Examining effects of surfactants on particle clearance rate and capture efficiency of the blue mussel Mytilus edulis

M Rosa,Y Flores,K Sierra,B Torres,Je Ward

doi:10.3354/ab00735

Abstract

Suspension-feeding bivalve molluscs perform important ecological roles by coupling pelagic and benthic systems during their feeding activities. Particle capture, and thus feeding, is dependent on particle encounter and retention on the gill filaments, with several factors influencing this process. Over the past 30 yr, different types of synthetic microspheres have been used to examine aspects of particle capture and ingestion by bivalves. Critics of this work have posited that manufactured particles may contain surfactants, chemicals commonly used in manufacturing to reduce surface tension, that could produce spurious capture and ingestion rates. The goal of this work was to experimentally assess whether the presence of different types of surfactants on manufactured polystyrene particles can result in instantaneous effects on particle capture by the blue mussel Mytilus edulis. The effects of 3 different types of common surfactants (sodium dodecyl sulfate, benzalkonium chloride, Triton-X) on clearance rates (CR) and capture efficiencies (CE) were tested. Results indicated that none of the surfactant treatments had an effect on CR. Treatment with one of the surfactants (Triton-X) significantly lowered CE for 3 µm sized spheres compared to the control spheres (Milli-Q treated). None of the other tested surfactants significantly affected CE when compared to the control treatment. These data add to an understanding of particle handling by bivalves, and suggest that concentrations of surfactants found on commercially available microspheres used for experiments or found in the environment have little immediate effect on feeding processes.

Highlights

Suspension-feeding bivalve molluscs are a critical component of benthic food webs, mediating the distribution of organic materials, cycling nutrients, and contributing significantly to biodeposition of organic and inorganic matter (Smaal et al 2019)
Mussel clearance rates (CR) ranged from 58.7 ± 23.6 ml min−1 for mussels feeding on Tetraselmis chui to 74.6 ± 18.0 ml min−1 for mussels feeding on T. chui and microspheres treated with a saturating solution of benzalkonium chloride (BKc)
This study experimentally assessed the instantaneous effects of 3 common industrial surfactants on CR and capture efficiencies (CE) of the blue mussel Mytilus edulis

Summary

Introduction

Suspension-feeding bivalve molluscs are a critical component of benthic food webs, mediating the distribution of organic materials, cycling nutrients, and contributing significantly to biodeposition of organic and inorganic matter (Smaal et al 2019). Much of the basic research on mechanisms of particle capture and selection by suspension-feeding bivalves has relied on the use of synthetic polystyrene microspheres These particles are uniform in size and can be formulated with fluorescent or colored dyes and reactive functional groups for covalently binding different compounds (e.g. neoglycoproteins). These features, and the ease at which they can be enumerated, are ideal for studying effects of size, concentration, and surface properties on particle feeding by bivalve larvae and adults (e.g. Solow & Gallager 1990, Silverman et al 1995, Ward 1996, Yahel et al 2009, Rosa et al 2015, 2017). Microspheres have been used to examine clearance rates (CR) of several suspension-feeding taxa with no reported toxic effects (Sanders et al 1989), to our knowledge no research has experimentally assessed whether an adsorbed surfactant can affect instantaneous CR or capture efficiencies (CE) of a suspension-feeding bivalve

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