OCEANOC^APHIC INVESTIGATIONS 



359 



and will in general be smaller. Also, considering the fact that needed accuracy is only about 

 ±1/2 ft, it is evident that the system described herein provides sufficient accuracy for most 

 purposes. Once the float has been installed it can be left in place, except that when not being 

 used it should be secured about 15 to 20 ft below the surface. 



INVESTIGATION OF THE EFFECTS OF THE SEALAB H ENVIRONMENT ON PLANTS 



To determine the effects of the Sealab environment on the germination, growth, and de- 

 velopment of plants, an attempt was made to grow barley (avivat), marigolds (Spungold) and 

 Alaskan peas during the submergence of Sealab II. This experiment was designed and directed 

 by the Department of Plant Sciences, Texas A & M University; the writers potted and maintained 

 the plants aboard Sealab, along with a log of their germination, growth, and development. The 

 plant experiment consisted of two 12 -in. -square wooden trays, each containing 25 small pots 

 filled with peatmoss, perlite and slow-release fertilizers (Fig. 135). The pots were planted 

 with seed and placed in Sealab prior to germination. Each box initially contained 15 pots of 

 barley and 10 pots of marigolds, while each pot was planted with two seeds. The Alaskan peas 

 were not planted until the second week of Team 2's occupancy of Sealab, at which time ten pots 

 of marigolds were removed and replaced with the peas. A bank of eight 50-w Sylvania rough 

 service incandescent frosted bulbs located some 66 cm (26 in.) from the surface of the boxes 

 provided light. A plexiglas filter 0.33 in. thick was positioned in front of the light source to 

 protect the plants from excessive heat. The plants were watered as required and checked two 

 to three times per week to record germination and growth. During the first week a heavy mold 

 developed and completely covered the surface of the pots. Even though a fungicide was admin- 

 istered two to three times per week, this mold persisted throughout the plant experiment and 

 was, no doubt, an important factor in this experiment. 



Fig. 135. Sealab II plant experiment 



Of the plants tested, barley was the only plant that was able to withstand successfully the 

 severe environment offered by Sealab. Germination was successful in 29 of the 30 pots planted 

 with this seed, and both seeds germinated in 27 of these pots. Only one marigold and two 

 Alaskan peas germinated; these died shortly after germination, reaching a height of only a few 

 centimeters. When Sealab was brought to the surface, the barley, which grew to a maximum 

 height of approximately 18.5 cm (7.5 in.), was cut off at the soil level, dried, and sent to Texas 

 A & M for chemical analysis. A control experiment is planned by Texas A & M in which similar 

 seeds will be germinated and grown under normal pressure and Sealab atmosphere, and under 

 normal pressure and atmosphere. The results of these experiments, along with a complete 

 report of the Sealab plant experiment will be the subject of a report by Texas A & M University. 



