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Defining ecological reference conditions in naturally stressed environments - How difficult is it?
Silvia Hess1, Elisabeth Alve1, Thorbjørn J Andersen2
1Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316, Oslo, Norway.
Marine Environmental Research
|March 17, 2020
Summary
Foraminifera biomonitoring links current ecological status to past conditions, establishing crucial reference points in stressed transitional waters. This method helps overcome challenges in assessing estuarine environmental quality.
Area of Science:
- Marine Ecology
- Paleoceanography
- Environmental Science
Background:
- Determining reference conditions in transitional waters and oxygen-depleted habitats is challenging.
- Naturally stressed environments complicate the assessment of Ecological Quality Status (EcoQS).
- The Estuarine Quality Paradox highlights difficulties in estuarine environmental quality assessment.
Purpose of the Study:
- To demonstrate how foraminifera can link present-day EcoQS to historical EcoQS.
- To bridge the knowledge gap in determining reference conditions for stressed aquatic environments.
- To illustrate a retrospective foraminiferal biomonitoring method for detecting environmental perturbations.
Main Methods:
- Analysis of foraminifera in sediment cores from Horten Inner Harbor, Norway.
- Geochemical analysis of oldest deposits to establish pre-industrial background concentrations.
- Application of a conceptual model for retrospective foraminiferal biomonitoring.
Main Results:
- Foraminifera successfully linked present-day EcoQS to historical EcoQS.
- Geochemical data indicated stable, good to high status conditions from approximately 1600 to 1800.
- The study established biologically defined reference conditions based on un-impacted historical organisms.
Conclusions:
- Foraminifera serve as effective bioindicators for retrospective environmental quality assessment.
- Retrospective foraminiferal biomonitoring is valuable for understanding long-term ecological changes in estuaries.
- The method aids in overcoming the Estuarine Quality Paradox by defining historical reference states.
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