Table 7. Concentrations of total and biologically available 

 protein at Jordan Basin. 



Depth Total Available % 



(m) Protein 1 Protein 1 Available 



2 above 0.53 0.11 21 



bottom 



5 from 2.76 2.31 84 



surface 



1 u mole Pr-N/L 



DISCUSSION 



In summary, three particle maxima were observed at Jordan 

 Basin and two at Mt. Desert Island. The surface layer at Jordan 

 Basin had higher chlorophyll concentrations, autotrophic 

 nanoplankton numbers, and particle volumes than the Mt. Desert 

 Island station, but other analyses indicated no significant 

 differences. An intermediate particle maximum was observed at 

 Jordan Basin which was enhanced in protein, but not other 

 constituents. The BNL, which was characterized by a sharp 

 gradient in light transmission and particle volume, did not show 

 gradients in most of the biological or chemical constituents, 

 except some protozoans. Considerable temporal/spatial 

 variability was apparent in the BNL for replicates obtained 

 within a short time, which may obscure gradients. The BNL at the 

 Jordan Basin station was less biologically enhanced than the Mt. 

 Desert Island station and the organic material appeared to be 

 more degraded. Nevertheless, the BNL at Jordan Basin was more 

 biologically enhanced over the clear water above than at the Mt. 

 Desert Island station, probably because the clear water at Jordan 

 Basin was much clearer than at Mt. Desert Island (Fig. 2) . 

 Finally, there were differences at all depths, but especially in 

 the BNL, between the two sampling dates at Jordan Basin. The 

 data cannot be used to distinguish between two alternate 

 explanations: a fall bloom occurred in response to a storm and 

 the material was transported vertically or horizontal advection 

 patchiness changed the characteristics of the water and 

 particles at the one location. In conclusion, there was some 

 evidence that the BNL at some stations in the Gulf of Maine was 

 biologically enhanced, and could, thus, serve as a food source 

 for benthic organisms and demersal fishes. 



While it seems to be generally agreed that BNL are 

 biologically enhanced (e.g., Karl et al., 1976; Rowe and Gardner, 

 1979; Wishner, 1980 a, b, ; Angel and Baker, 1982; Smith, 1982; 

 Kawana and Tanimoto, 1984; Wishner and Meise-Munns, 1984; Gowing 



199 



