We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
A Critical Examination of the Role of Marine Snow and Zooplankton Fecal Pellets in Removing Ocean Surface Microplastic
AI summary Read the abstract
This review critically examines the hypothesized role of marine snow and zooplankton fecal pellets in exporting surface microplastics to deep ocean sediments, finding that while biological packaging can enhance sinking rates, the quantitative contribution of this pathway to resolving the 'missing plastic' problem remains uncertain. The authors call for improved field measurements and modeling to test these mechanisms rigorously.
Numerical simulations and emissions estimates of plastic in and to the ocean consistently over-predict the surface inventory, particularly in the case of microplastic (MP), i.e. fragments less than 5 mm in length. Sequestration in the sediments has been both predicted and, to a limited extent, observed. It has been hypothesized that biology may be exporting a significant fraction of surface MP by way of marine snow aggregation and zooplankton faecal pellets. We apply previously published data on MP concentrations in the surface ocean to an earth system model of intermediate complexity to produce a first estimate of the potential global sequestration of MP by marine aggregates, including faecal pellets. We find a MP seafloor export potential of between 7.3E3-4.2E5 metric tons per year, or about 0.06-8.8% of estimated total annual plastic ocean pollution rates. We find that presently, aggregates alone would have the potential to remove most existing surface ocean MP to the seafloor within less than 2 years if pollution ceases. However, the observed accumulation of MP in the surface ocean, despite this high potential rate of removal, suggests that detrital export is an ineffective pathway for permanent MP removal. We theorize a prominent role of MP biological fouling and de-fouling in the rapid recycling of aggregate-associated MP in the upper ocean. We also present an estimate of how the potential detrital MP sink might change into the future, as climate change (and projected increasing MP pollution) alters the marine habitat. The polar regions, and the Arctic in particular, are projected to experience increasing removal rates as export production increases faster than MP pollution. Northern hemisphere subtropical gyres are projected to experience slowing removal rates as stratification and warming decrease export production, and MP pollution increases. However, significant uncertainty accompanies these results.
More Papers Like This
Slow biological microplastics removal under ocean pollution phase-out trajectories
AI summary Read the abstract
Modeling and observation of biological microplastic removal from the ocean surface -- through incorporation into marine snow and fecal pellets that sink -- suggests this process is too slow to meaningfully offset continued plastic pollution inputs.
Modelling the global biological microplastic particle sink
AI summary Read the abstract
Researchers modeled the global biological sink for microplastic particles, estimating that ingestion and fecal pellet packaging by marine zooplankton accelerates the sinking of buoyant plastics to depth. This study suggests that biological processes may account for a substantial portion of the missing plastic that disappears from ocean surface surveys.
Hitchhiking into the Deep: How Microplastic Particles are Exported through the Biological Carbon Pump in the North Atlantic Ocean
AI summary Read the abstract
This study investigated how microplastic particles are exported from the ocean surface to the deep sea through the biological carbon pump in the North Atlantic. Microplastics were found associated with sinking organic aggregates (marine snow), fecal pellets, and zooplankton, demonstrating biological packaging as a key mechanism for deep-sea plastic transport.
Role of Marine Snows in Microplastic Fate and Bioavailability
AI summary Read the abstract
Laboratory experiments demonstrated that marine snow — organic aggregates formed naturally in the ocean — can incorporate microplastics and transport them from surface waters toward the seafloor. The findings provide a physical mechanism explaining how buoyant microplastics sink to become a major component of seafloor sediment pollution.
Modelling the sedimentation of macro-, micro- and nanoplastics in the ocean from surface to sediment
AI summary Read the abstract
This study modeled the sedimentation of macro-, micro-, and nanoplastics in the ocean, focusing on how the biological pump and marine snow aggregation transfer plastic from surface waters to the deep sea. The model showed that biological processes dramatically accelerate the removal of plastic particles from the ocean surface, with implications for estimates of marine plastic residence times.
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.