Arctic marine litter: Composition and sources investigated by citizen scientist "super-users".

Combating the challenge of marine litter requires an understanding of its distribution and accumulation for mitigative measures, and its sources for targeted preventative measures. The latter is generally not well assessed through most beach litter registration protocols available to citizen scientists. Deep Dives were specifically developed to provide management with additional relevant data on the sources of and behaviours leading to littering in the Arctic. In this project, the Deep Dive protocol was used as an add-on to the Norwegian national volunteer beach cleanup registration protocol. Litter was cleaned and registered from 9 locations in the Svalbard archipelago 2022-2023 in collaboration with two groups of citizen scientists: members of the Arctic Research Group and students from Svalbard Folkehøgskole. These were given specialised training as "super-users" to apply this more complex beach litter registration protocol. The experience of the volunteers was generally positive and the data quality good, although some need for additions to the training was highlighted to reliably categorise some challenging items. In the future, citizen scientists could contribute significantly to the collection of management-relevant data on marine litter in the Arctic provided adequate training, resources, and a user-friendly data registration portal.