Effects of algal concentration, bacterial size and water chemistry on the ingestion of natural bacteria by cladocerans

Journal of Plankton Research, 11, 1273–1295, 1989. The values of P/U⁰ (Table I) and fluid velocity used to calculatethe energy required for sieving (pp. 1289–1290) and severalequations (footnote b of Table I; p. 1290, lines 3–4)are incorrect. The corrected table appears below: Table I. Filter setule measurements (mean and within specimenstandard deviation) of the gnathobases for the cladocerans studied^aGnathobaseof trunklimb number. ^bP = 8µU₀/(b(1 – 21nt + 1/6(t²) - 1/144(t⁴))), whereP = pressure drop in dyn cm^–2, =3.1416, U₀ = fluid velocityin cm s^–1, b = distance between setule centres in cm,t = ( x setule diameter)/b and µ = 0.0101 dyn s^–1cm^–2. Formula from Jørgensen (1983). The text (p. 1289, line 19 to p. 1290, line 10) should read: organism. Using a similar argument, a 0.5 mm Ceriodaphnia witha filter area of 0.025 mm² (Ganf and Shiel, 1985) and pressuredrop P = 2757 dyn cm^–2 (with fluid velocity of 0.07 cms^–1) allocates only 2171 ergs h^–1 to filtrationof a total energy expenditure of 10⁴ ergs h^–1 filtrationenergy (ergs h^–1) = area (cm²) x pressure drop (dyn cm^–2)x 3600 (s h^–1) x 1/0.2 (efficiency of conversion of biochemicalinto mechanical work); total energy (ergs h^–1) = respiration(0.05 µl O₂ ind^–1 h^–1 consumed; Gophen, 1976)x conversion factor (2 x 10⁵ ergs µl^–1 O₂). Withan estimated 0.034 mm² in filter area, fluid velocity of 0.041cm s^–1 and respiration of 1.8 x 10⁴ ergs h^–1 (calculatedfrom Porter and McDonough, 1984), a 0.5 mm Bosmina uses <4%of its metabolism to overcome filter resistance. The velocities used in the original examples (0.4 cm s^–1for Ceriodaphnia, 0.2 cm s^–1 for Bosmina) were derivedfrom literature values of appendage beat rate and estimatesof the distance travelled by the appendages during each beatcycle. This approach unnecessarily assumes that all water movedpasses through the filter. In the new calculations, the flowacross the filter needed for food to be collected by sieving(0.07 cm s^–1 for Ceriodaphnia and 0.041 cm s^–1 forBosmina) was determined from the maximum clearance rate/filterarea. The amended energy expenditures, although higher, do notrefute the sieve model of particle collection.