Effects of long-term exposure to microfibers on ecosystem services provided by coastal mussels

Abstract

The biofiltration capacity of bivalve populations is known to alleviate the effects of coastal eutrophication. However, this important ecosystem service could potentially be impaired by the increasing microplastic abundance in near shore environments. It is known that relatively large microplastics (~500µm) impair the filtration capacity of bivalves, however, the effect of smaller microplastics, and specifically microfibers, is not known even though they are more common in many natural systems and similar in size to phytoplankton, the main food source of mussels. Here, we investigated the effects of long-term exposure to microfibers (MFs), which are smaller than 100µm, on the biofiltration capacity of the blue mussel, Mytilus edulis. Our findings show that longterm exposure (here 39 days) to microfibers significantly reduced (21%) the clearance of phytoplankton (Tetraselmis sp). While previous studies have shown that larger microplastics can decrease the filtration capacity of mussels after short-term exposure, our findings suggest that, for smaller MFs, mussel's clearance capacity is significantly affected after long-term exposure (39 days in this study). This may be due to the accumulation of MFs in the digestive system. In addition, the most efficient phytoplankton consumers were more susceptible to MF accumulation in the digestive system. This suggests that prolonged exposure to MF of coastal mussels could 2 negatively impact the biofiltration of more potent individuals, thus decreasing the ecosystem service potential of the population as a whole. CapsuleWe found that long-term exposure to small microfibers can impair the phytoplankton clearance by coastal mussels.

Mussel biology: from the byssus to ecology and physiology, including microplastic ingestion and deep-sea adaptations

“…3 and Online Resource 1 for time-lapse movie), which have become a world-wide concern. Since early reports about microplastic contamination in mussels (Browne et al 2008;von Moos et al 2012;Wegner et al 2012), an increasing number of papers have been published, mainly on species of Mytilus and Perna (Chae and An 2020; Gedik and Eryasar 2020; Kazour and Amara 2020; Piarulli and Airoldi 2020; Christoforou et al 2020;Cole et al 2020;Li et al 2020a;Stamataki et al2020;Wakkaf et al 2020;Webb et al 2020;Alnajar et al 2021;Cappello et al 2021;Cho et al 2021;Klasios et al 2021;Kumar et al 2021;Liu et al 2021;Perez et al 2021;Seuront et al 2021;Wang et al 2021a,b). Considering their distributions around cities and other human habitations, mussels are ideal organisms for monitoring microplastic pollution.…”

A Paraffin Microtomy Method for Improved and Efficient Production of Standardized Plastic Microfibers

“…Polyester and PET fibers are commonly used in textiles, and nylon (polyamide) is another common polymer used in textiles, fishing gear, and other maritime equipment (Browne et al, 2011; Mishra et al, 2019). Both polymers are prevalent in the environment and have shown negative effects on aquatic organisms, such as changes in molting behavior and prey selectivity of juvenile copepods (Cole et al, 2019) and decreased filtration capacity and filtration rates of mussels (Christoforou et al, 2020; Woods et al, 2018). For the development of the paraffin microtomy method described, spools of multifilament synthetic fibers (PET‐ES305710 and nylon 6,6‐AM325705) were purchased commercially from Goodfellow.…”

“…The only prior method for making sufficient quantities of uniform microfibers ≤100 µm for laboratory experiments used a cryogenic microtome to thinly slice embedded multifilament polymer fibers (Cole, 2016). This method is more precise than other methods, is appropriate for laboratory experiments, and produces microfibers that are easily distinguishable from airborne contaminants (Christoforou et al, 2020). Although it generates high‐quality experimental microfibers, the cryomicrotomy method is time‐consuming and requires the use of a relatively uncommon instrument: a cryogenic microtome (Christoforou et al, 2020; Cole, 2016).…”

“…This method is more precise than other methods, is appropriate for laboratory experiments, and produces microfibers that are easily distinguishable from airborne contaminants (Christoforou et al, 2020). Although it generates high‐quality experimental microfibers, the cryomicrotomy method is time‐consuming and requires the use of a relatively uncommon instrument: a cryogenic microtome (Christoforou et al, 2020; Cole, 2016). The production limitations and the limited availability of cryogenic microtomes reduce the applicability of cryomicrotomy for widespread use in laboratory experiments.…”

Bivalves as Biological Sieves: Bioreactivity Pathways of Microplastics and Nanoplastics

“…This suggests that, like larger MP spheres, MP fibers may be largely eliminated via biodeposits. Recent studies with mussels indicated significant decreases in water filtration and clearance rates after 39 days of exposure to nylon fibers (35 mm long) (Christoforou et al, 2020). These kinds of studies, as well as careful reviews of research related to carbon nanotubes, are important for characterizing the potential fate and impacts of MP and NP fibers.…”