Figure 1.
Depth profiles of chlorophyll-a in control (C), control + food (CF), bioturbator (BT), bio-irrigator (BI) and physical mixing (PM) treatments.
Profiles differed significantly and significant results of pairwise tests of treatments within TRxD(epth) are indicated by the colour of the bars: black bars indicate higher and white bars lower chlorophyll-a values among pairs; grey bars indicate slices not detected as significantly different from the same depth slices in other treatments by pairwise tests. Significantly lowest values are marked with “*”. “x”: chl-a content in the 0–1 cm of BI treatment only higher than 0–1 cm of BT treatment. Error bars indicate SE.
Table 1.
Results from Permanova analysis for differences in chlorophyll-a content (µg g−1), total TO13C (mg m−2) within the sediment and nematode density (ind. 10 cm−2) amongst experimental treatments (TR) (control, control+food, bioturbator, bio-irrigator and physical mixing) and depth (D), based on a Euclidean resemblance matrix.
Figure 2.
Sediment TO13C distribution in control + food (CF), bioturbator (BT), bio-irrigator (BI) and physical mixing (PM) treatments.
Profiles differed significantly and significant results of pairwise tests of TR within TRxD are indicated by the colour of the bars (cf. Figure 1). Significantly lowest values are marked with “*”. Compare with the original addition of ±400 mg algal 13C to the surface of the microcosms at the start of the experiment. Error bars indicate SE.
Figure 3.
Maximum oxygen depth at the end of the experiment (upper) and averaged oxygen consumption of measurement on day 3 and 10 (lower) in control (C), control + food (CF), bioturbator (BT), bio-irrigator (BI) and physical mixing (PM) treatments.
Results of pairwise tests are indicated by the colour of the bars (cf. Figure 1). Significantly lowest values are marked with “*”. Error bars indicate SE.
Figure 4.
Depth profiles of nematode densities in control (C), control + food (CF), bioturbator (BT), bio-irrigator (BI) and physical mixing (PM) treatments.
Profiles differed significantly and significant results of pairwise tests of TR within TRxD are indicated by the colour of the bars (cf. Figure 1). Significantly lowest values are marked with “*”. Error bars indicate SE
Figure 5.
Specific uptake (Δδ13C) of labelled diatoms by ‘other nematodes’, Sabatieria and Richtersia and averaged TOC in the different depth layers in the control + food (CF), bioturbator (BT), bio-irrigator (BI) and physical mixing (PM) treatments.
Specific uptake differed among TR (PM> BI and BT) and among DxSp. For nematodes, the results of the pairwise tests of Sp within DxSp interaction are indicated by the colour of the bars (cf. Figure 1). Coarse striped bars indicate <3 replicates. Note different scaling of x-axes. Error bars indicate SE.
Table 2.
Results from Permanova analysis for differences in Δδ13C (‰) and total uptake Itotal (µg C m−2) amongst the experimental treatments (TR), replicates (Rep) nested in TR, depth layers (D) and nematode groups (Sp) and their interactions TRxD, TRxSp, DxSp, Rep(TR)xD, Rep(TR)xSp, Rep(TR)xDxSp, TRxDxSp and Error term, based on a Euclidean distance based resemblance matrix (df = 3,3,2,8,9,6,6,15,15,15,17,48 resp.).
Figure 6.
Total uptake (µg C m−2) of labelled diatoms by ‘other nematodes’, Sabatieria and Richtersia in the different depth layers.
Total uptake only differed among DxSp. The results of the pairwise tests of Sp within the DxSp interaction are indicated by the colour of the bars (cf. Figure 1). Significantly lowest values are marked with “*”. Error bars indicate SE.
Figure 7.
Mineralisation of the added diatom C in the control + food (CF), bioturbator (BT), bio-irrigator (BI) and physical mixing (PM) treatment by the nematode (, black) and macrobenthic (
, gray) compartments and due to respiration (
, light gray).
Only “Remaining” algal C (, white) differs significantly among treatments. Error bars not shown.