Microscale distribution of oxygen and a possible role of biota in its generation

Open (don't having a membrane) oxygen sensor was used for towing in the tro pical Atlantics. The depth of the rowing was regularly changed at interval 0.2-1.6 m due to pitching. Fast response time of the sensor gave opportunit y to measure microscale distribution on the scale tenth meters - 1 m (low f requency) and on the scale 100-1 cm (high frequency). Simultaneously with t he distribution of oxygen the speed of sound in water was measured under sp atial distribution 1 m. It was used as features of variation of temperature and salinity that could have direct or indirect effect on oxygen concentra tion. Measured variability of sound speed did not correlated with low frequ ency variability of oxygen and thus the latter was due to spatial (basicall y vertical) inhomogenity of oxygen production by phytoplankton. The high fr equency variability was basically due to turbulent disintegrating of low fr equency variability but at exceptional case it was due to inhomogenity of p hitoplankton distribution on the scale several centimeters.