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Carbon cycling and POC turnover in the mesopelagic zone of the ocean: Insights from a simple model

By Thomas R. Anderson and Kam W. Tang


Carbon budgets of the mesopelagic zone are poorly constrained, highlighting our lack of understanding of the biota that inhabit this environment and their role in the cycling and sequestering of carbon in the deep ocean. A simple food web model of the mesopelagic zone is presented that traces the turnover of particulate organic carbon (POC), supplied as sinking detritus, through to its respiration by the biota via three pathways: colonization and solubilization of detritus by attached bacteria, production of free-living bacteria following losses of solubilization products during particle degradation, and consumption by detritivorous zooplankton. The relative consumption of detritus by attached bacteria was initially specified as 76%, with the remaining 24% by detritivores. Highlighting an asymmetry between consumption and respiration, the resulting predicted share of total respiration due to bacteria was 84.7%, with detritivores accounting for just 6.6% (with 6.5% and 2.2% by bacterivores and higher zooplankton, respectively). Bacteria thus dominated respiration and thereby acted as the principal sink for POC supplied to the mesopelagic zone, whereas zooplankton mainly recycled carbon back to the base of the food web as detritus or dissolved organic carbon rather than respiring it to CO2. Estimates of respiration are therefore not necessarily a reliable indicator of the relative roles of bacteria and zooplankton in consuming and processing POC in the mesopelagic zone of the ocean. The work highlighted a number of major unknowns, including how little we know in general about the dynamics and metabolic budgets of bacteria and zooplankton that inhabit the mesopelagic zone and, specifically, the degree to which the solubilized products of enzymatic hydrolysis of POC by attached bacteria are lost to the surrounding water, the magnitude and factors responsible for bacterial growth efficiency, the role of microbes in the nutrition of detritivores, and the recycling processes by which zooplankton return what they consume to the food web as detritus and dissolved organic matter

Topics: GC, QH301
Year: 2010
OAI identifier: oai:eprints.soton.ac.uk:160657
Provided by: e-Prints Soton

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  1. (2002). A model for the distribution of particle flux in the midwater column controlled by subsurface biotic interactions. doi
  2. (1998). A predictive model of bacterial foraging by means of freely released extracellular enzymes. doi
  3. (2001). A steady state model of particulate organic carbon flux below the mixed layer and application to the Joint Global Ocean Flux Study. doi
  4. (2004). A vertical model of particle size distributions and fluxes in the midwater column that includes biological and physical processes-Part I: Model formulation. doi
  5. (2004). A vertical model of particle size distributions and fluxes in the midwater column that includes biological and physical processes-Part II: Application to a three year survey in the NW Mediterranean Sea. doi
  6. (2005). Analyzing the trophic link between the mesopelagic microbial loop and zooplankton from observed depth profiles of bacteria and protozoa. doi
  7. (1978). Assimilation of particulate organic carbon by estuarine and coastal copepods. doi
  8. (1998). Bacterial colonization and ectoenzymatic activity in phytoplankton-derived model particles: Cleavage of peptides and uptake of amino acids. doi
  9. (2003). Bacterial colonization of particles: Growth and interactions. doi
  10. (1993). Bacterial distributions and production in the northwestern Indian Ocean and Gulf of Oman, doi
  11. (2000). Bacterial growth and grazing on diatom aggregates: Respiratory carbon turnover as a function of aggregate size and sinking velocity. doi
  12. (1998). Bacterial growth efficiency in natural aquatic systems. doi
  13. (1995). Bacterial mediation of carbon fluxes during a diatom bloom in a mesocosm. doi
  14. (2000). Bacterial production and growth efficiencies: direct measurements on riverine aggregates. doi
  15. (1990). Bacterial production and growth rate estimation from [3H] thymidine incorporation for attached and free-living bacteria in aquatic systems. doi
  16. (2008). Bacterial vs. zooplankton control of sinking particle flux in the ocean’s twilight zone. doi
  17. (2001). Basin-scale geographic patterns of bacterioplankton biomass and production in the subarctic Pacific, July-September
  18. (2005). Benthic life in the pelagic: Aggregate encounter and degradation rates by pelagic harpacticoid copepods. doi
  19. (1994). Biogeochemical significance of attached and freeliving bacteria and the flux of particles doi
  20. (1999). Breakdown and microbial uptake of marine viruses and other lysis products. doi
  21. (2004). C and N gross growth efficiencies of copepod egg production studied using a Dynamic Energy Budget model. doi
  22. (1984). Carbon and nitrogen budget of the calanoid copepod Temora stylifera: effect of concentration and composition of food. doi
  23. (1980). Carbon budget of a marine phytoplanktonherbivore system with carbon-14 as a tracer. doi
  24. (1989). Closing the microbial loop: dissolved carbon pathway to heterotrophic bacteria from incomplete ingestion, digestion and absorption in animals. doi
  25. (2007). Comparison of cell-specific activity between free-living and attached bacteria using isolates and natural assemblages. doi
  26. (2000). Comparison of growth efficiencies of protozoa growing on bacteria deposited on surfaces in suspension. doi
  27. (1992). Comparison of the chemical composition of particulate material and copepod faecal pellets at stations off the coast of Labrador and in the Gulf of St. doi
  28. (2003). Consumer-resource stoichiometry in detritus-based streams. doi
  29. (2005). Contribution of Archaea to total prokaryotic production in the deep Atlantic Ocean. doi
  30. (2005). Coprophage and coprorhyexy in the copepods Acartia tonsa and Temora longicornis: clearance rates and feeding behaviour. doi
  31. (2007). Coprorhexy, coprophagy, and coprochaly in the copepods Calanus helgolandicus, Pseudocalanus elongatus, and Oithona similis. doi
  32. (2004). Deep pelagic biology. doi
  33. (1995). Diet of copepod (Scopalatum vorax) associated with mesopelagic detritus (giant larvacean houses) in doi
  34. (2002). Dissolved organic carbon support of respiration in the dark ocean. doi
  35. (2006). Does excess carbon affect respiration of the rotifer Brachionus calyciflorus Pallas? doi
  36. (1988). Downward flux of particulate organic matter in the ocean: A particle decomposition paradox. doi
  37. (2003). Dynamics of microbial communities on marine snow aggregates: Colonization, growth, detachment, and grazing mortality of attached bacteria. doi
  38. (1982). Ecology of heterotrophic microflagellates. doi
  39. (2007). Effects of starvation on aggregate colonization and motility of marine bacteria. doi
  40. (2008). Excess carbon in aquatic organisms and ecosystems: Physiological, ecological, and evolutionary implications. doi
  41. (2003). Fate of diatom carbon and trace elements by the grazing of a marine copepod. doi
  42. (1993). Fate of particle-bound bacteria ingested by Calanus pacificus. doi
  43. (1998). Feeding by the euphausiid Euphasia pacifica and the copepod Calanus pacificus on marine snow. doi
  44. (2002). Feeding, respiration and egg production rates of copepods during austral spring in the Indian sector of the Antarctic Ocean: role of the zooplankton community in carbon transformation. doi
  45. (1987). Grazing of attached bacteria by heterotrophic microflagellates. doi
  46. (2002). Grazing rates of bacterivorous protists inhabiting diverse marine planktonic microenvironments. doi
  47. (1997). Gross growth efficiencies of protozoan and metazoan zooplankton and their dependence on food concentration, predator-prey weight ratio, and taxonomic group. doi
  48. (2003). How Daphnia copes with excess carbon in its food. Oecologia (Berlin) doi
  49. (2002). Influence of two different green algal diets on specific dynamic action and incorporation of carbon into biochemical fractions in the copepod Acartia tonsa. doi
  50. (1992). Intensive hydrolytic activity on marine aggregates and implications for rapid particle dissolution. doi
  51. (2006). Interactions between marine snow and heterotrophic bacteria: Aggregate formation and microbial dynamics. doi
  52. (1988). Kinetics and energetic of growth of the marine choanoflagellate Stephanoeca diplocostata. doi
  53. (1978). Lurkers of the Deep.
  54. (2003). Lysogeny and virus-induced mortality of bacterioplankton in surface, deep, and anoxic marine waters. doi
  55. (1988). Major role of bacteria in biogeochemical fluxes in the ocean’s interior. doi
  56. (2001). Marine snow, organic solute plumes, and optimal chemosensory behavior of bacteria. doi
  57. (2002). Mechanisms and rates of bacterial colonization of sinking aggregates. doi
  58. (1997). Mesozooplankton associations with medium to large marine snow aggregates in the northern Gulf of Mexico. doi
  59. (2005). Metabolic stoichiometry and the fate of excess carbon and nutrients in consumers. doi
  60. (1988). Microbial aggregation and degradation of phytoplankton-derived detritus doi
  61. (2001). Microbial degradation of organic carbon and nitrogen on diatom aggregates. doi
  62. (2001). Microbial loop carbon cycling in ocean environments studied using a simply steady-state model. doi
  63. (1994). Midwater zooplankton communities on pelagic detritus (giant larvacean houses) in doi
  64. (2002). Modelling particle transformations and the downward organic carbon flux in the NE Atlantic Ocean. Progress in doi
  65. (1990). New views on the degradation and disposition of organic particles as collected by sediment traps in the open sea. doi
  66. (1985). Ocean carbon pumps: Analysis of relative strengths and efficiencies in ocean-driven atmospheric CO2 changes. doi
  67. (1994). Organic content and bacterial metabolism in amorphous aggregations of the northern Adriatic Sea. doi
  68. (2004). Particle-associated flagellates: swimming patterns, colonization rates, and grazing on attached bacteria. doi
  69. (1999). Particulate and dissolved organic carbon production by the heterotrophic nanoflagellate Pteridomonas danica Patterson and Fenchel. doi
  70. (1999). Phagotrophic mechanisms and prey selection in freeliving dinoflagellates. doi
  71. (1993). Phylogenetic diversity of aggregateattached vs. free-living marine bacterial assemblages. doi
  72. (1997). Planktonic grazers are a potentially important source of marine dissolved organic carbon. doi
  73. (1987). Primary production, new production and vertical flux in the eastern Pacific Ocean. doi
  74. (1984). Primary productivity and particulate fluxes on a transect at the equator at 153°W in the Pacific Ocean. doi
  75. (2003). Production of DOC by Calanus finmarchicus, C. glacialis and C. hyperboreus through sloppy feeding and leakage from fecal pellets. doi
  76. (2006). Quantifying archaeal community autotrophy in the mesopelagic ocean using natural radiocarbon. doi
  77. (2002). Regeneration of dissolved organic matter by viral lysis in marine microbial communities. doi
  78. (2008). Regulation of aquatic microbial processes: the ‘microbial loop’ of the sunlit surface waters and the dark ocean dissected. doi
  79. (1994). Relating C:N ratios in zooplankton food and faecal pellets using a biochemical model. doi
  80. (1985). Relative feeding rates on free and particlebased bacteria by freshwater macrozooplankton. doi
  81. (1992). Release of macromolecular organic complexes by heterotrophic marine flagellates. doi
  82. (2005). Role of algal aggregation in vertical carbon export during SOIREE and in other low biomass environments. doi
  83. (1984). Role of bacteria in copepod fecal pellet decomposition: colonization, growth rates and mineralization.
  84. (1986). Role of large particles in the transport of elements and organic compounds through the oceanic water column. doi
  85. (2008). Selective feeding behaviour of key freeliving protists: avenues for continued study. doi
  86. (1995). Significance of viruses versus heterotrophic nanoflagellates for controlling bacterial abundance in the northern Adriatic Sea. doi
  87. (1988). Simultaneous measurement of the effect of food concentration on assimilation and respiration in Daphnia magna Straus. doi
  88. (2000). Spatial and temporal variations in chitinolytic gene expression and bacterial biomass production during chitin degradation. doi
  89. (1997). Spatially explicit simulations of a microbial food web. doi
  90. (1983). Starvation-survival physiological studies of a marine Pseudomonas sp.
  91. (2004). Stoichiometry: linking elements to biochemicals. doi
  92. (2002). The abundance, vertical flux, and still-water and apparent sinking rates of marine snow in a shallow coastal water column. doi
  93. (2007). The fate of discarded appendicularian houses: degradation by the copepod, Microsetella norvegica, and other agents. doi
  94. (2008). The microbial loop – 25 years later. doi
  95. (1976). The role of bacteria in the nutrition of aquatic detritivores. doi
  96. (1981). The survival of marine bacteria under starvation conditions. doi
  97. (1990). The vertical flux of metazoans (holoplankton, meiofauna, and larval invertebrates) due to their association with marine snow. doi
  98. (2006). Threshold elemental ratios of carbon and phosphorus in aquatic consumers. doi
  99. (2008). Towards a better understanding of microbial carbon flux in the sea. doi
  100. (1999). Transformations of biogenic particulates from the pelagic to the deep ocean realm. doi
  101. (2005). Ubiquity and diversity if ammonia-oxidizing archaea in water columns and sediments of the ocean. doi
  102. (1987). VERTEX: Carbon cycling in the northeast Pacific. doi
  103. (2006). Vertical flux and degradation orates of copepod fecal pellets in a zooplankton community dominated by small copepods. doi
  104. (1995). Viruses and protists cause similar bacterial mortality in coastal seawater. doi
  105. (1991). What happens to zooplankton fecal pellets? Implications for material flux. doi

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