atmosphere that is probably proportional 

 to productivity, which means that the 

 highly productive coastal zones are 

 probably regions of relatively high 

 input of sulfur to the atmosphere. 

 Another high input of sulfur to the at- 

 mosphere is from the burning of fossil 

 fuels which contain sulfur. We associ- 

 ate acid rain with the burning of fossil 

 fuel, which is probably correct, but at 

 the present time there is a certain 

 amount of controversy as to the relative 

 magnitude of sulfur production by the 

 volatilization of sulfur from natural 

 and anthropogenic sources. This is of 

 practical importance because of the role 

 of sulfur in acid rain. 



There are two ways in which we look 

 upon elements like nitrogen and phospho- 

 rus as key elements in aquatic coastal 

 systems. One is as limiting factors, 

 and the other is as causes of eutrophi- 

 cation. Let us look first at the limit- 

 ing factor aspect. In 1925, W. R. G. 

 Atkins (1925) noted that the ratio of 

 nitrogen to phosphorus in the English 

 Channel was 16 atoms of nitrogen to 1 

 atom of phosphorus. This was true of 

 both the material in solution in the 

 water and the material bound in plank- 

 ton. He noticed that in summer the 

 nitrogen and phosphorus were depleted 

 from the water and were tied up in the 

 plankton at exactly the same time. Red- 

 field (1934) extended the observation to 

 the North Atlantic, and showed that the 

 ratio of 16 to 1, nitrogen to phospho- 

 rus, was true for surface ocean water in 

 general in the North Atlantic. 



This has become known as Redfi eld's 

 ratio because he extended it and pro- 

 posed its cause. By recycling these ele- 

 ments so rapidly, the phytoplankton come 

 to control the ratio in the whole sys- 

 tem. Redfield's ratio has come to be a 

 kind of magic thing for ecologists, and 

 we look for it wherever we go. We seldom 

 find it except in the open ocean. In 

 the coastal waters, one may find ratios 

 as low as 3 to 1, or 1 to 1, much less 

 nitrogen in proportion to phosphorus. 

 This has led many people to say that 

 nitrogen is the limiting element in the 

 coastal zone, which may be true. 



However, the absolute amount of 

 nitrogen in the coastal zone is far 

 greater than in ocean surface water, so 

 the limitation of production, if any, is 



a relative one. In the ocean there is 

 relatively little nitrogen fixation or 

 denitrification. In the coastal zone 

 both processes are active, and the N:P 

 ratio is controlled by the relative 

 rates of those two processes. 



Our other concern is eutrophica- 

 tion. The salt marsh in Georgia is a 

 eutrophic system. It is a natural eutro- 

 phic system, about as eutrophic as it 

 could be without going out of balance. 

 So eutrophication is not necessarily 

 something that man does to systems. We 

 can find systems which are naturally 

 very productive and which an ecologist 

 would call eutrophic systems. On the 

 other hand, there are systems which are 

 not naturally eutrophic which man can 

 influence by organic pollution from 

 human sewage waste or from industrial 

 organic waste. When we make them eutro- 

 phic, this usually leads to a condition 

 which is not aesthetically pleasing to 

 us. Eutrophication may have other 

 problems associated with it. It cer- 

 tainly will change the system. 



We can point to certain examples of 

 this; New York Harbor and Houston Ship 

 Channel are in competition for the worst 

 system in the country, if not in the 

 world (Smith 1972). Both are complicat- 

 ed cases because there are various types 

 of pollutants present, not just organic 

 matter and nutrients, but toxins and 

 organic compounds of all kinds. Eutro- 

 phication is certainly part of the 

 problem in both systems, and probably 

 both are less eutrophic than they would 

 be if they were not toxic. 



The old saying of the engineer is 

 that the solution to pollution is dilu- 

 tion. We have been applying this to the 

 rivers and lakes of our continent and we 

 have nearly reached the end of that. We 

 have been applying it to the estuaries 

 and we have nearly reached the end of 

 that, too. Now we are looking at the 

 ocean as the ultimate sink for our ex- 

 cess waste. Right now, this is the 

 cheapest thing to do. I suppose in the 

 long run we could find ways to use 

 wastes more effectively, to economically 

 recycle them effectively rather than 

 throw them away. In the long run the 

 best thing to do is not throw away ni- 

 trogen and phosphorus, and then find 

 new sources for agriculture. In the 

 short run, we have to throw them away 



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