0
Article Tier 2 Sign in to save

Modeling the convergence of buoyant debris in the Indian Ocean: Insights from surface drifter trajectories and Lagrangian simulations

AI summary Read the abstract

Researchers used six surface drifter trajectories in the Southern Indian Ocean, combined with Lagrangian particle simulations that incorporate Stokes drift, to map a plastic convergence zone in the western basin fed by the Agulhas Return Current and South Equatorial Current—filling a major gap in understanding where buoyant debris accumulates in this under-monitored ocean.

Study Type Environmental

While it is known that plastics floating on the ocean surface converge at the center of the five subtropical gyres, this convergence remains poorly documented in the Indian Ocean, particularly due to a lack of in situ measurements. In this study, we use the trajectories of six surface drifters, active between December 2024 and May 2025 and likely representative of the behavior of floating plastic debris, to develop an optimized current product that best reproduces their observed drift. This product is constructed as a weighted sum of three components: general circulation, tidal currents, and Stokes drift. The inclusion of Stokes drift appears essential for minimizing errors. Particle convergence is then studied using this optimized product in Lagrangian simulations performed over the Southern Indian Ocean. These simulations reveal a convergence zone located in the western part of the basin, fed by two main pathways via the Agulhas Return Current and the South Equatorial Current, and characterized by a particularly intense escape route via the Agulhas Current. The interannual variability of the convergence zone is also discussed.

More Papers Like This

Article Tier 2

Role of Indian Ocean Dynamics on Accumulation of Buoyant Debris

AI summary Read the abstract

Researchers used ocean circulation modeling to investigate the role of Indian Ocean dynamics in accumulating buoyant marine plastic debris, examining how Ekman convergence and regional current patterns shape the distribution of floating debris in the Indian Ocean subtropical gyre.

Article Tier 2

Pathways of marine debris derived from trajectories of Lagrangian drifters

AI summary Read the abstract

Researchers applied a probabilistic model to global satellite-tracked ocean drifter trajectories to map marine debris pathways, identifying five subtropical convergence zones maintained by Ekman currents where floating debris — including microplastics — preferentially accumulates, confirming predictions with direct ocean surface measurements.

Article Tier 2

Beaching patterns of plastic debris along the Indian Ocean rim

AI summary Read the abstract

Researchers used Lagrangian particle-tracking simulations to model the beaching patterns of plastic debris along the Indian Ocean rim, finding that the absence of a subtropical gyre in the Northern Hemisphere Indian Ocean means plastics likely accumulate on coastlines rather than forming a garbage patch. Results showed a large amount of plastic ends up on coastlines in the Northern Indian Ocean while some crosses the equator into the Southern Hemisphere.

Article Tier 2

Modelling the accumulation and transport of floating marine micro-plastics around South Africa.

AI summary Read the abstract

Numerical particle tracking models were used to simulate the pathways, transport, and accumulation of floating microplastics around the South African coastline. The model provides the first quantitative estimates of how different plastic densities and sizes distribute around South Africa's marine environment, identifying accumulation hotspots.

Article Tier 2

Zonal Distribution Characteristics of Microplastics in the Southern Indian Ocean and the Influence of Ocean Current

AI summary Read the abstract

Microplastic concentrations were measured in seawater across the southern Indian Ocean along transects influenced by major ocean currents, finding that plastic distribution was shaped by circulation patterns with higher concentrations in convergence zones. The study provides baseline data on microplastic pollution in a relatively understudied and remote ocean region.

Research digests by email

When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.

Email me about

Share this paper