We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Transport and retention of sinking microplastics in a well-mixed estuary
AI summary Read the abstract
Researchers used numerical particle-tracking experiments to examine how sinking microplastics are retained in well-mixed estuaries under varying tidal and freshwater flow conditions. They found that over 90% of sinking particles were retained in the estuary, with retention rates highly sensitive to particle density and size. The study confirms that estuaries can act as significant accumulation zones for microplastics, trapping particles before they reach the open ocean.
Estuaries have been shown to be potential hotspots of microplastic accumulation, but the hydrodynamic conditions and particle properties that control this process need further investigation. We have designed a series of numerical particle-tracking experiments to examine the sensitivity of retention in estuaries to particle size, particle density and varying tides and freshwater flow. At the end of the simulation, over 90 % of sinking particles are retained in the estuary, and the retention rate is further increased by high river runoff. In contrast, increased river discharge increases the number of marginally-buoyant (i.e. density close to estuarine water) particles that escape the estuary. Larger particle size tends to limit the downstream transport of sinking particles but can facilitate the transport of marginally-buoyant particles. Tidal asymmetry, vertical turbulent mixing and the vertical structure of the subtidal circulation are proposed as the underlying mechanisms controlling the fate of particles.
More Papers Like This
Settling of buoyant microplastic in estuaries: The importance of flocculation
AI summary Read the abstract
Researchers demonstrated that flocculation causes buoyant microplastics to settle 5-21 times faster in estuarine waters than in freshwater, supporting the concept that estuaries act as traps that reduce the overall microplastic load reaching the open ocean.
Trapping of floating MP in estuaries, the importance of flocculation
AI summary Read the abstract
Laboratory experiments showed that when microplastics enter estuaries and encounter salt water, they can become entangled in flocs — aggregates of organic particles and sediment — causing them to sink and be trapped in estuarine sediments rather than reaching the open ocean. This flocculation process in estuaries may represent a major, previously underestimated sink for river-borne microplastics. Understanding this trapping mechanism is important for accurately predicting how much plastic actually makes it from rivers to the sea.
Physical Controls on Microplastic Retention in Estuarine Systems: Interactions Between Hydrodynamics, Stratification, Bathymetry, and Particle Properties
AI summary Read the abstract
This review synthesizes how tidal patterns, river flow, water layering (stratification), estuary shape, and plastic particle properties together determine whether microplastics entering estuaries get trapped in sediments or flushed out to sea. Understanding these physical controls matters because estuaries are critical transition zones — nursery habitats for fish, shellfish, and migratory birds — and knowing where microplastics accumulate helps predict which species and communities face the highest exposure.
A quantitative approach for estimation of the settling velocity of flocculated microplastics in estuaries
AI summary Read the abstract
Researchers developed a quantitative approach to model how flocculation — the clumping of microplastic particles with suspended sediment — affects their sinking speed in estuarine environments. Understanding settling velocity is important for predicting where microplastics accumulate in estuaries, which are both highly productive ecosystems and critical zones for human fisheries.
Investigating microplastic behaviour in a well-mixed estuary
AI summary Read the abstract
This study used a 3D computer model to track how microplastics move through a tidal estuary in Wales, exploring whether estuaries trap or release plastics into coastal waters. Understanding this is important for predicting microplastic exposure in areas used for fishing and recreation.
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.