations, which are comparable to those from urban areas. A preliminary analysis of microplastic distribution in the water column, sediment and snow showed significant differences in concentrations between sediment and other ecosystem compartments, but not between those obtained from the water column and snow. This finding points out a turnover at the sea-air interface. Last but not least, zooplankton organisms in the Fram Strait were found to have ingested microplastic, confirming the bioavailability of these anthropogenic pollutants.
Although, a substantial number of findings helped me to understand the pollution levels and trends of anthropogenic debris in the Arctic, they raised a lot more questions to be answered. We still do not know, how and when such a pervasive pollutant will affect the biodiversity, biogeochemical cycles in the Arctic and eventually global climate patterns. I hope, we will be able to regulate our plastic production, consumption and waste management before such destructive impacts occur.
|Keywords:||microplastics; marine debris; Plastic; Arctic; pollution||Issue Date:||20-Jan-2023||Type:||Dissertation||DOI:||10.26092/elib/1988||URN:||urn:nbn:de:gbv:46-elib65038||Institution:||Universität Bremen||Faculty:||Fachbereich 05: Geowissenschaften (FB 05)|
|Appears in Collections:||Dissertationen|
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