18 NATURE AND RELATIONS OF BIO-ECOLOGY 



Shelf ord and Towler (1925). In their study of communities in the 

 San Juan Channel of Puget Sound, Shelford and Towler found the 

 general principles drawn from plant communities by Clements to be 

 readily applicable. The analysis yielded three benthic formations or 

 climaxes with two associations each and a number of more or less 

 definite serai stages. This investigation w^as carried forward by 

 several other studies, such as one into the relations of the different 

 barnacle dominants by Towner (1930), the value of these as indicators 

 of salinity (Rice, 1930), and the connection between salinity and the 

 size and form of dominants (Worley, 1930). In 1935, Shelford, Weese, 

 Rice, McLean, and Rasmussen brought together the results of their 

 work covering succession to land, describing a fourth bottom forma- 

 tion and mapping the communities of the area. They found only a 

 little evidence of succession in the partially enclosed waters, though 

 Hewatt (1935) described it for the open coast. 



Eddy (1925-1927); Gersbacher (1937). For a number of years, 

 Eddy (1925-1927) carried on investigations of fresh-water plankton 

 from the standpoint of development and traced the origin of a pelagic 

 community in Lake Decatur, formed by impounding water to pro- 

 duce an urban supply. In six years such a community has developed 

 through the addition of species from year to year, but without the 

 disappearance of any of these, thus affording a basis for dealing with 

 the problem of pelagic climaxes. Gersbacher (1937) presented a de- 

 tailed account of the development of bottom communities in new lakes 

 including fishes (see also Shelford and Eddy, 1929, a). 



Molander; Gislen (1930). In separate though related investiga- 

 tions of Gullmar Fjord in Sweden, Molander and Gislen have applied 

 the methods of Petersen, employing the bottom sampler to determine 

 numbers and weights. Molander has considered the bottom commu- 

 nities of animals primarily on clay, since the samples from hard- 

 packed sand, coarse gravel, or pebbles are not dependable. He recog- 

 nizes nine associations, several of them with two or three variants or 

 facies, which are regarded as exhibiting a close analogy with many of 

 those of Petersen. 



Gislen proposes three new terms for biotic communities, viz., epi- 

 biose, endobiose, and hypobiose, the first two corresponding to Peter- 

 sen's onfauna and infavma. He employs facies in a different meaning, 

 epibioses showing soft and hard bottom facies, and endobioses oligo- 

 tropic facies on sand or rock bottoms, eutrophic ones on clay or on 

 substrata with more or less organic material. A system of life forms 

 is outlined, and extensive tables are given of the production in terms 

 of grams per quadrat. Somewhat more than twoscore associations are 

 recognized in accordance with the usage of plant sociologists; many 

 of these are faciations, consociations, or societies in the classification 

 employed by dynamic ecologists. 



Bio-ecology and Oceanography. It is evident that oceanography is 

 ecology in so far as it measures the physical factors of marine habitats 

 and the reactions of organisms upon them. In its recent development, 

 the growing feeling for quantities and communities stamps it as marine 

 ecology in every significant respect, though, as with all fields of special 



