Feeding physiology of Cerastoderma edule in response to a wide range of seston concentrations

Abstract

The suspension-feeding activity of Cei-astoderrna edule (L ) was investigated in response to a wide range of experimental seston concentrations which approximated the changes in seston quality and quantity found in the natural environment over tidal cycles of sediment resuspension. The different seston concentrations were produced by adding increasing quantities of resuspended fine sediment to a relatively low and constant algal concentration (0.59 mg dry wt I-'). The total seston concentrations (total particulate matter) varied over a wide range from 1.6 to 570 mg l", and the organic fraction (particulate organic matter) between 0.62 and 79.8 mg 1-' The organic content of the diets decreased with the increasing seston concentration, from 38.8% at the lowest concentration to 14 % at the highest concentration. A significant negative relationship was found between clearance rate of C. edule and seston concentration, with very low values at 570 mg 1-' of total seston. Filtration rate increased with seston concentration from a minimum value of 2.67 mg h-' at the lowest concentration to a maximum of 84.0 mg h-' at a concentration of 300 mg I-'. Above 300 mg 1-' there was an abrupt decline in filtration rate. Pseudofaeces production started at a concentration of 4.8 mg 1 ', showing its highest values at around 300 mg I-' The organic content of pseudofaeces was significantly lower than the organic content of the seston, suggesting that C. edule is able to preferentially select organic particles for ingestion instead of inorganic particles. Selection efficiency was maintained at a high and constant level at seston concentrations between 4.8 and 97 mg 1-', declining at the highest seston concentrations with the lowest organic content. Thus the physiological sorting and selection mechanism appears to be very effective at seston concentrations below 100 mg 1-l, this ability declining abruptly at higher concentrations. Ingestion rate was constant in the lower range of seston concentration (1.6 to 34 mg 1-l), increased at concentrations around 250 mg I-', and declined abruptly at the higher food rations. Absorption efficiency appeared relatively independent of seston concentrations over a large range, but it was reduced at concentrations above 250 mg 1-' We found a very effective digestive mechanism to regulate absorption rate at seston concentrations between 1.6 and 250 mg I-' The results suggest that C. edule can compensate efficiently for a decrease in seston quality over a wide range of seston concentration (1.6 to 300 mg I-') by maintaining an effective preingestive mechanism of selection for organic particulate matter, as well as increasing filtration and rejection rates. As a consequence, this species is well adapted to living in turbid environments, such as intertidal mudflats, which are characterised by marked fluctuations in seston quality and quantity, caused by resuspension of fine sedirnents during periods of high current velocities on the flood or ebb tides.

Modelling of suspension-feeding and growth in the green-lipped mussel Perna canaliculus exposed to natural and experimental variations of seston availability in the Marlborough Sounds, New Zealand

“…A similar dependence of absorption efficiency upon the organic content of ingested particles has been observed in many other species of bivalve shellfish (e.g. Bricelj & Malouf 1984, Bayne , Navarro et al 1993, Barille et al 1997, Navarro & Widdows 1997. Hawkins et al 1998a, suggesting that efficiencies of absorption are primarily limited by digestive processes.…”

“…Falconer & Owens 1990, Haure 1996. To better understand how filterfeeders function under such turbid conditions, a growing body of work has studied responses to increasing concentrations of natural seston (Sornin et al, 1983, Deslous-Paoli et al 1987, Hawkins et al 1996, Soletchnik et al 1996, Barille et al 1997, Navarro & Widdows 1997. In the present paper, we 0.0 0.5 1.0 1.5 2.0 Chlorophyll a Fig.…”

“…Presumably, this decline in filtration rate reflected the ultimate overloading of filter-feeding mechanisms. Yet, in previous studies that worked at high seston concentrations, filtration declined above concentrations of about only 100 mg TPM 1-' in the oyster Crassostrea gigas (Sornin et al 1983, Deslous-Paoli et al 1987, Banlle et al 1997) and 300 mg TPM 1-' in the cockle Cerastoderrna edule (Navarro & Widdows 1997). Therefore, compared with these 2 species, the capacity for filtration was considerably greater in P. canaliculus.…”

Influence of biota on spatial and temporal variation in sediment erodability and material flux on a tidal flat (Westerschelde, The Netherlands)

“…Previous studies have shown that as the clearance rate by C. edule gradually declines in response to increasing SPM, the mass filtered and deposited as faeces and pseudofaeces increases with SPM, reaching a maximum at ca 200 mg SPM 1-' (Navarro & Widdows 1997). Consequently, as the SPM increases from low values in the spring/summer to high values in the autumnhinter period, due to the physical/biological interaction (i.e.…”

The Effect of Turbidity Concentration and Body Size on the Filtration Rate and Pseudofaeces Production of the Mud Clam Polymesoda erosa (Solander, 1786) (Bivalvia: Corbiculidae)

“…The FR of the clam significantly increased in turbidity conditions of up to 750 mg/L. This was a remarkable feat as compared to , and which could filter in turbidity concentrations ranging from 10 to 570 mg/L (Bayne 1993, Navarro & Widdows 1997, Rueda & Smaal 2002 The PP of showed increasing rate at higher TC. Morillo-Manalo and Del Norte-Campos (2010) stated that the production of pseudofaeces implies maximum energy gain for the bivalves during feeding.…”