SUPERSATURATION OF ATMOSPHERIC GASES IN THE COASTAL 

 WATERS OF THE GULF OF MAINE 



By Alden p. Stickney, Fishery Biologist 



Blreal' of Commercial Fisheries Biological Laboratory 



West Boothbay Harbor, Maine 04575 



ABSTRACT 



Year round observations of dissolved oxygen in 1964-67 

 regularly revealed supersaturation of 120 to 150 percent 

 during the spring and summer. Seasonal variations took 

 the form of a sinusoidal cycle that showed definite phase 

 relations to temperature. Comparisons with data for 

 offshore dissolved oxygen showed that in general the 

 coastal waters were more highly supersaturated. 



Nitrogen measurements made in conjunction with 

 those of oxygen led to the conclusion that oxygen super- 

 saturation was usually due to photosynthesis, but oc- 

 casionally supersaturation of both gases indicated some 

 physical cause. 



Supersaturation of oxygen in marine waters, 

 particularly in coastal areas, is not uncommon, and 

 references to it are numerous in the literature. Its 

 effect on marine life has apparently not been in- 

 vestigated, nor are there adequate records for com- 

 parison with observed fluctuations in distribution 

 or abundance of organisms. 



The coastal waters of the Gulf of Maine support 

 several tislieries, chief among which are those for 

 lub.sters (IIo?ncn-iis aniencanus M. Edw.) and for 

 Atlantic herring {CJupea harencpix harengus L.). 

 The herring fisherj' in particular suffers from ir- 

 regular periods of poor catches due to unfavorable 

 distribution (hence, lack of availability) as well 

 as to low abundance. The causes for these irregu- 

 larities in availability are not known. 



To seek possible relations between herring dis- 

 tribution and hydrography, the Bureau of 

 Commercial Fisheries Biological Laboratory in 

 Boothbay Harlxir, Maine, is investigating several 

 aspects of the hydrography of coastal watei-s. In- 

 terest in dissolved oxygen stemmed primarily from 

 an outlireak of gas disease in the laboratory aquaria 

 in June l!l6-t. At that time the sea water in these 

 aquaria effervesced with tiny bubbles; several 

 herring died from gas disease and many more 

 showed the typical symptoms — disorientation, 

 exophthalmia (popeye), and bubbles in the fins 

 and lateral line organs. This disease is frequently a 

 result of supersaturation caused by defects in the 



Published August 1968. 



FISHERY BULLETIN: VOL. 67, NO. 1 



water pumping system. Cai'eful inspection of our 

 system, however, revealed no defects. Furthermore, 

 Winkler tests of water taken directly from the 

 harbor as well as that supplied through the pump- 

 ing system showed substantial supersaturation of 

 oxygen. Whether the supersaturation was due to 

 excessive dissolved air, or to oxygen only, was not 

 determined at the time as no equipment was then 

 available at the laboratory for measuring nitrogen. 

 Routine measurements of dissolved oxygen began 

 in the early sunnner of 1904:, but nitrogen measure- 

 ments were not undertaken until IOCS. 



Although some data on dissolved oxygen have 

 been published for the Gulf of Maine (Gran and 

 Braarud, 1935; Rakestraw, 1933; Colton, Marak, 

 Nickerson, and Stoddard, 1968), these recoixls are 

 limited to short periods during a few years and 

 cover mainly the open waters of the Gulf rather 

 than the inshore regions. Only occasional measure- 

 ments have heretofore been made in the coastal 

 waters. 



METHODS 



^^"ater samples for oxygen analysis were not 

 taken according to a regular schedule, but were 

 spaced to provide a fair coverage of each month. 

 Samples were taken three to five times per week 

 in spring and summer and about once a w'eek in 

 fall and winter. The most conveniently and fre- 

 quently sampled source was the water pumped into 

 the laboratory from a depth which varied accord- 



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