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Aquatic Sciences

, Volume 63, Issue 2, pp 123–149 | Cite as

Composition and transport of settling particles in Lake Zurich: relative importance of vertical and lateral pathways

  • Erich Wieland
  • Peter Lienemann
  • Silvia Bollhalder
  • Alfred Lück
  • Peter H. Santschi

Abstract:

Time- and space-dependent variations in the composition of settling particles were investigated along a longitudinal transect in Lower Lake Zurich. The study was carried out during summer stratification using a two-dimensional array of sediment traps deployed in the hypolimnion. Samples of the sedimentary material were analysed for total C and total N, P, Ca, Si, Al, Fe, Mn, Mg, Na, K, and the trace elements Zr, Sr, Rb, Ti, Ba, S, Pb and Zn. The elements can be classified according to their preferences in associating with a specific carrier phase. The fluxes and composition of trapped particles were found to vary seasonally with fluctuations in the main components (organic matter, calcium carbonate, biogenic silica, manganese and iron oxides, silicates) and spatially due to the following in-lake processes: 1) increasing vertical particle transport of biomass and mineralic material in the shoreward direction, 2) lateral sediment transport, which caused sediment accumulation rates to increase with depth, leading to sediment focusing, 3) episodic and patchy events of CaCO3 precipitation in the epilimnion followed by sedimentation and lateral dispersion, and 4) formation of a patchy nepheloid layer in the slightly denser bottom waters containing more fine-grained particles in suspension. Sediment focusing by lateral pathways caused by particle transport between the southern and the northern basin of Lower Lake Zurich gave rise to post-depositional in-lake redistribution of particle-bound contaminants.

Key words: Settling particle composition, sediment focusing, Lake Zurich. 

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Copyright information

© Birkhäuser Verlag, 2001

Authors and Affiliations

  • Erich Wieland
    • 1
  • Peter Lienemann
    • 2
  • Silvia Bollhalder
    • 3
  • Alfred Lück
    • 3
  • Peter H. Santschi
    • 4
  1. 1.Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland CH
  2. 2.Swiss Federal Laboratories for Materials Testing and Research (EMPA), CH-8600 Dübendorf, Switzerland CH
  3. 3.Swiss Federal Institute for Water Resources and Water Pollution Control (EAWAG), CH-8600 Dübendorf, Switzerland CH
  4. 4.Dept. of Oceanography, Texas A&M University, Galveston, TX 77551, USA US

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