PROCEDURES 



Water Sampllns for Dissolved Oxygen Analysis 



Water samples were taken using plastic syringes which were completely filled 

 with water and then closed with caps to prevent any loss. These syringes were 

 also differently labeled to avoid confusion among the samples and enclosed in 

 a plastic bag for transportation. Once back in the habitat, the dissolved oxy- 

 gen was immediately measured by introducing the probe of the apparatus directly 

 into the now carefully opened syringe, through the large end. 



The Weston and Stack dissolved oxygen analyzer was calibrated against values 

 obtained through the chemical analysis of the water by the Winkler method. The 

 water used for the calibration had been previously saturated in oxygen by let- 

 ting air bubble in sea water for a period of two hours. Before additional 

 measurements of dissolved oxygen were taken, the apparatus was recalibrated 

 against known values of samples using sea water saturated in oxygen. The appa- 

 ratus gave the readings directly in ppm. 



The Collecting and Analysis of the Motile Fauna 



Using a net, 40 fast strokes were done among the vegetation (artifical and 

 natural) always in the same way to collect the small motile fauna. The net was 

 then enclosed in a plastic bag to avoid losses of organisms during transporta- 

 tion. Once back in the habitat, the organisms were separated from the debris, 

 then identified as well as possible with the available bibliography and their 

 numbers counted. The organisms were then released back into the marine environ- 

 ment. 



Additional Manipulations 



Samples of sea-grass leaves (artificial and natural) were also taken. A record 

 of temperatures was also kept. 



Sampling Plan 



The sampling was planned for different times every day so as to cover a 24-hour 

 pattern of the behavior of the motile fauna and dissolved oxygen in the water 

 in the period of two weeks. 



RESULTS 



The area studied was at about 360m north of the TEKTITE II habitat location in 

 15m depth. It is an extensive sea-grass bed of the species Syringodium f ili - 

 forme. The leaves are up to 40 cm long, with an average of 30 cm, and their 

 rhizomes and roots are up to 5 cm deep in the coralligenous sand and are less 

 developed than the leaves system. This fact shows that the plant itself, for 

 its survival, depends more on the photosynthetic activity than upon absorption 

 of substances from the sediment (which is a clean sand--poor in chemicals--as 

 opposed to mud). The marine sea-grass follows a vegetative starlike growth 

 pattern on the sediment and is mixed with different species of algae that occa- 

 sionally form patches, like the green algae: Penicillus pyriformis , P.capitatus , 

 Udotea flabellum , U.conglutinata , Halimeda incrassata , and Avrainvillea nigricans . 



VI-210 



