Comparative study of water-processing in two ciliary filter-feeding polychaetes (Ditrupa arietina and Euchone papillosa) from two different habitats

Abstract

A comparative study of feeding rates and structures was made with the 2 ciliary filterfeeding polychaetes Ditrupa arietina and Euchone papillosa from the Mediterranean Sea (Gulf of Lions, France) and the Gullmarsfjord (Sweden), respectively. The feeding rate (clearance) was measured as the volume of water cleared of 6 µm diameter flagellate cells (Rhodomonas sp.) per unit time. Most experiments were conducted at algal concentrations equivalent to about 0.4 to 3.8 µg chlorophyll a l -1

Particle capture and processing mechanisms in Sabellaria alveolata (Polychaeta: Sabellariidae)

“…The characteristics and organisation of feeding organs of Sabellaria alveolata contrast with those described for pinnules in the sabellids Sabella penicillus (Riisgård & Ivarsson 1990) and Euchone papillosa (Riisgård et al 2002), or the serpulid Ditrupa arietina (Riisgård et al 2002). Sabellids and serpulids have a higher level of complexity in their feeding structures compared to sabellariids: they have lobes curved around on either side of the mouth and bear tentacles over almost 360°, which stand out stiffly at regular intervals.…”

“…Latero-frontal cilia are known to have an important role in deflecting particles onto the frontal ciliary band in bivalves (Silverman et al 1996) as well as in polychaetes (Riisgård et al 2002). In Sabellaria alveolata, particles deflected onto the frontal cilia remain on this tract and are transported toward the secondary and primary grooves.…”

“…Less information is available concerning ciliary filter-feeding polychaetes, despite their suspected functional role in trophic webs (Fauchald & Jumars 1979). Nevertheless, water processing, velocities and capture of particle have been studied in sabellids (Jørgensen et al 1984, Mayer 1994, 2000 and serpulids (Riisgård et al , 2002 by means of video observations and measurements of filtration rate and retention efficiencies. No data concerning the mechanisms of particle capture are available for sabellariids, although they are considered ciliary filter feeders and very close to sabellids and serpulids in terms of an evolutionary trend in feeding organs (Rouse & Fauchald 1997).…”

Feeding mechanism of the polychaete Sabellaria alveolata revisited: comment on Dubois et al. (2005)

“…The clearance rate per cm of ciliary band was determined by Riisgård et al (2002, their for Ditrupa arietina, while for Sabella pavonia 1.8 ml h -1 cm -1 was calculated based on data in Riisgård & Ivarsson (1990;see Riisgård et al 2002, their Table 5). According to Dubois et al (2005), the particle collecting system of an adult Sabellaria alveolata is represented by 250 tentacles extended 1 cm from the tube.…”

Feeding mechanism of the polychaete Sabellaria alveolata revisited: reply to Riisgård & Nielsen (2006)

“…They compared this value using that of active suspension-feeding serpulids and sabellids based on length-specific CR (per cm of ciliary band) multiplied by the estimated total length of ciliary band (presumably active) on the tentacular filaments of S. alveolata (500 cm), to obtain individual CR value (e.g. Riisgård et al 2002). Their calculation, which shows that CR should theoretically be 250 to 900 times higher for an active suspension feeder, disregards some important aspects of the S. alveolata feeding processes:…”