Microplastic Pollution: a potential threat to the intertidal invertebrate food web Zoe Sloan
Microplastic Pollution • Microplastics are generally described as plastic particles
with a diameter of less than 5mm. • There are several ways in which microplastics enter the
marine environment • Microplastics that are commonly recorded in the oceans
include polyethylene (PE), polypropylene (PP) and polystyrene (PS)
• Depending on their origin they can be classified as:• Primary Microplastics • Secondary Microplastics
Distribution of Microplastics
Sediment samples were collected from 18 shores across 6 continents. All 18 shores has microplastics present (Brown et al., 2011)
Interactions with Marine Organisms • Ingestion:
• The most common way that microplastics will interact with marine biota
• Primary- and low-trophic level organisms are particularly susceptible• Translocation:
• After ingestion, microplastics have several possible fates • They can be egested as faeces, taken up by the epithelial lining in the
gut, or translocated to other tissues. • Absorption of Pollutants:
• Microplastics are highly susceptible to contamination by various pollutants.
• Including heavy metals, endocrine disruptors and POPs.
Trophic Transfer of Microplastics
• A study in 2014 by Setala et al., indicated that mesozooplankton could uptake polystyrene (PS) spheres.
• When mysid shrimp were exposed to the contaminated zooplankton, all individual shrimps had PS spheres in their intestines.
The ingestion of microplastics by primary tropic-level organisms, such as phytoplankton and zooplankton, presents a potential for transfer into the food web.
Image Source: Wright et al. 2013
Microplastics and the Intertidal Food Web• Uptake by the Blue Mussel (Mytilus edulis)
• Mussels are suspension feeding bivalves. • Since microplastics have a similar size range to planktonic organisms,
they are considered bioavailable to such invertebrates. • Studies have indicated that mussels are able to uptake microplastics
through feeding.• Transfer to Crabs
• The blue mussel is a key prey species to shore crabs (Carcinus maenas) and the edible crab (Cancer pagurus)
• In 2004, a study by Watts et al., demonstrated that microplastics can be transferred to shore crabs after ingesting contaminated mussels.