Home Offshore Time Series Geophysical Estuary

University of Southampton Falmouth Field Course 2013    26th June - 6th July 2013    Group 9

4th July 2013 – Estuary Sampling

Falmouth Tides (UTC): HW 02:09 4.20m

LW 09:31 1.50m

HW 15:39 4.30m

LW 22.03 1.5m

Introduction

An estuary is a partly enclosed body of water with tide, wave and fluvial processes combining to create unique physical, chemical and biological structures (Monbet 1992, Evans et al. 2003). The structure of the estuary is influenced by fresh and saltwater input along with external factors such as wind speed. The flushing time is the time taken to replace the freshwater volume of the estuary at the rate of net flow. The physical structure of the estuary determines the mixing taking place and therefore manipulates the chemical and biological components.

Samples were taken against the flood tide, to prevent sampling the same body of water. Eight stations were sampled at different locations in the Fal Estuary. Whilst sampling factors were considered;  flushing time of the estuary, physical structure and the nutrient environment.

The flushing time is the time taken to replace the freshwater volume of the estuary at the rate of net flow (Choi et al. 2004). The physical structure of the estuary determines the mixing taking place. The collection of data relating to physical parameters will allow the structure of the Fal estuary to be determined. The nutrient environment will be investigated through the collection of seawater samples and subsequent laboratory analysis.   

References

Choi K. W., Lee J.H.W. (2004). Numerical determination of flushing time for stratified water bodies. Journal of Marine Systems. 50 (3-4), 263-281.

Evans, G., Prego, R. (2003). Rias, estuaries and incised valleys: is a ria an estuary?. Marine Geology. 196 (3-4), 171-175.

Monbet, Y. (1992). Control of phytoplankton biomass in estuaries: a comparative analysis of microtidal and macrotidal estuaries. Estuaries, 15(4), 563-571.

Estuary