Investigating the ecological impacts of salinity change in coastal lakes & wetlands using lake sediments

Past Life and Environments

QMUL

UCL

Broads Authority

Andrea Kelly

The stability and biodiversity of coastal lakes are seriously threatened by long-term changes in salinity resulting from sea-level rise or human activity in the catchment. Future management decisions depend on a sound understanding of the potential ecological impacts, but this is limited by short-term observations and measurements. Well dated, rapidly-accumulating lake sediments, conversely, span inter-annual to millennial changes, which can be validated and calibrated with historical records. The aims of the research are therefore to (1) use lake sediments to investigate causes and consequences of long-term ecological change in coastal wetland lakes and (2) to predict the impacts of future management schemes and sea level rise for aquatic ecology. The main emphasis is on the use of ostracod shell trace-element geochemistry to quantitatively reconstruct salinity by combining measurements of living ostracods with water chemistry. Plant and animal macrofossil remains will be used to assess ecological change with variations in salinity. Expanding upon a pilot study in the Thurne Broads system in Norfolk, this research will provide knowledge of seasonal variability, and enable the palaeosalinity of the whole system to be quantitatively reconstructed. Whilst site specific, the Thurne Broads will act as a ‘test-bed’ for assessing salinity changes in coastal wetlands elsewhere.

The research will investigate the causes and consequences of recent ecological change in lowland coastal lakes and contribute to improved methodology for palaeolimnological reconstruction in such environments.

It has the potential to inform conservation efforts to deal with future saline incursions due to sea-level rise.

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