0
Article Tier 2 Detection Methods Environmental Sources Marine & Wildlife Policy & Risk Sign in to save

Sea surface microplastics in the Galapagos: Grab samples reveal high concentrations of particles <200 μm in size

The Science of The Total Environment 2024 18 citations

AI summary Read the abstract

Researchers compared two microplastic sampling methods in the coastal waters of the Galapagos Islands and found dramatically different results depending on the technique used. Whole seawater grab samples filtered to 1.2 micrometers revealed microplastic concentrations four orders of magnitude higher than traditional plankton net tows with 200-micrometer mesh. The study suggests that standard ocean sampling methods may vastly underestimate the true abundance of small microplastics in marine environments.

Study Type Environmental

Plastic pollution in the oceans is increasing, yet most global sea surface data is collected using plankton nets which limits our knowledge of the smaller and more bioaccessible size fraction of microplastics (<5 mm). We sampled the biodiverse coastal waters of the Galapagos Island of San Cristobal, comparing two different microplastic sampling methodologies; 1 l whole seawater grab samples filtered to 1.2 μm and sea surface plankton tows with a net mesh size of 200 μm. Our data reveal high concentrations of microplastics in Galapagos coastal waters surrounding the urban area, averaging 11.5 ± 1.48 particles l-1, with a four-order of magnitude increase in microplastic abundance observed using grab sampling compared with 200 μm plankton nets. This increase was greater when including anthropogenic cellulose particles, averaging 19.8 ± 1.86 particles l-1. Microplastic and anthropogenic cellulose particles smaller than 200 μm comprised 44 % of the particles from grab samples, suggesting previous estimates of microplastic pollution based on plankton nets likely miss and therefore underestimate these smaller particles. The particle characteristics and distribution of these smaller particles points strongly to a local input of cellulosic fibres in addition to the microplastic particles transported longer distances via the Humbolt current found across the surface seawater of the Galapagos. Improving our understanding of particle characteristics and distributions to highlight likely local sources will facilitate the development of local mitigation and management plans to reduce the input and impacts of microplastics to marine species, not just in the Galapagos but globally.

More Papers Like This

Article Tier 2

Microplastic pollution in the North-east Atlantic Ocean surface water: How the sampling approach influences the extent of the issue

AI summary Read the abstract

Researchers compared two different sampling methods for measuring microplastic pollution in the open North-east Atlantic Ocean and found that results varied dramatically depending on the technique used. The grab sampling method captured significantly more small particles than the traditional Manta trawl approach. The study demonstrates that the choice of sampling method can fundamentally change our understanding of how much microplastic pollution exists in ocean waters.

Article Tier 2

A comparison of sampling methods for seawater microplastics and a first report of the microplastic litter in coastal waters of Ascension and Falkland Islands

AI summary Read the abstract

Microplastic concentrations measured by bottle grab sampling (filtered to 0.45 μm) were roughly 1,000-fold higher than estimates from net-based methods, demonstrating that commonly used plankton trawls dramatically underestimate microplastic abundance. The study also documents for the first time that microplastics are present in the waters around Ascension Island and the Falkland Islands, establishing contamination at remote South Atlantic locations.

Article Tier 2

Are we underestimating microplastic abundance in the marine environment? A comparison of microplastic capture with nets of different mesh-size

AI summary Read the abstract

By sampling marine water simultaneously with 333 µm and finer nets, researchers demonstrated that standard 333 µm sampling nets miss the majority of microplastics present, with finer nets capturing orders of magnitude more particles and revealing severe underestimation in existing abundance data.

Article Tier 2

Size and shape matter: A preliminary analysis of microplastic sampling technique in seawater studies with implications for ecological risk assessment

AI summary Read the abstract

This study showed that sampling with coarse-mesh towed nets significantly underestimates microplastic concentrations in seawater, particularly for fibrous particles, raising concerns about the accuracy of published abundance estimates.

Article Tier 2

Comparative study of three sampling methods for microplastics analysis in seawater

AI summary Read the abstract

Researchers compared three microplastic sampling methods for seawater — direct 0.45 µm filtration, 20 µm pre-concentration followed by 0.45 µm filtration, and Manta trawl with 150 µm mesh — finding orders-of-magnitude differences in reported abundance across methods, underscoring the critical need for standardized protocols.

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