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Suspension-feeding mollusks (e.g., bivalves) play a key role in improving the water quality of coastal environments by filtering out suspended matter from the water column. Microplastics are becoming ubiquitous in the marine environment, so it is important to understand if these particles affect feeding processes of bivalves. Additionally, previous studies regarding the impact of microplastic on bivalve physiology have not independently tested for the effects of surfactants which are often added to commercially available plastic particles to prevent aggregation. We measured the clearance rate of mussels (Mytilus edulis) exposed to one type of microplastic and three common surfactants. Mussels were given a dose of microalgal food (1 x 104 cells/mL) and 10-m polystyrene spheres (Polybead; 1 x 104 beads/mL). Experimental treatments tested were washed microspheres and microspheres coated with each of the following surfactants at a concentration of 2mg/L: triton X-100, benzalkonium chloride, and sodium dodecyl sulfate. These surfactants are nonionic, cationic, and anionic, respectively. Control mussels were given a microalgal diet only (2 x 104 cells/mL). Each mussel was placed in an individual 1-L chamber and exposed to one of the aforementioned treatments. Water samples were taken at the start of the experiment (t=0) and then every 10 minutes for 30 minutes to determine clearance rates. Particle concentrations were measured using an electronic particle counter (Coulter Counter) at an appropriate size range for the algae and microspheres. Our results indicate that microspheres with or without surfactant had no effect on clearance rates of mussel compared to those of the controls. Further, our research suggests that the use of polystyrene microspheres in future experiments without initial washing does not affect the clearance rate of mussels.
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Density of Compatible Ligands on the Surface of Food Particles Modulates Sorting Efficiency in the Blue Mussel Mytilus edulis
The adhesion between food particles and mucus is a fundamental process in particle sorting in suspension-feeding bivalves that requires specific recognition. Interactions between carbohydrate-binding proteins (lectins) expressed on the feeding organs and carbohydrates present on microbial cell surface can provide this specificity. Microalga cell surface carbohydrates (MCSC) represent unique patterns that can be considered as species-specific fingerprints. In this study, sorting efficiencies in blue mussels Mytilus edulis fed with microalgae having modified MCSC and engineered microspheres coated with target carbohydrates was measured. The nature and quantities of surface carbohydrates required to trigger sorting in mussels was evaluated and the relationship between ligand quantities and sorting efficiency (SE) was determined. Mussels fed with Chlamydomonas which MCSC were blocked with ConA or PEA lectins (affinity to mannose and glucose) led to a significant decrease of the sorting efficiencies, not observed when the lectin UEA (affinity to fucose) was used. The ability of commercial lectins to inhibit sorting was not linear and a threshold was noted between 30 and 45 ug lectins per million algae cells. Further, mussels were fed with microspheres coated with neoglycoproteins. Results showed that glucose-BSA, but not fucose-BSA, has an effect on particle sorting in mussels, and 1.08 x 10 9 molecules of glucose per microspheres, corresponding to a density of 6.99 x 10 6 molecules of glucose per µm 2 , triggers particle selection. These findings support that selection of food particles by mussels rely on the strength of the bond between suspended particle and the mucosal layer that mediate sorting, and that these bonds depend on the quantity of compatible ligands on each particle.
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- Award ID(s):
- 1656753
- PAR ID:
- 10332425
- Date Published:
- Journal Name:
- Frontiers in Marine Science
- Volume:
- 9
- ISSN:
- 2296-7745
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Suspension-feeding mollusks (e.g., bivalves) play a key role in improving the water quality of coastal environments by filtering out suspended matter from the water column. Microplastics are becoming ubiquitous in the marine environment, so it is important to understand if these particles affect feeding processes of bivalves. Additionally, previous studies regarding the impact of microplastic on bivalve physiology have not independently tested for the effects of surfactants which are often added to commercially available plastic particles to prevent aggregation. We measured the clearance rate of mussels (Mytilus edulis) exposed to one type of microplastic and three common surfactants. Mussels were given a dose of microalgal food (1 x 104 cells/mL) and 10-m polystyrene spheres (Polybead; 1 x 104 beads/mL). Experimental treatments tested were washed microspheres and microspheres coated with each of the following surfactants at a concentration of 2mg/L: triton X-100, benzalkonium chloride, and sodium dodecyl sulfate. These surfactants are nonionic, cationic, and anionic, respectively. Control mussels were given a microalgal diet only (2 x 104 cells/mL). Each mussel was placed in an individual 1-L chamber and exposed to one of the aforementioned treatments. Water samples were taken at the start of the experiment (t=0) and then every 10 minutes for 30 minutes to determine clearance rates. Particle concentrations were measured using an electronic particle counter (Coulter Counter) at an appropriate size range for the algae and microspheres. Our results indicate that microspheres with or without surfactant had no effect on clearance rates of mussel compared to those of the controls. Further, our research suggests that the use of polystyrene microspheres in future experiments without initial washing does not affect the clearance rate of mussels.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/fmars.2022.882356
