Falmouth Group 8

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All nutrients measured and salinity increase from 15m to 41.6m. Salinity increases from 15 to 41.6. Silicon increases from 0.87 umol/L to 3.00 umol/L. Phosphate increases from 0.073umol/L to 0.280umol/L. Nitrate increases from 0.04 to 0.64 umol/L.

Amounts of nutrients increasing from samples at 15m to 41.6m shows the difference in amounts of nutrients above and below the 1% light depth. All nutrients are increasing due the falling of aggregates from surface waters to deep waters.  

Time: 12:23 (UTC)

Lat: 50 10.724 N

Long: 004 48.483 W

Wind: 350° 13.7 knots

Cloud: 8/8

Nutrients

The graph shows less chlorophyll at 40m than at 15m. Dissolved oxygen is also lower at 40m and supersaturated at 15m. For this station the secchi depth was 7m, implying a 1% light level at 21m, therefore the sample at 40m is likely below the compensation depth, accounting for the dissolved oxygen depletion. Because only two data points were taken it appears that the chlorophyll decreases linearly, but this is not the case according to the fluorometer data. There is a step decrease between the two samples at around 20m.

Secchi: 7m

Chlorophyll and  Dissolved Oxygen

The profiles for all the variables measured are relatively more stable and show little change with depth, although the depth range sampled here is much smaller. Fluorescence only displays a slight linear reduction with depth, whilst temperature remains at a similar value throughout. Irradiance levels and salinity display a very similar trend as to all the previous station readings.

The thermocline now occurs further from the surface, which has allowed substantial numbers of phytoplankton to reside even near the surface. This is likely accounted for by the greater amount of mixing occurring here, which drives the thermocline deeper and allows nutrients to replenish the surface waters.

CTD

Backscatter: An area of High back scatter (higher return) from 0-20m corresponding to high chlorophyll readings from the CTD is the most likely phytoplankton. Some faint layers are visible from 20-30m which could be from turbulence caused by shear stress between layers.

Velocity and direction: 0-20m shows a clear SE flow, and 20-30m shows a thin SW flow with speeds  <0.1m s-1. At depths of 30-60m is flowing East.

ADCP

Station 4

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