No abstract

The potential errors in the various tcchniqucs for the Winkler m&hod have been cxamincd and a new tcchniquc dcvclopcd.The accuracy of this technique has been tested by comparison with standards based on dissolving known quantities of oxygen in oxygen-free water. An accuracy of 0.1% was obscrvcc~, so the tcchniquc nppcars suitable for oxygen analysts requiring an accuracy of grcatcr than the 3-50/o obscrvcd with tho common techniques.INl'nODUC'l'ION

An extended series of measurements of oxygen solubility in pure water and dilutions of seawater over the temperature range 0.5 to 35C was made. Nonlinear dependence of oxygen solubility on chlorinity was found. Interpolation tables of the data have been prepared. The accuracy of the techniques was approximately 0.1%, so the tables appear to be more reliable than those in current use. Because many of the existing field data have been collected using techniques for the Winkler method that introduce significant systematic errors due to volatilization and air oxidation errors, the use of the reported solubility values with these field data will produce misleading results.

Chlorinated waters are being introduced into estuarine and coastal areas in increasing quantities. In such systems, the chlorine reacts with the natural bromide and ammonia to produce the highly toxic hypobromous acid, hypobromite ion, and haloamines. Sunlight causes up to 50 percent conversion to bromate ion, which is persistent in natural waters and has an unknown toxicity.

The bioluminescent, photosynthetic, tropical marinc dinoflagellate Pyrodinium bahamense occurs in persistent high concentrations in Oyster Bay, Jamaica, W. I., although mean tidal flushing rates determined by dye-tracer techniques would predict their disappearance.As a result of a unique temporal sequence of positive phototaxis and the differential movement of diurnal wind-driven water layers of different densities, there is a daily transfer of P. bahumense into the eastern shallows of the bay where flushing rates are minimal, reducing the effect of the mean bay dilution.A second phototaxis-dependent mechanism in the eastern shallow results in zones of high concentration containing up to 10,000,000 P. buhamense per liter. This latter mechanism can explain the production of red water outbreaks in coastal waters. Nitrogen and phosphorus levels observed are consistent with both mechanisms.

A new tracer technique for the direct observation of movement and dispersion of estuarine and inshore waters is described. The method utilizes the fluorescent organic pigment, rhodam.ine B, together with a very stable, compact filter fluorometer. The tracer is very satisfactory with regard to stability, cost, toxicity, and detectability. Its nearly unique fluorescent and absorption spectra minimize the effect of natural background so that concentrations as low as 2 x 10-11 have been observed in the field, with expectations that this detection limit can be lowered to 4 x 10-1 2. Advection and diffusion from approximate point sources discharged in Baltimore Harbor, in Conowingo Lake, and in Chesapeake Bay were measured. Theoretical models of hOIizontal diffusion are compared to the observed decrease in concentration with time. 1. TRACER TECHNIQUE

Bioluminescence and phytoplankton successions during 1969 indicate large oscillations from the stable Pyrodinium bahumense populations normally associated with bioluminescent bays. A mathematical model is proposed which relates meteo,rological conditions to positively and negatively phototactic dinoflagellate populations. The model and additional circumstantial evidence indicate that Bahia bioluminescent bay.

Magnesium was estimated using a weight photometric titration procedure after chromatographic isolation of the magnesium. Chlorinity was estimated using weight titration with a fluorometric end point. Samples collected in the Sargasso Sea were analyzed, and temporal or depth variations of the magnesium-chlorinity ratios were within the analytical uncertainties of 0.05%. The mean value of the ratio was found to be 0.06626, which is discrepant from previous estimates by 1%. The spectacular 'temporal variations of alkaline earth element to chlorinity ratios in theSargasso Sea' reported by Billings et al. [1969, p. 231] are in sharp contrast to expectations based on the knowledge of the oceanography of the area. In particular, the observations of magnesium to chlorinity (Mg/C1) ratios varied by as much as 10%, which would require substantial processes of additions and removals of magnesium and halides. As these authors point out, explanation of the results requires identification of either a new mechanism of oceanic mixing and transport phenomena or unsuspected errors in atomic absorption analyses.In an effort to verify these observations of temporal variations, a program of further sampling was undertaken by this group. As a part of this program it was desirable to have samples analyzed using other analytical techniques. We were invited to participate, and this paper described the results of our analyses of samples collected on four occasions during November 1967 through January 1968 at a station located at approximately 32ø10'N, 64ø30•W (23 km SE of the Bermuda Islands). Additional samples were collected but were not analyzed because of the monotony of the results.An additional purpose of our work was to determine the Mg/C1 ratios with a greater precision and accuracy than had been undertaken • Now at Rosenstiel