Sediment Traps: A Renowned Tool in Oceanography Applied to New Marine Pollutants

<jats:p>Particles afloat in the ocean are important components of marine element cycles. Most of this particulate matter is suspended in the sunlit surface layer and is mainly composed of microscopic living and dead organisms and fecal pellets. Aggregation of small, suspended particles into large, rapidly sinking aggregates can transport surface-​derived material to the deep ocean and the seafloor, contributing to the so-called biological pump. The comprehensive analysis of these sinking particles has increased our understanding of important biogeochemical ocean processes, such as the relationship between the rate of primary production and downward flux of particulate organic matter, the biological control of the removal of abiogenic particles from the surface ocean, and seasonal or inter­annual variations in downward particle fluxes. Sediment traps have been widely used since the late 1970s to capture the downward flux of particles for study (e.g., Staresinic et al., 1978; Knauer et al., 1979).</jats:p>

section_content: Sediment Traps: A Renowned Tool in Oceanography Applied to New Marine Pollutants By Luisa Galgani, Helmke Hepach, Kevin W. Becker, and Anja Engel Particles afloat in the ocean are important components of marine element cycles. Most of this particulate matter is suspended in the sunlit surface layer and is mainly composed of microscopic living and dead organisms and fecal pellets. Aggregation of small, suspended particles into large, rapidly sinking aggregates can transport surfacederived material to the deep ocean and the seafloor, contributing to the so-called biological pump. The comprehensive analysis of these sinking particles has increased our understanding of important biogeochemical ocean processes, such as the relationship between the rate of primary production and downward flux of particulate organic matter, the biological control of the removal of abiogenic particles from the surface ocean, and seasonal or interannual variations in downward particle fluxes. Sediment traps have been widely used since the late 1970s to capture the downward flux of particles for study (e. g., Staresinic et al., 1978; Knauer et al., 1979). 

While helping us to understand how fast "natural" elements such as carbon and nutrients (i. e., nitrogen, phosphorus, and iron) are exported from the surface to the deep ocean on various timescales, sediment traps can also provide important information on fluxes and removal rates of anthropogenic pollutants such as plastic particles. In contrast to the surface-tethered drifting array, which permits estimations of downward particle fluxes in open waters, the year-round coastal array serves as an in situ particle collector that allows us to study how plastic particles correlate with organic particle abundance over seasonal cycles. This long-term monitoring strategy will enable us to track changes in the marine ecosystem and in plastic concentrations, and will potentially provide information on plastic interaction with biogeochemical and physical processes that drive long-term ecosystem changes.

section_content: Sediment trap equipment, including that used for our stud-
section_name: BLANKS AND CONTAMINATION CONTROL

section_name: ACKNOWLEDGMENTS

section_content: Jon Roa, Lindsay Scheidemann, Sandra Golde, Cathleen Schlundt, and the Technology & Logistic Centre at GEOMAR are gratefully acknowledged for their continuous help in the deployment and recovery of the sediment traps over the seas and years. The deployments of the sediment traps are made possible thanks to funding from the Helmholtz Association (GEOMAR) and the Bundesministerium für Bildung und Forschung, BMBF, under the joint research project FACTS ID 03F0849B, JPI-Oceans. LG is funded by the European Union 's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 882682.
section_name: ACKNOWLEDGMENTS