Temporal Trends in Marine Litter at Three Stations of the HAUSGARTEN Observatory in the Arctic Deep Sea

Abstract

The deep sea is a major sink for debris; however, temporal changes and underlying mechanisms of litter accumulation on the seafloor remain unclear. Photographic surveys at the long-term ecological research (LTER) observatory HAUSGARTEN, in the eastern Fram Strait, have enabled the assessment of spatial and temporal variability of seafloor litter in the Arctic. Previous studies of time-series data (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) reported an increase in litter quantities from the northernmost and central stations. Here, we extended the analysis by three years until 2017 and included data from the southernmost station. A total of 16,157 images covering 60.5 km 2 were analyzed and combined with previous studies, to determine litter density, type and size compositions. Moreover, the interaction of litter with epibenthic megafauna was evaluated. Indicators of local maritime traffic, fisheries activity and summer sea ice extent were examined as potential drivers. The mean annual litter density ranged between 813 ± 525 (SEM) and 6,717 ± 2,044 (SEM) items km −2 . Litter density clearly increased over time, and the northernmost station experienced the strongest increase. Plastics dominated at two of the stations whereas the northern station harbored mainly glass. Small-sized items accounted for 63%. Interaction with epibenthic fauna was frequent, especially with sessile organisms. Litter densities correlated with fishing and tourism vessel abundance, but no correlation was found with summer sea ice extent. This 15-year record of marine litter shows that even secluded Arctic ecosystems become increasingly subject to plastic pollution and that it will likely continue in the face of growing global plastic production rates and ineffective waste management policies.

Marine Debris Floating in Arctic and Temperate Northeast Atlantic Waters

“…Items were categorised according to their estimated sizes as small (-<10cm), medium (10≤ x ≤ 50cm) or large (>50 cm) to allow for a comparison of the size distribution of debris items from the sea surface (this study) and the deep seafloor (Bergmann and Klages, 2012;Tekman et al, 2017;Parga Martínez et al, 2020). The minimum size of floating debris recorded by the observers was 1 cm.…”

“…However, relatively little is known about concentrations of floating marine debris over vast stretches of the open ocean, especially in remote geographic regions such as the polar oceans (Bergmann et al, 2022). Recent surveys revealed substantial amounts of marine debris on Arctic beaches (Bergmann et al, 2017a;Falk-Andersson et al, 2019;Haarr et al, 2020) and on the deep Arctic seafloor (Parga Martínez et al, 2020). Meanwhile, it has been well established that polar regions have become significantly polluted by plastics and that direct land-based input is only one part of the problem (Bergmann et al, 2017a;Suaria et al, 2020).…”

“…This complex circulation pattern complicates the identification of sources and pathways of Arctic plastic pollution. Nevertheless, a decade of intense research highlighted the high contribution of sea-based input (Bergmann et al, 2017a;Węsławski and Kotwicki, 2018), long-distance transport (Cózar et al, 2017), and deposition and accumulation on the seafloor (Parga Martínez et al, 2020).…”

Weathering Plastics as a Planetary Boundary Threat: Exposure, Fate, and Hazards

“…The most common fate of marine microplastics is often claimed to be settling on the sea bed, or suspension in deep water columns. − Several studies investigated the settling behavior of individual particles of various polymers in different sizes and shapes, , subject to (controlled) weathering conditions and biofouling . These studies have confirmed that their settling behavior follows semiempirical fluid mechanic laws for fluid drag resistance of objects in relative motion to their ambient fluid (i.e., Newton’s second law, leading to Stokes’ law, though empirically corrected for turbulence generation in the particle’s wake). , However, what complicates the prediction of transport and sedimentation of plastics is their wide variety in sizes and shapes, which is made even more complex due to biofilm formation, fragmentation processes, and heteroaggregate formation, diversifying over time and space.…”

A Delphi Based Approach to the Assessment of New Marine Litter Reduction and Processing Technologies

“…Plastic debris is the main contributor to marine litter and the tendency is for it to grow still more following increases in the production of plastic (367 million tonnes in 2020 as mentioned in Plastics Europe, 2020). Plastics are estimated to account for approximately 73% of the total waste in the ocean, while 8 million tonnes of plastic arrive in the oceans every year (Parga Martıńez et al, 2020). Hohn et al (2020) mention future projections according to which the amount of plastic waste could double by 2050 if no strategies to reduce waste are implemented.…”