Marine Biology

, Volume 137, Issue 4, pp 613–622

Effects of simulated deposition of dredged material on structure of nematode assemblages – the role of contamination

  • M. Schratzberger
  • H. L. Rees
  • S. E. Boyd

DOI: 10.1007/s002270000386

Cite this article as:
Schratzberger, M., Rees, H. & Boyd, S. Marine Biology (2000) 137: 613. doi:10.1007/s002270000386

Abstract

 Certain criteria must be satisfied before a licence for the deposition of dredged material at sea in UK waters is issued. These relate to the chemical quality of the material, the quantity to be disposed of, its nature and origin, and its predicted impacts at the disposal site. Although chemical analyses of dredgings provide an indication of the relative degrees of contamination, they do not provide a measure of any resultant biological effects. A laboratory experiment was therefore designed to investigate the effects of the degree of contamination and the role of burial associated with the deposition of dredged material on the meiofauna. Estuarine nematode assemblages were exposed to the simulated deposition of uncontaminated, oxic intertidal mud and anoxic sediments from the Mersey and the Tees estuaries, both of which were contaminated with heavy metals. The sediments, which differed little in terms of grain size, were deposited in two different frequencies. Nematodes showed a clear species-specific response to the experimental treatments, depending on the frequency of deposition and the chemical quality of the deposited material (e.g. metal and oxygen concentrations). The response of nematode assemblages was mainly determined by the deposition frequency rather than the type of sediment or the degree of contamination. The deposition of sediment in one large dose at the beginning of the experiment caused more severe changes in assemblage structure than the same quantity deposited in several smaller doses. Although lower than in uncontaminated mud, relatively high migration and survival rates in the contaminated high-frequency treatments were observed. This may have been due to reduced bioavailability of metals and the tolerance of estuarine nematodes to both metal contamination and the deposition of small sediment volumes at regular intervals. The observed trends demonstrate the potential of small-scale laboratory experiments for testing the quality of contaminated dredged material at the licensing stage, i.e. prior to the issue of a disposal licence.

Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • M. Schratzberger
    • 1
  • H. L. Rees
    • 2
  • S. E. Boyd
    • 2
  1. 1.University of Wales Bangor, School of Ocean Sciences, Menai Bridge, Gwynedd LL59 5EY, North Wales, Great BritainGB
  2. 2.The Centre for Environment, Fisheries and Aquaculture Science, Burnham Laboratory, Remembrance Avenue, Burnham-on-Crouch, Essex CM0 8HA, England Fax: 0044 (0) 1621 784989 e-mail: m.schratzberger@cefas.co.ukGB