Composition and Distribution of Macrobenthic Invertebrate Fauna 



89 



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NEMERTEA 



Figure 57 

 Geographic distribution of Nemertea: A — number of specimens per square meter of 

 bottom; B — biomass in grams per square meter of bottom. 



The relation of nemertine biomass to temperature 

 range differed from that of density, exhibiting a gen- 

 eral increase in biomass (from 0.22 to 1.38 g/rrr) as the 

 temperature range broadened (Tables 23. 24; Fig. 61). 

 Largest average biomass occurred where the range was 

 16° to 19.9°C, and smallest where it was less than 4°C. 



The frequency of occurrence of nemertines in rela- 

 tion to temperature range was similar to their density 



distribution. The highest percentage (52 to 49%) of 

 samples containing specimens occurred in areas with 

 intermediate temperature ranges. Where the tempera- 

 ture range was narrow or broad, the frequency of oc- 

 currence was relatively low (Table 25). 



Relation to Sediment Organic Carbon 



The average density of nemertines exhibited a rather 



