51 



We have been looking at a number of different species in Florida. 

 We screened about 50 local indigenous species to look for the one 

 that looked best, that grew fastest and was easiest to grow, and 

 ended up with one called Gracilaria. It is a red seaweed. 



It also has the advantage that it contains the commercial poly- 

 saccharide agar, which gives it commercial value. The advantage of 

 Gracilaria is that it will grow in Florida all year round. It stays in 

 a vegetative condition. It never becomes reproductive. This is a big 

 advantage. It just proliferates itself and breaks up into little pieces 

 that you can continually crop it off and maintain it at its optimum 

 density all the time, and this is an ideal situation for getting 

 maximum productivity. 



We were able to get a yield, in a small scale experimental 

 system, of the equivalent of 52 tons per acre per year, which is 

 very high. Taking the organic fraction, this would be half of that, 

 26 tons per acre per year. That is about as high as any documented 

 yield for any plant on Earth. 



The only things that are comparable to it are water hyacinths, 

 which are extremely productive, and that was also the result of 

 some of our experimental work in Florida. The best yields of sugar- 

 cane in the tropics, around 20, and there are a couple of tropical 

 grasses that are comparable to this. 



The last page of my testimony shows some of these high yields. 

 You have to be a little careful of these data because, again, these 

 are the total dry weight yields. I have not tried to show ash free 

 organic matter because this is not given for a lot of the terrestial 

 crops, so I didn't want to guess that. 



But you can see from this that the aquatic plants, the Gracilaria, 

 the kelp and so on, are up as high as most of the terrestial plants, 

 either on a small experimental scale or on a large commercial scale 

 as well. 



This same Gracilaria that we are growing in Florida is grown 

 commercially in Taiwan in large ponds about 25 acres in size and 3 

 feet deep that were designed originally for growing fish. The people 

 have found that they can make more money by growing Gracilaria. 



They get yields that are much lower than we get in Florida, a 

 tenth as high. Instead of 25 ash free tons per acre they get about 

 2 ¥2. They do it in a very simple manner. They just let the seaweed 

 sit on the bottom of the pond and grow by itself and when it is 

 grown up a bit they harvest some of it out and spread the rest of it 

 around and let it continue to grow. 



Our rule of thumb as a result of this and some of our own work 

 is that the more energy you put into the system the higher the 

 yield you get, and somewhere there is an optimum with respect to 

 the energy balance. This is what we are now going to be trying to 

 find out, where in this system do you get the best energy output 

 relative to energy input. This is something we have got to find in 

 the next year or so. 



But, equally important I think, is, having found the potential for 

 these plants we have got to begin developing technology for grow- 

 ing them out in the open ocean. I think it is unrealistic to think 

 that one could grow these on a large scale in our coastal areas, or 

 on land along the coast. This is some of the most valuable land 



