Origins and microenvironments of bacteria mediating fecal pellet decomposition in the sea
Tóm tắt
The fecal pellets of zooplankton are thought to be major carriers of organic matter from surface to deeper waters of the oceans. As the pellets descend, they release soluble components, partially due to breakdown by associated microorganisms. Previous laboratory work of other investigators has suggested that the surface of a fecal pellet rapidly acquires bacteria, which increase in abundance until they and their protozoan consumers disrupt the pellet membrane, spilling contents into the water. In contrast, our field collections of fecal pellets from free-floating particle interceptor traps (from the “Vertex” project off Central California in 1980 and off Mexico in 1981), suggest that microbial decomposition probably is initiated in the sea from inside the fecal pellets. Transmission and scanning electron microscopy indicate that bacterial populations are most abundant in the interior of fecal pellets obtained from the sea, but that the same pellets will acquire the surface bacterial lawn typically observed in laboratory studies if maintained aboard ship. If the fecal pellets are decomposed from the inside, then the principal agents are enteric bacteria or ingested, digestion-resistant bacteria, or both. Such bacteria may differ metabolically from those that colonize the fecal pellet surfaces. Further-more, the abundance of healthy-appearing bacteria inside the pellets suggests that their metabolic activities may produce microhabitats of reduced oxygen tension that could differ considerably from that of the pellet exteriors. Decomposition in these semi-enclosed microenvironments may proceed in a manner not yet predicted by models that attribute decomposition to well-aerated, surface-dwelling bacterial populations on fecal pellets in the sea.
Tài liệu tham khảo
Alldredge, A. L.: Abandoned larvacean houses: a unique food source in the pelagic environment. Science, N.Y. 177, 885–887 (1972)
Bishop, J. K. B. and J. M. Edmond: A new large volume filtration system for the sampling of oceanic particulate matter. J. mar. Res. 34, 181–189 (1976)
Bishop, J. K. B., J. M. Edmond, D. R. Ketten, M. P. Bacon and W. B. Silker: The chemistry, biology, and vertical flux of particulate matter from the upper 400 m of the equatorial Atlantic Ocean. Deep-Sea Res. 24, 511–548 (1977)
Deming, J. W. and R. R. Colwell: Barophilic bacteria associated with deep-sea animals. BioSci 31, 507–511 (1981)
Deming, J. W., P. S. Tabor and R. R. Colwell: Barophilic growth of bacteria from intestinal tracts of deep-sea invertebrates. Microb. Ecol. 7, 85–94 (1981)
Dunbar, R. B. and W. H. Berger: Fecal pellet flux to modern bottom sediment of Santa Barbara Basin (Calfornia) based on sediment trapping. Bull. geol. Soc. Am. 92, 212–218 (1981)
Fournier, R. O.: Studies on pigmented microorganisms from aphotic marine environments. Limnol. Oceanogr. 15, 675–682 (1970)
Frankenberg, D., S. L. Coles and R. E. Johannes: The potential trophic significance of Callianassa major fecal pellets. Limnol. Oceanogr. 12, 113–120 (1967)
Honjo, S.: Coccoliths: production, transportation and sedimentation. Mar. Micropaleont. 1, 65–79 (1976)
Honjo, S.: Sedimentation of materials in the Sargasso Sea at a 5,367 m deep station. J. mar. Res. 36, 469–492 (1978)
Honjo, S.: Material fluxes and modes of sedimentation in the mesopelagic and bathypelagic zones. J. mar. Res. 38, 53–97 (1980)
Honjo, S. and M. R. Roman: Marine copepod fecal pellets: production, preservation, and sedimentation. J. mar. Res. 36, 45–57 (1978)
Jannasch, H. W.: Microbial turnover of organic matter in the deep sea. BioSci. 29, 228–232 (1979)
Johannes, R. E. and M. Satomi: Composition and nutritive value of fecal pellets of a marine crustacean. Limnol. Oceanogr. 11, 191–197 (1966)
Knauer, G. A. and J. H. Martin: Primary production and carbon-nitrogen fluxes in the upper 1500 m of the Northeast Pacific. Limnol. Oceanogr. 26, 181–186 (1981)
Knauer, G. A., J. H. Martin:and K. W. Bruland: Fluxes of particulate carbon, nitrogen, and phosphorus in the upper water column of the Northeast Pacific. Deep-Sea Res. 26, 97–108 (1979)
Lee, J. J.: A conceptual model of marine detrital decomposition and the organisms associated with the process. Adv. aquat. Microbiol. 2, 257–291 (1980)
Longhurst, A. R., C. J. Lorenzen and W. H. Thomas: The role of pelagic crabs in the grazing of phytoplankton off Baja California. Ecology 48, 190–200 (1967)
Malick, L. E. and R. B. Wilson: Evaluation of a modified technique for SEM examination of vertebrate specimens without evaporated metal layers. In: SEM/1975, pp 259–266. Ed. by O. Johari and I. Corvin. Chicago: Illinois Institue of Technology Research Insitute 1975
McCave, I. N.: Vertical flux of particles in the ocean. Deep-Sea Res. 22, 491–502 (1975)
Menzel, D. W.: Primary productivity, dissolved and particulate organic matter, and the sites of oxidation of organic matter. In: The sea, Vol. 5. pp 659–678. Ed. by E. D. Goldberg. New York: John Wiley & Sons 1974
Ogawa, K.: Primary participation of fecal bacteria in the formation of suspended organic matter in the sea. II. Floc formation by fecal bacteria isolated from marine animals. Bull. Jap. Soc. scient. Fish. 43, 1089–1096 (1977)
Ohwada, K., P. S. Tabor and R. R. Colwell: Species composition and barotolerance of gut microflora of deep-sea benthic macrofauna collected at various depths in the Atlantic Ocean. Appl. envirl Microbiol. 40, 746–755 (1980)
Parsons, T. R., M. Takahashi and B. Hargrave: Biological oceanographic processes, 332 pp. New York: Pergamon Press 1977
Pomeroy, L. R. and D. Deibel: Aggregation of organic matter by pelagic tunicates. Limnol. Oceanogr. 25, 643–652 (1980)
Reynolds, E. S.: The use of lead citrate at high pH as an electronopaque stain in electron microscopy. J. Cell Biol. 17, 208–212 (1963)
Sieburth, J. McN.: Sea microbes, 491 pp. New York: Oxford University Press 1979
Silver, N. W. and A. L. Alldredge: Bathypelagic marine snow: deep sea algal and detrital community. J. mar. Res. 39, 501–530 (1981)
Silver, M. W. and K. W. Bruland: Differential feeding and fecal pellet composition of salps and pteropods, and the possible origin of the deep-water flora and olive-green “cells”. Mar. Biol. 62, 263–273 (1981)
Silver, M. W., A. L. Shanks and J. D. Trent: Marine snow: microplankton habitat and source of small-scale patchiness in pelagic populations. Science, N.Y. 201, 371–373 (1978)
Small, L. F., S. W. Fowler and M. Y. Ünlü: Sinking rates of natural copepod fecal pellets. Mar. Biol. 51, 233–241 (1979)
Sochard, M. R., D. F. Wilson, B. Austin and R. R. Colwell: Bacteria associated with the surface and gut of marine copepods. Appl. envirl Microbiol. 37, 750–759 (1979)
Soutar, A., S. A. King, P. A. Crill, E. Duffin and K. W. Bruland: Monitoring the marine environment through sedimentation. Nature, Lond. 266, 136–139 (1977)
Spurr, A. E.: A low-viscosity epoxy-resin embedding medium for electron microscopy. J. Ultrastruct. Res. 26, 31–43 (1969)
Stanier, R. Y., E. A. Adelberg and J. L. Ingraham: The microbial world, 871 pp. Englewood Cliffs, New Jersey: Prentice-Hall 1976
Tate, M. W. and R. C. Clelland: Nonparametric and shortcut statistics, 171 pp. Danville, Illinois: Interstate Printers & Publishers 1957
Turner, J. T.: Microbial attachment to copepod fecal pellets and its possible significance. Trans Am. microsc. Soc. 98, 131–135 (1979)
Turner, J. T. and J. G. Ferrante: Zooplankton fecal pellets in aquatic ecosystems. BioSci. 29, 670–677 (1979)
Urrère, M. A. and G. A. Knauer: Zooplankton fecal pellet fluxes and vertical transport of particulate organic material in the pelagic environment. J. Plankton Res. 3, 369–387 (1981)
Wiebe, P. H., S. H. Boyd and C. Winget: Particulate matter sinking to the deep-sea floor at 2000 m in the Tongue of the Ocean, Bahamas, with a description of a new sediment trap. J. mar. Res. 34, 341–354 (1976)
Wilson, T. R. S.: Evidence for denitrification in aerobic pelagic sediments. Nature, Lond. 274, 354–356 (1978)