SESTON COMPOSITION AND DISTRIBUTION IN THE BOTTOM WATER OF 



GREAT LAMESHUR BAY 



Wolfgang Hickel 



Biologische Anstalt Helgoland 



Hamburg, West Germany 



ABSTRACT 



During October 19. to 26., 1970, investigations of seston quantity 

 and quality were carried out at three locations near the TEKTITE 

 habitat. A table (p. 3) shows the data of organic carbon of seston 

 and phytoplankton as well as of nitrogen in the seston. The 

 distribution and composition of seston in the bottom water was 

 fairly homogeneous. 



OBJECTIVE 



The aim of these investigations was to analyze the quantity and quality of the 

 seston in the near bottom water layer of the Great Lameshur Bay. The possible 

 influence of the kind of bottom substrate and of the vertical distance from 

 the bottom was to be considered. The qualitative composition of phytoplankton, 

 the phytoplankton biomass, the weight, organic carbon and nitrogen content of 

 the seston were investigated. 



PROCEDURES 



During TEKTITE Mission No. 15, water samples were taken near the habitat 

 usually twice a day in the period from October 19. to 26., 1970. The sampling 

 of 5 to 10 liters was done using plastic bags. Three locations were selected 

 for repeated sampling: 



1. Coral reef west of the habitat: 30 m southwest of habitat entrance 

 at 0.5 m above the bottom in a depression between the coral growth. 

 Water depth 14 m. 



2, Over the sandflat which extends west of this reef. 50 m west-north- 

 west of habitat entrance, 25 m apart from the edge of the reef. 



2. a. 0.5 m above the sand bottom. Water depth 18 m. 



2.b. 5 m above the bottom. 13 m of water depth. 



Following subsamples were taken: 



1. 100 ml of water were preserved with Lugol's iodine solution. 



Phytoplankton cells were counted using the sedimentation technique 

 with an inverted microscope. 



VI-275 



