FOOD INPUTS, UTILIZATION, CARBON FLOW AND ENERGETICS
337
Fig. 11.11. Model of reaction of sediment community to mass sedimentation events. Upper panel: reaction to moderate event in early spring;
lower panel: reaction to larger, later event. The amplitude of the response depends on the amount of flux of labile material. From Pfannkuche
et al. (1999).
June were somewhat higher than those in August
(Cahet et al., 1990).
K.L. Smith et al. (1998) were able, using the
deep-diving manned submersible Alvin, to sample
diffuse areas and patches of phytodetrital floc of
different size and texture for in situ incubation using
a core tube respirometer. They found that oxygen
consumption of diffuse floc was similar to that in
background sediment, but that discrete patches and
those enriched with Radiolaria had significantly higher
rates. Time-lapse camera monitoring showed distinct
detrital aggregates covered up to 4.9% of the sea
floor at their abyssal Station ‘M’ off California. These
contributed substantially to the supply of organic
carbon to the sediment community while apparently
producing a minimal impact on sediment community
oxygen consumption (0.34% of total annual SCOC at
Station ‘M’).
Overall, it must be concluded from these differing
patterns that particle quality is probably the key factor
in understanding temporal variability in the metabolic
and other activities of organisms living in abyssal
sediments (Witbaard et al., 2000).
The linings of irrigated burrows created by metazoans provide hot-spots for microbial and meiofaunal
activity (Aller, 1982), while burrows and depressions
filled with phytodetritus are rich in bacteria and meiofauna which might respond within days to concentrated
energy sources (J.Y. Aller and Aller, 1986). Incubations
of heterotrophic micro-organisms and Cyanobacteria at
in situ conditions showed a rate of activity that would
consume natural detritus lying on the sea bed within
two months (Lochte and Turley, 1988; Thiel et al.,
1988/89). Further work has demonstrated an important
response by barophilic bacteria (Turley and Lochte,
1990a). Respiration by these organisms colonizing
detrital aggregates on the sea floor is estimated to
contribute as much as 80% to the seasonal increase in
sediment community oxygen consumption measured in
situ (Pfannkuche, 1993).
337
Fig. 11.11. Model of reaction of sediment community to mass sedimentation events. Upper panel: reaction to moderate event in early spring;
lower panel: reaction to larger, later event. The amplitude of the response depends on the amount of flux of labile material. From Pfannkuche
et al. (1999).
June were somewhat higher than those in August
(Cahet et al., 1990).
K.L. Smith et al. (1998) were able, using the
deep-diving manned submersible Alvin, to sample
diffuse areas and patches of phytodetrital floc of
different size and texture for in situ incubation using
a core tube respirometer. They found that oxygen
consumption of diffuse floc was similar to that in
background sediment, but that discrete patches and
those enriched with Radiolaria had significantly higher
rates. Time-lapse camera monitoring showed distinct
detrital aggregates covered up to 4.9% of the sea
floor at their abyssal Station ‘M’ off California. These
contributed substantially to the supply of organic
carbon to the sediment community while apparently
producing a minimal impact on sediment community
oxygen consumption (0.34% of total annual SCOC at
Station ‘M’).
Overall, it must be concluded from these differing
patterns that particle quality is probably the key factor
in understanding temporal variability in the metabolic
and other activities of organisms living in abyssal
sediments (Witbaard et al., 2000).
The linings of irrigated burrows created by metazoans provide hot-spots for microbial and meiofaunal
activity (Aller, 1982), while burrows and depressions
filled with phytodetritus are rich in bacteria and meiofauna which might respond within days to concentrated
energy sources (J.Y. Aller and Aller, 1986). Incubations
of heterotrophic micro-organisms and Cyanobacteria at
in situ conditions showed a rate of activity that would
consume natural detritus lying on the sea bed within
two months (Lochte and Turley, 1988; Thiel et al.,
1988/89). Further work has demonstrated an important
response by barophilic bacteria (Turley and Lochte,
1990a). Respiration by these organisms colonizing
detrital aggregates on the sea floor is estimated to
contribute as much as 80% to the seasonal increase in
sediment community oxygen consumption measured in
situ (Pfannkuche, 1993).