depths of less than 1 m into the framework; however, some
reef pore waters become anoxic within centimeters of the
framework surface (Falter and Sansone, 2000b).
Hydraulically driven transport of water into, through,
and out-of coral reef frameworks has long been hypothesized as the primary driver of framework diagenesis –
the transformation of skeletal materials into limestone
rock (Haberstroh and Sansone, 1999). It is proposed that
the water brings both oxygen and particulate organic matter into the interstitial pore-spaces to sustain carbon
metabolism (Huettel and Rusch, 2000). Coral reef frameworks are highly permeable, typically with hydraulic conductivities (K) ranging between 10 and 1,000 m day
À1
.
Consequently, ambient hydraulic pressure gradients
across coral reef frameworks do seem large enough to
drive the flow of interstitial water (Falter and Sansone,
2000a) and thus drive diagenesis in the manner postulated.
Wave-induced mixing is an important process controlling
the exchange of shallow pore-water with overlying water
(Falter and Sansone, 2000a). Thus, variations in the oxygen and pH structure of pore-waters within the top 2 m
of sediment are affected by a habitat hydrodynamics,
which is affected by its location on the reef and the direction of waves impinging on the reef. The deep anoxic
regions of the reef frameworks, beyond the effects of
wave-induced mixing, are high in methane and sulfate
(Sansone et al., 1990).
Summary
Ranges, means, and limits of carbon metabolism are summarized for coral reefs worldwide; zones and habitats of
carbon production and consumption are also described.
The underlying functional processes and parameterizations of those processes are discussed. At this time, however, there are gaps in knowledge, and it is particularly
noted that interactions with nutrients are not yet well
established.
Dissolved inorganic carbon (i.e., carbon dioxide gas,
bicarbonate, and carbonate ion) is removed from the water
column by autotrophs and fixed into organic (tissue and
photosynthate) and inorganic (calcium carbonate skeletons) compounds. Gross primary production and community respiration rates vary greatly in different habitats of
reefs, with much of the respiration of organic material
occurring within the organism or the habitat in which it
was produced. Net community production varies among
habitats. In classic reef zonation, carbon from the forereef is exported to the back-reef area as detritus and
dissolved organic carbon. Coral reef communities take
up suspended planktonic organic matter at rates that are
relatively low compared to their own primary production.
Sediments in coral reefs typically contain <1% organic
carbon, indicating little sequestration of organic carbon
into these systems. Dissolution of calcium carbonate
occurs naturally inside coral heads, in interior pore-spaces
of coral reef sediments, and from the erosion action of boring organisms. Globally, the surface area of coral reefs is
small and thus coral reefs have negligible effect on the
global carbon cycle.
Bibliography
Andrefouet, S., and Payri, C., 2000. Scaling-up carbon and carbonate metabolism of coral reefs using in-situ data and remote sensing. Coral Reefs, 19, 259–269.
Atkinson, M. J., and Cuet, P., 2009. Possible effects of ocean acidification on coral reef biogeochemistry: topics for research.
Marine Ecology Progress Series, 373, 249–256.
Atkinson, M. J., and Falter, J. L., 2003. Coral Reefs. In Black, K. P.,
and Shimmield, G. D. (eds.), Biogeochemistry of Marine Systems. Boca Raton, FL: CRC Press, pp. 40–64.
Atkinson, M. J., and Grigg, R. W., 1984. Model of a coral reef ecosystem: II. Gross and net benthic primary production at French
Frigate Shoals, Hawaii. Coral Reefs, 3, 13–22.
Atkinson, M. J., and Smith, S. V., 1983. C:N:P ratios of benthic
marine plants. Limnology and Oceanography, 28, 568–574.
Ayukai, T., 1995. Retention of phytoplankton and planktonic
microbes on coral reefs within the Great Barrier Reef, Australia.
Coral Reefs, 14, 141–147.
Boucher, G., Clavier, J., Hily, C., and Gattuso, J. P., 1998. Contributions of soft-bottoms to the community metabolism (primary
production and calcification) of a barrier reef flat (Moorea,
French Polynesia). Journal of Experimental Marine Biology
and Ecology, 225, 269–283.
Buddemeier, R. W., and Oberdorfer, J. A., 1988. Hydrogeology and
hydrodynamics of coral reef pore waters. 6th International Coral
Reef Symposium, Brisbane, Australia, 2, 485–490.
Carpenter, R. C., and Williams, S. L., 2007. Mass Transfer of photosynthesis on coral reef algal turfs. Marine Biology, 151,
435–450.
Crossland, C. J., Hatcher, B. G., and Smith, S. V., 1991. Role of
coral reefs in global ocean production. Coral Reefs, 10, 55–64.
Entsch, B., Boto, K. G., Sim, R. G., and Wellington, J. T., 1983.
Phosphorus and nitrogen in coral reef sediments. Limnology
and Oceanography, 28, 465–476.
Fabricius, K. E., Yahel, G., and Genin, A., 1998. In-situ depletion of
phytoplankton by an axoothanthallae soft coral. Limnology and
Oceanography, 43, 354–356.
Falter, J. L., and Sansone, F. J., 2000a. Hydraulic control of pore
water geochemistry within the oxic-suboxic zone of
a permeable sediment. Limnology and Oceanography, 45,
550–557.
Falter, J. L., and Sansone, F. J., 2000b. Shallow pore water sampling
in reef sediments. Coral Reefs, 19, 93–97.
Falter, J. L., Atkinson, M. J., and Langdon, C., 2001. Productionrespiration relationships at different time-scales within the Biosphere 2 coral reef biome. Limnology and Oceanography, 46,
1653–1660.
Ferrier-Pages, C., Gattuso, J. P., Cauwet, G., Jaubert, J., and
Allemand, D., 1998. Release of dissolved organic carbon and
nitrogen by the zooxanthellate coral Galaxea fascicularis.
Marine Ecology Progress Series, 172, 265–274.
Gattuso, J.-P., Pinchon, M., Delasalle, B., and Frankignoulle, M.,
1993. Community metabolism and air-sea CO2 fluxes in
a coral reef ecosystem (Moorea, French Polynesia). Marine Ecological Progress Series, 96, 259–267.
Gattuso, J. P., Pinchon, M., Delesalle, B., Canon, C., and
Frankignoulle, M., 1996. Carbon fluxes in coral reefs. I.
Lagrangian measurement of community metabolism and
resulting air-sea CO 2 disequilibrium. Marine Ecological Progress Series, 145, 109–121.
Gattuso, J. P., Frankignoulle, M., and Wollast, R., 1998. Carbon and
carbonate metabolism in coastal aquatic ecosystems. Annual
Review of Ecological Systems, 29, 405–434.
184
CARBON FLUXES OF CORAL REEFS
reef pore waters become anoxic within centimeters of the
framework surface (Falter and Sansone, 2000b).
Hydraulically driven transport of water into, through,
and out-of coral reef frameworks has long been hypothesized as the primary driver of framework diagenesis –
the transformation of skeletal materials into limestone
rock (Haberstroh and Sansone, 1999). It is proposed that
the water brings both oxygen and particulate organic matter into the interstitial pore-spaces to sustain carbon
metabolism (Huettel and Rusch, 2000). Coral reef frameworks are highly permeable, typically with hydraulic conductivities (K) ranging between 10 and 1,000 m day
À1
.
Consequently, ambient hydraulic pressure gradients
across coral reef frameworks do seem large enough to
drive the flow of interstitial water (Falter and Sansone,
2000a) and thus drive diagenesis in the manner postulated.
Wave-induced mixing is an important process controlling
the exchange of shallow pore-water with overlying water
(Falter and Sansone, 2000a). Thus, variations in the oxygen and pH structure of pore-waters within the top 2 m
of sediment are affected by a habitat hydrodynamics,
which is affected by its location on the reef and the direction of waves impinging on the reef. The deep anoxic
regions of the reef frameworks, beyond the effects of
wave-induced mixing, are high in methane and sulfate
(Sansone et al., 1990).
Summary
Ranges, means, and limits of carbon metabolism are summarized for coral reefs worldwide; zones and habitats of
carbon production and consumption are also described.
The underlying functional processes and parameterizations of those processes are discussed. At this time, however, there are gaps in knowledge, and it is particularly
noted that interactions with nutrients are not yet well
established.
Dissolved inorganic carbon (i.e., carbon dioxide gas,
bicarbonate, and carbonate ion) is removed from the water
column by autotrophs and fixed into organic (tissue and
photosynthate) and inorganic (calcium carbonate skeletons) compounds. Gross primary production and community respiration rates vary greatly in different habitats of
reefs, with much of the respiration of organic material
occurring within the organism or the habitat in which it
was produced. Net community production varies among
habitats. In classic reef zonation, carbon from the forereef is exported to the back-reef area as detritus and
dissolved organic carbon. Coral reef communities take
up suspended planktonic organic matter at rates that are
relatively low compared to their own primary production.
Sediments in coral reefs typically contain <1% organic
carbon, indicating little sequestration of organic carbon
into these systems. Dissolution of calcium carbonate
occurs naturally inside coral heads, in interior pore-spaces
of coral reef sediments, and from the erosion action of boring organisms. Globally, the surface area of coral reefs is
small and thus coral reefs have negligible effect on the
global carbon cycle.
Bibliography
Andrefouet, S., and Payri, C., 2000. Scaling-up carbon and carbonate metabolism of coral reefs using in-situ data and remote sensing. Coral Reefs, 19, 259–269.
Atkinson, M. J., and Cuet, P., 2009. Possible effects of ocean acidification on coral reef biogeochemistry: topics for research.
Marine Ecology Progress Series, 373, 249–256.
Atkinson, M. J., and Falter, J. L., 2003. Coral Reefs. In Black, K. P.,
and Shimmield, G. D. (eds.), Biogeochemistry of Marine Systems. Boca Raton, FL: CRC Press, pp. 40–64.
Atkinson, M. J., and Grigg, R. W., 1984. Model of a coral reef ecosystem: II. Gross and net benthic primary production at French
Frigate Shoals, Hawaii. Coral Reefs, 3, 13–22.
Atkinson, M. J., and Smith, S. V., 1983. C:N:P ratios of benthic
marine plants. Limnology and Oceanography, 28, 568–574.
Ayukai, T., 1995. Retention of phytoplankton and planktonic
microbes on coral reefs within the Great Barrier Reef, Australia.
Coral Reefs, 14, 141–147.
Boucher, G., Clavier, J., Hily, C., and Gattuso, J. P., 1998. Contributions of soft-bottoms to the community metabolism (primary
production and calcification) of a barrier reef flat (Moorea,
French Polynesia). Journal of Experimental Marine Biology
and Ecology, 225, 269–283.
Buddemeier, R. W., and Oberdorfer, J. A., 1988. Hydrogeology and
hydrodynamics of coral reef pore waters. 6th International Coral
Reef Symposium, Brisbane, Australia, 2, 485–490.
Carpenter, R. C., and Williams, S. L., 2007. Mass Transfer of photosynthesis on coral reef algal turfs. Marine Biology, 151,
435–450.
Crossland, C. J., Hatcher, B. G., and Smith, S. V., 1991. Role of
coral reefs in global ocean production. Coral Reefs, 10, 55–64.
Entsch, B., Boto, K. G., Sim, R. G., and Wellington, J. T., 1983.
Phosphorus and nitrogen in coral reef sediments. Limnology
and Oceanography, 28, 465–476.
Fabricius, K. E., Yahel, G., and Genin, A., 1998. In-situ depletion of
phytoplankton by an axoothanthallae soft coral. Limnology and
Oceanography, 43, 354–356.
Falter, J. L., and Sansone, F. J., 2000a. Hydraulic control of pore
water geochemistry within the oxic-suboxic zone of
a permeable sediment. Limnology and Oceanography, 45,
550–557.
Falter, J. L., and Sansone, F. J., 2000b. Shallow pore water sampling
in reef sediments. Coral Reefs, 19, 93–97.
Falter, J. L., Atkinson, M. J., and Langdon, C., 2001. Productionrespiration relationships at different time-scales within the Biosphere 2 coral reef biome. Limnology and Oceanography, 46,
1653–1660.
Ferrier-Pages, C., Gattuso, J. P., Cauwet, G., Jaubert, J., and
Allemand, D., 1998. Release of dissolved organic carbon and
nitrogen by the zooxanthellate coral Galaxea fascicularis.
Marine Ecology Progress Series, 172, 265–274.
Gattuso, J.-P., Pinchon, M., Delasalle, B., and Frankignoulle, M.,
1993. Community metabolism and air-sea CO2 fluxes in
a coral reef ecosystem (Moorea, French Polynesia). Marine Ecological Progress Series, 96, 259–267.
Gattuso, J. P., Pinchon, M., Delesalle, B., Canon, C., and
Frankignoulle, M., 1996. Carbon fluxes in coral reefs. I.
Lagrangian measurement of community metabolism and
resulting air-sea CO 2 disequilibrium. Marine Ecological Progress Series, 145, 109–121.
Gattuso, J. P., Frankignoulle, M., and Wollast, R., 1998. Carbon and
carbonate metabolism in coastal aquatic ecosystems. Annual
Review of Ecological Systems, 29, 405–434.
184
CARBON FLUXES OF CORAL REEFS