This study was carried out at an inter-tidal site at Cape Rachado
(02°24′48N, 101°51′31E, Fig. 1) from April 2003 until April
2004. A small mangrove forest populated with Sonneratia and Rhizophora trees
was located nearby. Bacterial respiration ranged 0.818–3.208μM
O
$_2$
h
$^{-1}$
, and the amount of carbon
respired was 9.80–38.44μg C L
$^{-1}$
h
$^{-1}$
. Concurrent bacterial production during the
incubation was 1.23–3.28μg C L
$^{-1}$
h
$^{-1}$
. Using both these respiration and production values,
we calculated the bacterial growth efficiency, and it ranged 4.0–11.1%.
The low growth efficiency indicated the lower substrate quality here. However
adding nutrients did not significantly increase bacterial growth rates
(Student's t-test for matched pairs: t=1.883, df=2, p>0.10). In this study,
protists consumed 0.49–5.72×10
$^4$
bacterial cells
mL
$^{-1}$
h
$^{-1}$
or 22 ± 15% of
bacterial production. In carbon equivalents, grazing ranged 0.15–
1.81μg C L
$^{-1}$
h
$^{-1}$
. Annual
bacterial production at this site is 42.7 g C m
$^{-3}$
yr
$^{-1}$
, and carbon consumed by the bacteria was estimated
at 585 g C m
$^{-3}$
yr
$^{-1}$
. Of this, only
8 g C m
$^{-3}$
yr
$^{-1}$
was channeled onto
protists. These calculations showed that effectively only 1% of the carbon
consumed by bacteria was passed onto protists. The role of bacteria here was
essentially that of a remineralizer, and as a sink for carbon.
