MEASURING THE PRODUCTIVITY OF THE SEA 



6l 



In the section across the Pacific 

 from New Zealand to Cali- 

 fornia a highly productive 

 region was found a little to the 

 north of the Equator. Grams 

 of carbon per square metre of 

 surface per day. 



••0,101 



[ •0,13 L 

 0^4^mi i i. 



^ \. \ ■ ■■ 



i^New Zealand 



0.097 to o-^9 grams of carbon assimilated by plankton algae per 24 hours 

 per square metre of surface. In the coastal regions and the equatorial 

 area referred to the production was about 0.5 grams. There was really 

 no poor area. A striking difference was found between this section and 

 the one extending from Panama to Denmark. Production in the Sar- 

 gasso Sea was only 0.05 grams. Even so, this is 10 per cent, of the pro- 

 duction in the rich areas of the Pacific, and 2 per cent, of that in the 

 richest region off the south-west coast of Africa. There are no "deserts" 

 in the oceans. 



What is the annual production of all the oceans? It is true that the 

 Galatheas studies covered large areas and showed that variation is 

 comparatively small. Even so, the data available is by no means adequate 

 for a final answer. No attempt has been made to measure the production 

 of large sea areas such as the Antarctic Ocean. Nevertheless, an ap- 

 proximate answer can be given. Our calculation is 15,000 million tons 

 of carbon, corresponding to about 40,000 million tons of organic matter, 

 a year. This is roughly the same as the estimated annual production of 

 organic matter on land. 



Many people will be surprised to hear that the sea can rival the land 

 in production, but there is not the slightest doubt that the most productive 

 areas of the sea can produce as much as our best cornfields. Two further 

 points which should be borne in mind are that large areas of the earth 



