_J 



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z 

 >- 



X 



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o 



CO 



w 



32 

 30 

 28 



12- 



9- 



3h 







p 

 o 



0( 



^6 6 



8 8 



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8 



o 



.8 e 



o 



eo 



6 



8 



o 

 o 

 o 



o 



o: 



I- 

 < 

 q: 



UJ 



a 



z 



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20- 

 15- 

 10 



5 







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e 



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8 5 

 o 



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1970 



1971 



972 



1973 



Figure 20-2. Narrangansett Bay bottom water salinity, dissolved 

 oxygen and temperature (monthly measurements at sampling 

 site, Vz mile north and southwest of site). 



NOTE: Each circle represents a single measurement made on a single day (3 

 replicate measurements). 



Burrowing activities were described and quantified by observing single 

 worms in sediment-filled thin aquaria (2 cm thick, 14 cm wide and 15 cm 

 deep). These aquaria were maintained in flow-througli systems at appropriate 

 temperatures. The thin aquaria allowed free three-dimensional movement 

 (worms can easily turn in 1 cm thick aquaria), yet also permitted direct 

 observation of some activities with a stereomicroscope when the worms 

 burrowed along the glass. The glass walls are considered to represent an 

 obstacle to the worm not unlike buried rocks or bivalve shells, which are 



306 



