Table 1.
Carbon utilization in the different treatments at atmospheric pressure.
| Treatment | Cell abundance [×109 cells mL-1] | Cell biomass [μmol C mL-1]a | Stimulated net bacterial biomass yield [μmol C ml-1]b | C assimilation into biomass [% of added C]c | O2 uptake in 23 days [μmol O2 mL-1] | Net C respiration in 23 days [μmol C mL-1]d | Net C respired in 23 days [% of added C]e | Total C used in 23 days (respired + assimilated) [μmol mL-1]f | Total C used [% of added carbon]g | Bacterial growth efficiency [%]h | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| day0 | unfed | 1.4 ± 0.1 | 2.3 ± 0.1 | ||||||||
| CHI | 1.3 ± 0.1 | 2.1 ± 0.1 | |||||||||
| TWEI | 1.3 ± 0.0 | 2.1 ± 0.0 | |||||||||
| EHUX | 1.4 ± 0.1 | 2.3 ± 0.1 | |||||||||
| BCLA | 1.4 ± 0.0 | 2.3 ± 0.1 | |||||||||
| MARC | 1.4 ± 0.0 | 2.3 ± 0.0 | |||||||||
| day23 | unfed | 2.3 ± 0.2 | 3.9 ± 0.3 | n/a | n/a | 2.9 ± 0.1 | n/a | n/a | n/a | n/a | n/a |
| CHI | 4.0 ± 0.1 | 6.7 ± 0.2 | 2.8 ± 0.4 | 17.0 ± 2.3 | 6.1 ± 0.1 | 3.2 ± 0.1 | 18.7 ± 0.5 | 6.0 ± 0.4 | 36.0 ± 2.3 | 47.2 ± 3.3 | |
| TWEI | 2.7 ± 0.1 | 4.5 ± 0.1 | 0.7 ± 0.4 | 3.9 ± 1.0 | 4.9 ± 0.1 | 2.0 ± 0.1 | 11.9 ± 0.5 | 2.7 ± 0.1 | 16.0 ± 0.8 | 23.8 ± 4.6 | |
| EHUX | 2.8 ± 0.2 | 4.6 ± 0.3 | 0.6 ± 0.2 | 4.4 ± 2.5 | 4.7 ± 0.1 | 1.8 ± 0.1 | 10.6 ± 0.6 | 2.5 ± 0.3 | 15.3 ± 2.0 | 27.0 ± 13.7 | |
| BCLA | 2.6 ± 0.1 | 4.3 ± 0.1 | 0.4 ± 0.2 | 2.4 ± 0.9 | 4.7 ± 0.0 | 1.8 ± 0.0 | 10.3 ± 0.1 | 2.1 ± 0.2 | 12.7 ± 0.9 | 18.6 ± 5.5 | |
| MARC | 2.8 ± n/a | 4.6 ± n/a | 1.1 ± n/a | 6.5 ± n/a | 4.4 ± 0.0 | 1.5 ± 0.0 | 8.7 ± 0.2 | 2.5 ± n/a | 15.1 ± n/a | 42.8 ± n/a |
All values are calculated as carbon content or oxygen uptake per mL wet sediment. The total carbon added for the different detritus treatments was equivalent to 16.6 μmol carbon mL-1 sediment. Day 0: starting conditions (in situ community), unfed: control sediments after 23 days of incubation, carbon amendments: chitin (CHI), Thalassiosira weissflogii (TWEI), Emiliania huxleyi (EHUX), Bacillaria sp. (BCLA), Melosira arctica (MARC); C: carbon; n/a: not applicable.
aUsing a conversion factor of 1.67 fmol C per cell (Børsheim et al., 1990; Boetius and Lochte, 1996), representing an estimate of bacterial biomass; bbacterial biomass yield in carbon-amended treatments minus bacterial biomass yield in unfed control; cbiomass yield divided by carbon added; drespiration in carbon-amended treatments minus respiration in unfed control as derived from oxygen uptake, and assuming a conversion factor of 1; erespired carbon divided by carbon added; fsum of respired and assimilated carbon; gtotal carbon used divided by total carbon added; hbiomass yield divided by total carbon used (assimilated + respired).