The filtration apparatus of Cladocera: Filter mesh-sizes and their implications on food selectivity

Abstract

The filtering apparatus of eleven Cladoceran species was studied. The distances between the setulae, which act as filters, were measured. Among adult individuals, they vary from 0.2 μm in Diaphanosoma brachyurum to 4.7 μm in Sida crystallina. Species can be grouped according to the mesh-sizes, as "fine mesh filter-feeders": Diaphanosoma brachyurum, Ceriodaphnia quadrangula, Chydorus sphaericus, Daphnia cucullata and Daphnia magna; "medium mesh filter-feeders": Daphnia galeata, D. hyalina. D. pulicaria, Bosmina coregoni, and "coarse mesh filter-feeders": Holopedium gibberum and Sida crystallina. In Daphnia hyalina, the distances between setulae increase from 0.3-0.4 μm in small juveniles, to 0.8-2.0 μm in adults. In Daphnia magna, the mesh-size of the filter does not increase significantly with growth. There is good evidence that the relative abundance of the filter-feeding types varies with the trophic state of the lake. In oligotrophic lakes the "coarse mesh filter-feeders" usually dominate throughout the year. The seasonal succession of zooplankton species in eutrophic lakes can be interpreted as a succession of feeding types; during winter "coarse mesh filter-feeders" dominate, while "fine mesh filter-feeders" are most abundant during summer phytoplankton blooms. Our results support the hypothesis that the species composition of filter-feeding zooplankton is strongly influenced by the amount of suspended bacteria which are available as food only for filter-feeding species with fine meshes.

Daphnia versus copepod impact on summer phytoplankton: functional compensation at both trophic levels

“…The response of the phytoplankton species agrees with what is generally known abut the food spectra and feeding behaviour of filter-feeding cladocera and copepods (DeMott 1986(DeMott , 1988Geller and Müller 1981;Gliwicz 1980;Jürgens 1994). However, copepods and cladocerans show a much bigger overlap in food size spectra when fed by laboratory monocultures (Santer 1994; for a detailed discussion cf.…”

“…While it is commonplace to regard Daphnia as second trophic level and cyclopoid copepods as third trophic level organisms, the trophic level of calanoid copepods has become a matter of debate during the last years. In fact, both Daphnia and calanoid copepods are probably best characterised as omnivores with different, but widely overlapping food size spectra (Adrian and Schneider-Olt 1999;Burns and Schallenberg 1996;Geller and Müller 1981;Gliwicz 1980;Kleppel 1993;Sommer et al 2000;Sommer and Stibor 2002;Stoecker and Capuzzo 1990). In addition to size, copepod feeding selectivity is also determined by chemical food quality (DeMott 1986(DeMott , 1988) which might spare toxic or otherwise chemically unsuitable algae from being grazed, even if they are of the appropriate size.…”

Taxon-specific δ13C analysis of chitinous invertebrate remains in sediments from Strandsjön, Sweden

“…Bryozoa live predominantly as colonies attached to hard substrates and feed on suspended nanoplanktonic algae from the water column, but they cannot move through the water themselves (Kaminski 1984;Okamura and Hatton-Ellis 1995;Wood and Okamura 2005). Daphnia are mobile zooplankton feeding on fine particles in the water column that range between 0.5 and 30 lm in diameter and include phytoplankton and bacteria (Geller and Müller 1981). It can be assumed, therefore, that d 13 C of Daphnia and Bryozoa reflects the material they filter from the water column.…”

Limnological variations of a deep reservoir in periods with distinct rainfall patterns

“…(e.g. Geller andMüller, 1981, Lampert andSommer, 1997;Tillmanns et al, 2008;Sarnelle et al, 2010). Therefore, Daphnia and C. numidicus (also herbivorous) might have been strongly affected by the presence of the cyanobacterium ( Figure 5).…”