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Home About Us  Habitat Mapping Pontoon Estuary Offshore
Results Discussion and Conclusion

Introduction:

From the data we hoped to determine estuary classification as defined by water mixing and flow. Also of interest: riverine and terrigenous inputs of major nutrients, how they behave in the estuary and the effect of plankton on nutrient levels and freshwater nutrient input to the ocean.


Methodology:

















CTD Deployment

Set the Niskin bottles ready to fire and switch on the CTD. Begin to deploy the CTD when the dry-lab team are ready and the winch operator is ready, stabilising the CTD by hand. Stop lowering the CTD when it reaches the surface and inform the dry-lab team. Relay the information from the dry-lab team to the winch operator, taking Niskin bottle samples at depths of interest. Retrieve the CTD and relay the Niskin bottle water to the wet-lab team. Switch off the CTD.

THE FAL ESTUARY SURVEY:

Plankton Net

Deploy the 200 micron mesh zooplankton net with 4-5m of cable and collect samples for 5 minutes. Bring the net back on deck and rinse with the hose to ensure all the sample ends up in the sampling bottle. Transfer the contents into another bottle for analysis at a later date.


Secchi Disk

Deploy the Secchi disk and continue to lower it until it is no longer visible. Retrieve the Secchi disk back on deck and measure the length of cable, taking into account the height of the boat (90cm) and the length of cable between the disk and first mark on the cable (52cm).

Hover  over image for  description:

Abstract:
The aim of the Fal estuary survey was to ascertain its chemical, biological and physical properties during the transition from fresh river water to water of increased salinity. As the salinity of the estuary increased the concentration of silicate, nitrate and phosphate all decrease, suggesting removal behaviour. Populations of zooplankton are greatest the further from the mouth of the estuary conversely populations of phytoplankton are lowest in this area due to consumption by zooplankton.

Station Locations - Click to enlarge