In vivoEffects of Brown Tide on the Feeding Function of the Gill of the Northern Quahog Mercenaria mercenaria(Bivalvia: Veneridae)

Abstract

In vivo effects of brown tide on the feeding function of the gill of the northern quahog Mercenaria mercenaria (Bivalvia: Veneridae) Robbins AbstractThe in vivo response of adult northern quahogs, Mercenaria mercenaria, to Aureococcus anophagefferens (brown tide) at the level of the gill was determined using video-endoscopy. Feeding activity, particle-approach velocities, and ventral-groove-transport velocities were documented after the quahogs were exposed to Isochryis galbana (baseline observations) supplemented with either toxic or nontoxic A. anophagefferens at two bloom concentrations (8 × 10 5 or 2 × 10 6 cells ml -1 ). Externally, there was no evidence of adverse effects of brown tide on feeding, as siphons remained extended and dilated. Toxic brown tide at both concentrations elicited gill muscular contractions, intermittent cessation of water flow, and decreased particle loading within the pallial cavity. The 8 × 10 5 cell ml -1 toxic treatment had no significant effect on approach velocities or ventral-groove-transport velocities after 2 h, although timeaveraging showed significant reduction of the latter during the last 30 min of exposure. The higher concentration of toxic brown tide caused a significant decrease in these velocities after only 1 h. Nontoxic brown tide produced none of these effects. Thus, A. anophagefferens compromised quahog feeding by stimulating contractions of the branchial musculature and interfering with lateral and ventral groove ciliary beating. These effects were both timeand concentrationdependent and could be caused by either a dopaminergic or a serotonergic toxic factor.

Selective Ingestion and Egestion of Plastic Particles by the Blue Mussel (Mytilus edulis) and Eastern Oyster (Crassostrea virginica): Implications for Using Bivalves as Bioindicators of Microplastic Pollution

“…Prior to internal observations, a small portion of the ventral region of the shell of each oyster and mussel was trimmed to accommodate the optical insertion tube (OIT) of the endoscope and prevent damage to the tube when the animal adducted its valves. Shell material was carefully removed without damaging the underlying mantle, and animals were allowed to recover for 1 day before being examined. − Prior to endoscopic observation, each bivalve was placed in a 1-L aerated chamber filled with filtered seawater (ca. 21 °C), delivered several mL of microalgal food ( Tetraselmis sp.…”

Molecular Mechanism of Modified Clay Controlling the Brown Tide Organism Aureococcus anophagefferens Revealed by Transcriptome Analysis

“…As a typical blooming species, Aureococcus anophagefferens has formed brown tides since 1985 and is widely prevalent in the United States, South Africa, and China, damaging the aquatic environment and ruining the local aquaculture industry. − Gobler et al (2011) published the genome sequence of A. anophagefferens , which has facilitated further study on the transcriptional regulation of the species in HAB mitigation using MC. From 2012 to 2016, the MC method was effectively used to control A. anophagefferens blooms in the coastal regions of Qinhuangdao, China.…”

Ecosystem disruptive algal blooms of the brown tide species, Aureococcus anophagefferens and Aureoumbra lagunensis

“…Although a toxin has never been isolated from Aureococcus, there is evidence for toxic activity, most likely within the extracellular polysaccharide (EPS) sheath surrounding the cells (Sieburth et al, 1988). This putative toxin deters feeding in bivalves by stimulating contractions of the branchial muscles and interfering with lateral and ventral groove ciliary beating (Gainey and Shumway, 1991;Robbins et al, 2010). In addition, it has also been argued that Aureococcus may be a poor source of nutrition for zooplankton (Lonsdale et al, 1996;Caron et al, 2004) and some bivalve larvae (Padilla et al, 2006;Bricelj and MacQuarrie, 2007).…”