Importance to Mussels of the Benthic Boundary Layer

Abstract

1984. Importance to mussels of the benthic boundary layer. Can. 1. Fish. Aquat. Sci. 41 : 1618-1625 We examined whether populations of the blue mussel Mytiius edulbs (Linnaeus, 1758) and horse mussel Modiolus modiolus (Linnaeus, 1758) could, by their feeding activities, deplete the sestonic food supply. The experiments were conducted in a 5-m-long by 56-cm-wide flume in which a turbulent boundary layer flow was created. The seston concentration was measured both as AT$ content and numbers of bacteria by acridline orange staining technique on separate subsamples of seawater. Sampling locations were at the flume inlet and at a point 3.6 m downstream (outlet). Four of the five replicated experiments with blue mussels had significant AHP-seston depletion but no reduction in bacterial numbers at the outlet sampling location. Of three replicated experiments with horse mussels, two had significant ATP-seston depletion and all three had significantly fewer bacterial numbers at the outlet sampling location. We consider that these results provide direct evidence in support of the hypothesis that seawater hydrodynamic factors may be critical in determining the food supply available to suspension-feeding animals. Our results confirm circurnstantia% evidence on this point obtained from field observations by previous investigators. Experimental verification of seston depletion is a necessary, but not sufficient, step in establishing that suspension-feeding animals may be food limited as required by the trophic group mutual exclusion hypothesis.Nous avons tent6 de determiner si les populations de moules bleues, Myfilus edudis (Linnaeus, 1758), et de rnodioles, Modiolus msdisius (Linnaeus, 1758), pouvaient, en se nourrisant, epuiser la rkserve de seston. Les experiences ont ete realisees dans uneenceinte de5 m dle long et56 cm de large dans lequel on a cree un courant turbulent de couche limitrophe. La concentration du seston dans differents 6chantilions d'eau de mer a kt6 6valuee en mesurant la teneur en A-BP et le nombre de bacterie au rnoyen d'une coloration a ['orange d'acridine. Les echantillons ont ete prelev6s a %'entree de Ifenceinte et A un point situCI h 3,6 rn en aval (sortie). Dans quatre des cinq essais realises avec les moules bleues, %a teneur du seston en ATP au point de prelevement situe era aval avait serieusement diminue, contrairernent au nombre de bacteries qui etait rest6 le meme. Dans deux des trois essais realises avec les rnodioles, on a obtenu une teneur en ATP nettement dirninuke, et dans les trois cas, le nombre de bacteries a la sortie de Ifenceinte etait beaucoup plus faible. Nous considerons que ces r6sultats appuient directement Ifhypothese selon laquelle la reserve de nourriture accessible aux anirnaux se nourrissant d'elernents en suspension est determinee de facon critique par des facteurs hydrodynamiques de I'eau de mer. Nos resultats confirment les suppositions circonstanciees formulees anterieurement a partir d'observations in situ par d'autres chercheurs. La verification experimentale est ...

Scale‐Dependent Feedback and Regular Spatial Patterns in Young Mussel Beds

“…This hypothesis concurs with an extensive body of literature reporting that depletion of the algae in lower water layers limits the growth of mussels in real (Frechette and Bourget 1985;Newell 1990;Muschenheim and Newell 1992;Frechette and Despland 1999;Dolmer 2000) and artificial conditions (Wildish and Kristmanson 1984;Widdows et al 2002). Moreover, mussels were found to generate local heterogeneity in the concentration of algae in the lower water layers, even on spatial scales of !10 m (Asmus et al 1992;L.…”

“…A significant body of literature exists that shows that, in soft-sediment or subtidal mussel beds, algal food availability limits intake by mussels (Wildish and Kristmanson 1984;Dolmer 2000;Widdows et al 2002) and mussel growth (Frechette and Bourget 1985;Page and Hubbard 1987;Newell 1990;Muschenheim and Newell 1992;Frechette and Despland 1999;Oie et al 2002). Dislodgment and predation depend strongly on local mussel density (Bertness and Grosholz 1985;Okamura 1986;Cote and Jelnikar 1999;Hunt andScheibling 2001, 2002) because nearby conspecifics are the main substrate for attachment on soft-bottom sediment.…”

“…Predation of algae by mussels on soft sediment occurs mostly in the lower water layer (Wildish and Kristmanson 1984;Muschenheim and Newell 1992). Predation is matched by influx of algae from upper water layers and by lateral transport of algae through tidal currents and, to a lesser extent, turbulent diffusion.…”

Native eelgrass Zostera marina controls growth and reproduction of an invasive mussel through food limitation

“…The expectation that mussels within eelgrass beds have less food is supported by observations of lower concentrations of chlorophyll a (chl a) in the feeding ambit of mussels inside eelgrass patches compared to in nearby unvegetated areas (Reusch & Williams 1999). Reduced water flow and local depletion of suspended particles has been implicated in food limitation of other suspensionfeeding organisms (Wildish & Kristmanson 1984, Fré-chette et al 1989, Butman et al 1994, and there is compelling indirect evidence that bivalve growth can be limited by food availability (Kautsky 1982, Peterson 1982, Bertness & Grosholz 1985, Fréchette & Bourget 1985, Peterson & Black 1987. This hypothesis has not, however, been tested directly in the field.…”

Evaluation of the Danish mussel fishery: suggestions for an ecosystem management approach

“…An increase in either factor will significantly increase the vertical transport of food to suspension-feeding benthic animals (Fréchette et al 1989;Butman et al 1994;Lenihan 1999). Several experiments conducted both in the field (Fréchette and Bourget 1985;Fréchette et al 1989;Dolmer 2000a, b) and in flumes (Wildish and Kristmanson 1984;Butman et al 1994) have shown that suspension-feeding animals, including blue mussels, are able to deplete seston from the near-bed layer. This indicates that at least some sections of a mussel bed may be food-limited and a change in near-bed mixing may therefore affect individual growth, especially in the downstream parts of mussel beds (Fréchette and Bourget 1985;Fréchette et al 1989;Clausen and Riisgård 1996).…”