Skip to content

Do coral reefs act as sinks for microplastics?

  • Marcelo O. Soares
  • Lucia Rizzo
  • Antonio Rodrigues Ximenes Neto
  • Yasmin Barros
  • José Eduardo Martinelli Filho
  • Tommaso Giarrizzo
  • Emanuelle F. Rabelo

Abstract

Microplastic (MP) pollution has been detected in coral reefs, raising concerns regarding its global impact. Although they cover a small portion (<1%) of the total area of the world's oceans, coral reefs are geological and biological structures that trap MPs and disproportionately enhance their accumulation. In this review, we attempted to understand how coral reefs act as short- and long-term sinks for MPs. We describe five characteristics that lead to the enrichment of microplastics in coral reefs: 1) adhesion on reef-building corals at distinct depths; 2) ingestion by reef organisms (e.g., suspension feeders, such as sponges, ascidians, and corals), bioconcentration, and formation of short-term (i.e., years to decades) biological sinks for MPs; 3) formation of long-term (i.e., centuries) MP sinks in coral skeletons and unconsolidated subsurface sediments; 4) reduction of sediment resuspension and seafloor turbulent kinetic energy by complex marine forest architecture that reduces bottom shear stress, facilitates the retention, and deposition of small (<0.5 mm) and high-density floating MPs; and 5) diagenesis of Anthropocene sedimentary rocks containing MPs. We estimate that reef processes may remove more than 10% of floating MPs in shallow tropical waters yearly. Statistical results show that microplastic abundance for reef-building corals are higher than values found in reef sediments and especially in seawater. Moreover, pellets, films, foams and mainly fragments and fibers have been found. These field-based data support our hypothesis of sinks in the reef sediments and organisms. We highlight the role of these seascapes in the interception of MPs as traps and sinks in reef sediments, biota, and carbonate frameworks. As coral reefs are prone to MP accumulation and can become pollution hotspots, global initiatives are necessary to conserve these rich ecosystems and prevent rapidly increasing plastic pollution.

Cite this activity

Soares M.O., Rizzo L., Ximenes Neto A.R., Barros Y., Martinelli Filho J.E., Giarrizzo T. and Rabelo E.F. (2023) Do coral reefs act as sinks for microplastics? 337: 122509. 10.1016/j.envpol.2023.122509

Details

Research topics
Date 09.09.2023
Volume 337
Pages 122509
Open Access Closed Access
Open Access Status Closed Access
Eprints_link https://cris.leibniz-zmt.de/id/eprint/5316
Peer-Reviewed

Research Spectrum

The content on this page is maintained by the authors.