First published online January 12, 2004
Journal of Experimental Biology 207, 645-653 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.00765
Water calcium concentration modifies whole-body calcium uptake in sea bream larvae during short-term adaptation to altered salinities
Pedro M. Guerreiro1,2,
Juan Fuentes1,
Gert Flik2,
Josep Rotllant1,
Deborah M. Power1 and
Adelino V. M. Canario1,*
1 Centre of Marine Sciences (CCMAR), University of Algarve, Campus de
Gambelas, 8005-139 Faro, Portugal
2 Department of Animal Physiology, University of Nijmegen, 6525 ED Nijmegen,
The Netherlands

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Fig. 1. (A) Relationship between whole-body calcium influx and wet body mass. (B)
The same relationship with calcium influx divided by body mass, referred to as
specific calcium influx. Indicated are the regression lines (middle lines) and
their 95% confidence limits, correlation coefficents (r0),
statistical significance levels (P) and number of fish used
(N).
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Fig. 2. Time-course of whole-body calcium influx rate in fish maintained at 100%SW
(filled circles) and in fish transferred to 50%SW (open circles) for a 16-h
period. Each point is the mean least squares adjusted for body mass
(1050 mg), and the vertical lines are their standard errors. Asterisks
represent statistically significant differences to 100%SW
(*P<0.01; **P<0.001) at a given
time.
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Fig. 3. Effect of salinity (filled bars) and of addition of calcium (bars with
diagonal lines) or sodium (bars with horizontal lines) on sea bream larvae
whole-body calcium influx after 8 h (A) or 24 h (B) exposure. At 10%SW and
25%SW, calcium and sodium were added to match levels at 100%SW. At 100%SW,
calcium levels were added to match those at 150%SW (see Materials and methods
and Table 1). Each bar
represents the mean least squares adjusted for body mass and respective
S.E.M. Identical letters indicate groups that do not differ
statistically at P=0.05. The daggers indicate 100% mortality; NA, not
tested.
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Fig. 4. Effect of salinity (filled bars) and of addition of calcium (bars with
diagonal lines) or sodium (bars with horizontal lines) on sea bream larvae
drinking rate after 8 h (A) and 24 h (B) exposure. See legend to
Fig. 3 for further details.
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Fig. 5. Effect of salinity and of addition of calcium or sodium on estimated sea
bream larvae intestinal (filled bars) and extra-intestinal (hatched bars)
calcium uptake after 8 h (A) or 24 h (B) exposure. Modification in calcium and
sodium in 10%SW, 25%SW and 100%SW is described in the legend to
Fig. 3. Asterisks indicate
statistically significant difference between intestinal and extra-intestinal
fluxes at P=0.05. Daggers indicate 100% mortality; NA, not
tested.
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Fig. 6. Relationship between adjusted means of whole-body (squares, broken line),
intestinal (circles, continuous line) and extra-intestinal (inverted
triangles, dotted line) calcium uptake and environmental calcium concentration
for the data from Fig. 5.
Regression lines are shown, and closed and open symbols indicate,
respectively, 8 h and 24 h after transfer from 100%SW to other experimental
salinities.
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© The Company of Biologists Ltd 2004