- 1Center for Marine Sensors, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26382 Wilhelmshaven, Germany
- 2Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26111 Oldenburg, Germany
- 3Department of the Built Environment, Aalborg University, 9220 Aalborg East, Denmark
- 4GEOMAR Helmholtz Center for Ocean Research Kiel, 24148 Kiel, Germany
- 5Chair of Environmental Chemistry and Air Research, Technische Universität Berlin, 10623 Berlin, Germany
Microplastics (MPs) are pervasive contaminants, yet understanding their pathways and fate in the marine environment remains unclear. A key challenge is the lack of in-situ, complementary measurements linking MP quantification with oceanographic parameters, particularly concerning submesoscale processes and density fronts. Submesoscale dynamics, including filaments, eddies, and fronts, significantly influence the transport and accumulation of MPs by creating convergence zones and sharp density gradients. Density fronts serve as critical hotspots for MP aggregation, concentrating particles through upwelling and downwelling processes. Despite their importance, these interactions remain poorly studied, emphasizing the need for integrated approaches to directly measure the interplay between MPs and the physical processes that drive their distribution.
This study addresses this gap by utilizing in-situ measurements collected with an autonomous surface vehicle (ASV) in the southern North Sea, simultaneously collecting water samples for MP analysis and key oceanographic data. The ASV simultaneously sampled air, sea surface microlayer, and underlying water for MP analysis. A weather station and conductivity, temperature, and depth (CTD) sensors were deployed on the ASV to further contextualize the distribution of MPs. Additionally, CTD profiles were obtained by an accompanying research vessel to investigate the influence of stratification and temporal dynamics on MP distribution. An acoustic Doppler current profiler measured water current velocities and flow direction.
The measurements underscore the pivotal role of submesoscale fronts and filaments in shaping the accumulation and distribution of MP. Upwelling and downwelling processes at these fronts and filaments concentrated MP up to 30.48 µg MP L⁻¹, and distributed MPs vertically across depth profiles and horizontally across fronts. Wind direction was found to influence the presence of MP in the atmosphere, while wind speeds appeared to enhance heterogeneity in MP composition and concentration within the water.
Submesoscale fronts and filaments are highlighted as key zones for MP accumulation, driven by the interplay of horizontal and vertical water flow linked to ageostrophic circulation. The data provide novel insights into their transport mechanisms in the marine environment.
How to cite: Meyerjürgens, J., Goßmann, I., Albinus, M., Achtner, C., Robinson, B.-T., Held, A., Lehners, C., Gassen-Bertzbach, L., Ayim, S. M., Badewien, T. H., Scholz-Böttcher, B. M., and Wurl, O.: What Influences Microplastic Distribution in the Marine Environment? A Study Highlighting the Role of Fronts and Submesoscale Processes in the North Sea, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17177, https://doi.org/10.5194/egusphere-egu25-17177, 2025.
