Figure
5 . Relative contributions of different forms of carbon to the released
food carbon over the entire 36-h depuration at different food rations
(a ) and the allocation of the ingested food carbon of marine
medaka (b ). Data are the mean ± SD (n =3–5). The error bars
represent the standard deviations. DOC, dissolved organic carbon;
CO2, carbon dioxide; PC, particulate carbon. The food
rations are expressed as a percentage of the fish dry weight (DW). The
values in brackets in subfigure (b) indicate the means of the
above-noted ranges.
3.3 Release and turnover of fish body carbon
The body carbon of the fish was replaced and released at relatively high
rates. The K e was 0.053 d-1 at
the daily food ration of 4.3% fish DW, whereas the rate was
significantly increased (0.12 d-1) at the daily food
ration of 2.2% fish DW (ANCOVA, p < 0.05) (Figure 6a).
The
proportions of DOC, CO2, and PC for both daily food
rations did not show clear change trends with depuration time
(least-squares regression, p > 0.1) (Figure 6b, c).
For the entire 8-d depuration, the proportions of DOC,
CO2, and PC did not
vary significantly between the two daily food rations (Figure 7a).
DOC,
CO2, and PC accounted for 39%–42% (40.4% on
average), 40%–45% (42.6% on average), and 16%–18% (16.9% on
average) of the released body carbon, respectively (Figure 7b).
Figure
6 . Retention of 14C-labeled structural carbon in
marine medaka during the 8-d depuration (a ) and the relative
contribution of different forms of carbon to the released fish body
carbon at daily food rations of 2.2% (b ) and 4.3%
(c ) of the fish dry weight (DW). Data are the mean ± SD (n
=3–5). The error bars represent the standard deviations. DOC, dissolved
organic carbon; CO2, carbon dioxide; PC, particulate
carbon. Note the natural logarithm scale in subfigure (a )