Biogeochemical indicators as tools for assessing sediment quality/vulnerability in transitional aquatic ecosystems

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Abstract

  • 1.We review the major variables that can be used to monitor sediment characteristics and benthic processes in transitional water bodies with respect to ecological significance, cost/time demands, method consensus, and uncertainty of the current techniques.
  • 2.Most of the state variables, namely organic matter, total nitrogen and phosphorus contents, are easily determined at low monetary/time cost using standardized techniques. However, they are not sufficiently informative to be used as individual-specific indicators.
  • 3.The speciation analysis of nitrogen, phosphorus, iron and reduced sulphur provides much more precise information on the sedimentary buffering capacity. However, analytical techniques are cost/time expensive and often present some critical step, which biases their generalized application.
  • 4.A good understanding of sedimentary processes can also be achieved by measuring benthic fluxes and process rates, but analytical techniques are too expensive to be applied in conventional monitoring programmes.
  • 5.A tentative integrated index, based on a few low-cost simple measures of sediment characteristics (granulometry, organic matter, carbonates, reactive iron and acid volatile sulphides) is proposed, which, in parallel with the water retention time, could provide a rapid assessment of sediment vulnerability status.

Copyright © 2004 John Wiley & Sons, Ltd.

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