294 POPULATIONS OF THE SEA 



C'^ method (1952, 1958a), which have given such valuable results, 

 have again raised many problems related to the actual behavior 

 of the species which are responsible for the observed production. 



These examples may suffice to indicate the variety of unsolved 

 problems that are suitable for experimental studies. In spite of 

 the shortcomings in methods which still adhere to the field ecologi- 

 cal surveys of marine phytoplankton, it seems obvious, as far as 

 this branch of marine biology is concerned, that Dr. Redfield's 

 warning against too one-sided an experimental approach does not 

 apply at all. The experimental studies have by no means kept 

 pace with the observations of populations in the sea. On the other 

 hand, the little work which has been done on phytoplankton cul- 

 tures has demonstrated how essential a background of field ob- 

 servations is for a sound evaluation of experimental results. One 

 need refer only to the temperature experiments, which illustrated 

 so clearly the necessity of checking results obtained in the labora- 

 tory with the actual distribution pattern of the species in the sea. 

 On the whole, the experience gained from experimental studies 

 supports the generally adopted view that research on en\'iron- 

 mental influence should be organized in such a way as to establish 

 a close collaboration between workers with a first-hand knowledge 

 of field surveys and skilled experimentators. 



With regard to the special branch discussed here, the time seems 

 ripe for an extension of research in the laboratory. The new tech- 

 niques developed recently should be employed and developed fur- 

 ther to exploit more effectively the wealth of observations ac- 

 cumulated through field ecological studies. In view of the fact that 

 the marine vegetation is responsible for at least as large an annual 

 production of organic matter as that of all the terrestrial plants, 

 there seems to be no reason why such an expansion should be made 

 at the expense of work of the survey type. The present eftorts in 

 this field seem to be quite out of proportion to the role which these 

 marine plants play in the organic cycle as a w^hole. 



REFERENCES 



Allen, E. J. 1914. On the culture of the plankton diatom Thalassiosira 

 gravida Cleve in artificial sea-water. /. Marine Biol. Assoc. United 

 Kingdom, 10, 417-439. 



