THE ECOLOGY AND BEHAVIORAL PATTERNS OF THE MOTILE FAUNA 

 ASSOCIATED WITH TROPICAL MARINE SOFT BOTTOM COMMUNITIES 



Renate Schlenz True 

 Bio-Oceanic Research, Inc. 



ABSTRACT 



The study of the behavior of the small motile fauna present among 

 the leaves of Syringodium filiforme , a marine sea-grass, showed 

 that crustaceans are the predominant group of organisms present at 

 daytime, while molluscs are the ones more abundant at night. 



Daily variations of dissolved oxygen ranged from 5.2 to 7.2 ppm 

 and the temperature from 28.2 to 28.8°C (July 1970). 



A patch of plastic artificial sea-grass of 1.5m x 1.5m showed that 

 juvenile fish found protection from the opened environment among 

 the plastic blades. After a week's time one species of foraminifera 

 and one species of a red calcareous algae were present on the 

 plastic leaves in the same percentage as they were found on the 

 natural sea-grass. After two weeks a small branched green algae 

 had attained the size of 1 cm. 



OBJECTIVE 



The purpose of this study was to find out the daily variations on the number 

 of individuals as well as the zoological composition of the small motile fauna 

 accompanied by the variations of dissolved oxygen present among the leaves of 

 marine sea-grasses. 



A patch of artificial sea-grass was introduced in the environment for additional 

 information on the behavior of the small motile fauna by having the major daily 

 dissolved oxygen variation ruled out, as well as the additional food source 

 (from the sessile organisms growing on the leaves). Also, a study on the rapid- 

 ity of organisms' settlement over the artificial sea-grass was to be followed 

 to compare to the already existing sessile fauna and flora present on the natural 

 leaves. 



EQUIPMENT 



30cc plastic syringes 



Plastic bags 



Note boards 



Nets with 1mm x 1mm mesh (size of squares) mounted on a metal frame of 30cm in 



diameter 

 A patch of artificial sea-grass made of plastic green ribbons 5mm wide and 50 



to 70 cm long, mounted on a base of chicken wire 1.50m x 1.50m 

 Thermometer 

 Dissecting scope 

 Weston and Stack dissolved oxygen analyzer 



VI-209 



