Diurnal Studies

 This section presents the results of two twenty-four hour

 studies of the fluctuations of temperature, salinity, pH, and

 dissolved oxygen at six sites in Benner Bay and the Lagoon.

 Measurements and water samples were taken at each station at

 three hour intervals. Data were also taken periodically on

 sunlight intensity, air temperature, wind, sea and tide state.

 Diurnal fluctuations of water quality parameters in

Banner Bay and the Lagoon are the result of physical and bio-

logical dynamics which are extremely variable from site to

site. Tidal effects on salinity, temperature, etc. vary de-

pending on the site, because of the peculiar combination of

wave and tidal forces throughout the area and fluctuations

of these parameters follow an unusual spatial sequence dic-

tated by the local bathymetry and shoreline irregularities.

 Besides the familiar pumping effect of tidal action on

water movement, the state of the tide is also critical to

water movement induced by wind and waves offshore of the

Lagoon. The offshore currents south of the cays have a

westerly set with velocities, varying with the tide, from

2.4 to 28.8 ft./min. (McNulty, 1960; Michel, 1970).

McNulty's group found that at slack tides the drift was in-

terupted and either no current was measured or there was a

weak easterly current.


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