Diurnal oxygen changes at Station 7 (Figure 11) are

similar to those at Station 9 and indicate maintenance of

nocturnal oxygen concentrations by transport associated

with the tides. Oxygen concentrations were least dynamic

that is, showed the least degree of change, at Station 9

(Figure 12). Changes in concentration follow gentle slopes

and the dissolved oxygen is, except for a few hours during

the day, near or below saturation. The maximum concentra-

tion attained during the day was the lowest for all stations

studied. On the other hand, nighttime minima were not as

low as at Station 10, probably because of the greater volume

of water and apparently lower benthic biomass at Station 9

(the bottom here is patchy Thalassia, as opposed to a dense

cover at Station 10). Oxygen curves at Station 9 are very

similar to the salinity curves which may indicate that oxy-

gen changes here are due mainly to transport. This interpre-

tation is supported by the fact that nighttime concentrations,

on both occasions, did not fall steadily, but were supported

during the flood and high tide (2000-2400 hours). In fact,

there is bulge or "knee" in both curves during this period.

 The greatest diurnal oxygen consumption is indicated at

Station 10 (Figure 13) where dissolved oxygen is far below

saturation for all but six hours during the day.. In addi-

tion, there is a considerable lag in oxygen buildup in the


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