Chemical Composition, Size Distribution and Particle Morphology of Suspended Particulate Matter at DOMES Sites A, B, and C: Relationships with Local Sediment Composition
Detailed measurements of the concentration, composition, size, and morphology of suspended particulate matter (SPM) in the eastern equatorial Pacific Ocean were made during separate cruises in 1975 and 1976. SPM concentrations in the surface waters (0–300 m) were highly variable (~30 ± 18 µg/1) and primarily dependent on the concentration of biogenic material which accounted for > 90% of the total SPM. Mean Si/Al, K/Al, Ti/Al ratios were significantly higher than the corresponding values for the underlying sediments, indicating probable concentration of these elements in biogenic matter and other nonaluminosilicate phases. Mn/Al ratios however, were close to or even less than the sediment values.
Particle concentrations, mean size, and Si/Al, K/Al, Ti/Al, and Fe/Al ratios all decreased from the surface waters to the top of the bottom nepheloid layer (BNL), indicating progressive dissolution and a concomitant remineralization of associated elements. However, nonaluminosilicate phases still accounted for more than 40–70% of the Si, K, Ti, and Fe in the deep water zone. After deposition, most of this nonaluminosilicate phase is either transformed into authigenic smectites or dissolved and released back into the water column.
Within the BNL (approximately the bottom 400 m of the water column), concentration increases of Al, Si, K, Ti, Mn, and Fe averaged 201%, 74%, 46%, 78%, 200%, and 119%, respectively, greater than the overlying waters, whereas total SPM increased only 20–40%. Chemical mass-balance calculations suggest that this BNL concentration increase is due to resuspension of aluminosilicates and hydrogenous Mn from the ≤ 1 µm fraction of the local bottom sediments.
KeywordsBottom Sediment Suspended Particulate Matter Suspended Matter Particle Number Concentration Suspended Particulate Matter Concentration
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- Amos, A.F., Roels, O.A., and Paul, A.Z., (1976) Environmental baseline conditions in a manganese-nodule province in April–May 1975, Proc. Offshore Tech. Conf. p. 341–356.Google Scholar
- Anderson, J.J., (1979) Distribution of chemical properties in the water column at Sites A, B, and C, (this volume).Google Scholar
- Anderson, J.J., and Richards, F.R., (1977) Chemical and biochemical observations from the DOMES study area in the Equatorial North Pacific, Univ. of Wash., Dept. of Oceanography Special Report No. 79.Google Scholar
- Baker, E.T., and Piper, D.Z., (1976) Suspended particulate matter: collection by pressure filtration and elemental analysis by thin-film x-ray fluorescence, Deep-Sea Res. 23, 181–186.Google Scholar
- Betzer, P.R., Carder, K.L., and Eggimann, D.W., (1974) Light scattering and suspended particulate matter on a transect of the Atlantic Ocean at 11°N, In: Suspended Solids in Water (editor R.J. Gibbs ) p. 295–314, Plenum Press, New York.Google Scholar
- Betzer, P. R., and Pilson, M.E.Q., (1970) Concentrations of particulate iron in Atlantic open-ocean water, J. Mar. Res. 28, 251–267.Google Scholar
- Bischoff, J.L., Heath, G.R., and Leinen, M., (1979) Geochemistry of deep-sea sediments from the Pacific manganese nodule province: DOMES Sites A, B, and C., (this volume).Google Scholar
- Carder, K.L., Betzer, P.R., and Eggimann, D.W., (1974) Physical, chemical and optical measures of suspended particle concentration: Their intercomparison and application to the West African Shelf, In: Suspended Solids in Water (editor R.J. Gibbs ) p. 173–193, Plenum Press, New York.Google Scholar
- Edmond, J.M., (1974) On the dissolution of carbonate and silicate in the deep ocean, Deep-Sea Res. 21, 455–480.Google Scholar
- Eittreim, S., Gordon, A.L., Ewing, M., Thorndike, E.M., and Bruckhausen, P., (1972) The nepheloid layer and observed bottom currents in the Indian-Pacific Antarctic Sea, In: Studies in Physical Oceanography-A Tribute to George Wüst on His 80th Birthday (editor A.C. Gordon ) p. 19–35, Gordon and Breach, New York.Google Scholar
- El-Sayed, S.Z., and Taguchi, S., (1979) Spatial and seasonal variabilities in the phytoplankton standing crop and primary productivity in a manganese nodule province (tropical Pacific), (this volume).Google Scholar
- Ewing, M., and Connary, S.D., (1970) Nepheloid layer in the North Pacific, In: Geological Investigations of the North Pacific (editor J. Hays ), Geol. Soc. Amer. Mem. 126, 41–82.Google Scholar
- Hayes, S., (1979) Benthic current observations in the tropical North Pacific Ocean, (this volume).Google Scholar
- Hein, J.R., Yeh, H-W., and Alexander, E.R., (in press) Distribution, mineralogy, chemistry, and oxygen isotopes of clay minerals from the north equatorial Pacific manganese nodule belt, Clays and Clay Minerals.Google Scholar
- Honjo, S., (1977) Biogenic carbonate particles in the ocean: Do they dissolve in the water column? In: The Fate of Fossil Fuel CO2 in the Oceans (editors N.R. Andersen and A. Malahoff ), p. 269–294, Plenum Press, New York.Google Scholar
- Jerlov, N.G., (1976) Marine Optics, Elsevier, Amsterdam.Google Scholar
- Kido, K., and Nishimura, M., (1975) Silica in the sea-its forms and dissolution rate, Deep-Sea Res. 22, 323–338.Google Scholar
- McCave, I.N., (1975) Vertical flux of particles in the ocean, Deep-Sea Res. 22, 297–310.Google Scholar
- Oztergut, E., Anderson, G.C., Burns, R.E., Lavelle, J.W., and Swift, S.A., (in press) Deep Ocean Mining of Manganese Nodules in the North Pacific; Pre-Mining Environmental Conditions and Anticipated Mining Effects.Google Scholar
- Piper, D.Z., Cook, H.E., and Gardner, J.V., (1979) Litho-stratigraphy and acoustic stratigraphy of the equatorial North Pacific: DOMES Sites A, B, and C, (this volume).Google Scholar
- Richards, A.F., (1977) Geotechnical testing of U.S. Geological Survey cores collected from the pelagic nodule area, central northwest Pacific Ocean, U.S.G.S. Open File Report 77–778, 267–350.Google Scholar
- Sternberg, R.W., Baker, E.T., McManus, D.A., Smith, S., and Morrison, D.R., (1974) An integrating nephelometer for measuring particle concentrations in the deep sea, Deep-Sea Res. 21, 887–892.Google Scholar
- Sverdrup, H.U., Johnson, M.W., and Fleming, R.H., (1942) The Oceans, Prentice-Hall, New York.Google Scholar
- Toyota, Y., and Okabe, S., (1967) Vertical distribution of iron, aluminum, silicon and phosphorus in particulate matter collected in the western North Pacific, Indian and Antarctic Oceans, J. Oceanogr. Soc. Japan 25, 1–9.Google Scholar
- Wiebe, P.H., Boyd, S.H., and Winget, S., (1976) Particulate matter sinking to the deep-sea floor at 2,000 m in the Tongue of Ocean, Bahamas, with a description of a new sedimentation trap, J. Marine Res. 34, 341–354.Google Scholar
- Yoshida, K., Mao, H-L., and Horrer, D. L., (1953) Circulation in the upper mixed layer of the equatorial North Pacific, J. Marine Res. 12, 99–120.Google Scholar