Background and aim of the research:
Sea bottom trawling activities are intense in many coastal regions. The heavy gears used (e.g., dredges) physically disturb the benthic environment and alter its community structure. Impacts include the resuspension of fine-grained material and potentially contaminants, reduced community diversity, and altered faunal composition. The intensity and frequency of disturbance are key factors in determining trawling impacts and recovery times. As part of the fish population monitoring programme in the inner Oslofjord, an area in the Vestfjord is regularly trawled each year in late summer.
The MSc project will focus on the analysis of living benthic foraminiferal assemblages in this area. The project will include collecting short sediment cores along a transect that crosses the dredged area (before dredging, directly after, and 3, 6, and 9 months post-dredging) to analyse the response of the benthic foraminiferal community. At each sampling event, sediment samples will be collected in parallel for geochemical and trace metal analyses. Existing knowledge of faunal composition from surrounding areas will serve as a baseline for comparison during the recolonisation of the disturbed habitat. Changes in the benthic habitat might lead to shifts in abundance, diversity, microhabitat preferences, or faunal composition.
Main investigation questions to address:
- How severely is the benthic fauna affected by the physical disturbance of the area? (Lateral and horizontal).
- How quickly is the recolonisation process progressing?
- Does the recolonisation fauna reflect the new environmental conditions? (e.g., diversity and sensitivity indices).
- To what extent does the recolonisation fauna differ from the background fauna?
- Can general impacts of trawling/dredging be evaluated based on the results obtained in the inner Oslofjord?
Research methodologies and database:
The study will be based on the analyses of short sediment cores (0-4cm) along a transect across a local dredging area in the inner Oslofjord. The project will concentrate on the analyses of living benthic foraminifera, organic carbon and nitrogen, and metal concentrations.
Learning outcomes:
The student will be involved in field and laboratory work. They will be expected to produce their own data and to describe and summarise the results in a scientific manner. The student will contribute to establishing the applicability of benthic foraminifera as a biomonitoring tool reflecting the ecological status of an environment.
