PHySICAL OCEANOGRAPHY OF THE GULP OF MAINE 



683 



"Arctic ^current" chills the surface there would demand. This upper stratum was 

 as cold in Massachusetts Bay (farthest i-emoved from the effect of the Nova Sco- 

 tian current of spring) as it was off Penobscot Bay. 



In August, 1914, we again found the mean temperature of the inner part of 

 the basin of the gulf highest in the eastern side near Lurcher Shoal, lowest in 

 the western side off Cape Elizabeth, and slightly higher (7.7° to 9.9°) in the north- 

 eastern part in general than in the western (6.8° to 8°), as follows; 



Similarly, the mean temperature of the upper 80 meters (the whole column) was 

 as high on German Bank (9.9°), off Machias, Me. (9.7°), and at the western end of 

 the Grand Manan Channel (9.8°) in August, 1912, as it had been off Penobscot 

 Bay or on Platts Bank a week previous (9° to 9.7°), or as it was in Massachusetts 

 Bay two weeks later (about 9.6°). The 80-meter mean was slightly higher off Cape 

 Cod, however (about 11°), on August 29 of that year. 



Our data do not afford so satisfactory a regional survey of the mean temperature 

 of the coastwise zone shoaler than 50 to 60 meters because we have taken few obser- 

 vations so close to the land, and it is obvious that regional comparisons for any given 

 stratum within this belt will be misleading unless the observations are made at 

 approximately the same date and at localities where the depth of water is about 

 equal. The few readings that have been taken on Nantucket Shoals show the 

 whole colmnn of water 1° to 2° warmer (mean about 10° to 12°) than in equal depths 

 in the Bay of Fundy (mean 9° to 10°), an instructive comparison because the temper- 

 ature is kept nearly uniform, vertically, in both these areas by the swirling tides. 

 The mean was also slightly higher over the 50-meter contour in Massachusetts Bay 

 in August, 1922 (11.7° and 13°, stations 10633 and 10640), than we have found it 

 at about this depth off Mount Desert and farther east along the coast of Maine at the 

 same season (usually 9° to 10°) ; higher, too, than the mean at 35 meters depth in Passa- 

 maquoddy Bay in August (10° to 11°), ^^ though the difference in depth would sug- 

 gest a relationship of the opposite sort. 



Our summer cruise of 1913 afforded evidence to the same effect, the mean tem- 

 perature being considerably lower on German Bank (8.7°, station 10095) at the end of 

 the second week of that August than off Cape Elizabeth (about 11° at station 10103). 

 In August, 1914, also, the mean for the upper 50 meters was about 9.7° on German 

 Bank and between 10° and 11° near the Isles of Shoals across the gulf. However, 

 in the cold summer of 1916 (p. 628) the mean for 40 to 45 meters was almost exactly 

 the same at two stations in Passamaquoddy Bay in mid-August (8.5° and 9.4°), in 



™ Calculated from Craigie's (1916) temperatures. 



