Feeding and Digestion in Bivalvia

Morton, Brian; Wilbur, Karl M.; Trueman, E. R.; Clarcke, M. R.

doi:10.1016/b978-0-12-751405-5.50010-5

Cited by 162 publications

(162 citation statements)

References 207 publications

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“…Surgery and dissection could destroy subtle hydrodynamic interactions between feeding structures and particles (Beninger et al 1992), eliminate the control animals have over muscle and cilia movement, alter the normal flow of water through the pallial cavity, damage delicate feeding structures, and stress the animals, causing structures to function abnormally. These problems, together with difficulties in observing pallial structures with a dissecting microscope through the small valve gape or through holes drilled in the shell, have led to an incomplete picture of the feeding process (MacGinitie 194 1;Morton 1983;Jorgensen 1990). Observations made under these conditions should be interpreted with caution.…”

Section: Resultsmentioning

confidence: 99%

Mechanisms of suspension feeding in bivalves: Resolution of current controversies by means of endoscopy

Ward

MacDonald

Thompson

et al. 1993

Limnology & Oceanography

128

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Controversy concerning the mechanism of suspension feeding in bivalves centers around whether particle capture and transport on the gills (ctenidia) is accomplished via mucociliary or hydrodynamic action. Evidence for and against these fundamentally different processes has been based on examinations of isolated feeding structures and dissected specimens, techniques that may produce artifactual data owing to the trauma associated with the procedures. In the present study, in vivo observations of the ctenidia of undisturbed bivalves, made with a fiber-optic endoscope and video image-analysis system, revealed that the two mechanisms are not mutually exclusive. Both mucociliary and hydrodynamic mechanisms function concurrently at different sites on the ctenidia, thereby minimizing particle loss and optimizing particle transport efficiency. The importance of mucus in the normal feeding process of bivalves is confirmed. These findings refute results of previous studies that used surgically invasive techniques and emphasize the importance of making observations on morphologically intact specimens.

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Section: Resultsmentioning

confidence: 99%

Mechanisms of suspension feeding in bivalves: Resolution of current controversies by means of endoscopy

Ward

MacDonald

Thompson

et al. 1993

Limnology & Oceanography

128

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“…62,63 Once ingested, the particles enter the stomach and the digestive tubules unobstructed and can be absorbed by the midgut gland cells. 64,65 In contrast to isopods, M. edulis showed microplastic aggregation in the gut and transfer of microparticles into the digestive tubules (hepatopancreas). 24,25 Moreover, microplastics smaller than about 10 μm were subsequently transferred into the circulatory system of the bivalve.…”

Section: ■ Discussionmentioning

confidence: 99%

Fate of Microplastics in the Marine Isopod Idotea emarginata

Hämer

Gutow

Köhler

et al. 2014

Environ. Sci. Technol.

259

105

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Plastic pollution is an emerging global threat for marine wildlife. Many species of birds, reptiles, and fishes are directly impaired by plastics as they can get entangled in ropes and drown or they can ingest plastic fragments which, in turn, may clog their stomachs and guts. Microplastics of less than 1 mm can be ingested by small invertebrates, but their fate in the digestive organs and their effects on the animals are yet not well understood. We embedded fluorescent microplastics in artificial agarose-based food and offered the food to marine isopods, Idotea emarginata. The isopods did not distinguish between food with and food without microplastics. Upon ingestion, the microplastics were present in the stomach and in the gut but not in the tubules of the midgut gland which is the principal organ of enzyme-secretion and nutrient resorption. The feces contained the same concentration of microplastics as the food which indicates that no accumulation of microplastics happens during the gut passage. Long-term bioassays of 6 weeks showed no distinct effects of continuous microplastic consumption on mortality, growth, and intermolt duration. I. emarginata are able to prevent intrusion of particles even smaller than 1 μm into the midgut gland which is facilitated by the complex structure of the stomach including a fine filter system. It separates the midgut gland tubules from the stomach and allows only the passage of fluids and chyme. Our results indicate that microplastics, as administered in the experiments, do not clog the digestive organs of isopods and do not have adverse effects on their life history parameters.

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“…Freshwater mollusc morphological feeding and digestive anatomy varies depending on the taxa but C. fluminea can be broadly grouped together with typical unionids [44]. When considering bioaccumulation in molluscs by filter feeding, efficiencies of particle detainment, ingestion and assimilation need to be accounted for due to removal of particles from suspension indiscriminately, creating difficulties for exposure modelling [44]. An advanced understanding of mechanisms responsible for bivalve bioaccumulation of pharmaceuticals is needed.…”

Section: (D) Bioaccumulation Of Human Pharmaceuticals By Various Aquamentioning

confidence: 99%

Bioaccumulation and trophic dilution of human pharmaceuticals across trophic positions of an effluent-dependent wadeable stream

Haddad

Luek

et al. 2014

Phil. Trans. R. Soc. B

131

118

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Though pharmaceuticals are increasingly observed in a variety of organisms from coastal and inland aquatic systems, trophic transfer of pharmaceuticals in aquatic food webs have not been reported. In this study, bioaccumulation of select pharmaceuticals was investigated in a lower order effluent-dependent stream in central Texas, USA, using isotope dilution liquid chromatography–tandem mass spectrometry (MS). A fish plasma model, initially developed from laboratory studies, was tested to examine observed versus predicted internal dose of select pharmaceuticals. Pharmaceuticals accumulated to higher concentrations in invertebrates relative to fish; elevated concentrations of the antidepressant sertraline and its primary metabolite desmethylsertraline were observed in the Asian clam, Corbicula fluminea , and two unionid mussel species. Trophic positions were determined from stable isotopes (δ 15 N and δ 13 C) collected by isotope ratio-MS; a Bayesian mixing model was then used to estimate diet contributions towards top fish predators. Because diphenhydramine and carbamazepine were the only target compounds detected in all species examined, trophic magnification factors (TMFs) were derived to evaluate potential trophic transfer of both compounds. TMFs for diphenhydramine (0.38) and carbamazepine (1.17) indicated neither compound experienced trophic magnification, which suggests that inhalational and not dietary exposure represented the primary route of uptake by fish in this effluent-dependent stream.

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Feeding and Digestion in Bivalvia

Cited by 162 publications

References 207 publications

Mechanisms of suspension feeding in bivalves: Resolution of current controversies by means of endoscopy

Mechanisms of suspension feeding in bivalves: Resolution of current controversies by means of endoscopy

Fate of Microplastics in the Marine Isopod Idotea emarginata

Bioaccumulation and trophic dilution of human pharmaceuticals across trophic positions of an effluent-dependent wadeable stream

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