Ref ID : 1197
Kawabata Zen'ichiro and Kurihara Yasushi; Effects of the consumer on the biomass and spacial heterogeneity in the aquatic microcosms. Sci.Rep.Tohoku Univ.Ser.IV (Biol.) 37:219-233, 1978
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Spacial heterogeneity is one of the common characteristics of both the biotic and abiotic components of ecological systems. It was attempt to show the effects of the consumer on the spacial heterogeneity and biomass from the descriptions of the behaviors of four kinds of microcosms containing or devoid of Aeolosoma hemprich, a kind of aquatic oligochaetes, of each medium with or without polypeptone as an organic matter. All of these microcosms were derived from the microcosm which was characterized by the formation of colonies. The system devoid of A. hemprich did not lead to the colony formation. So, the comparison was made of the behaviors of the systems containing A. hemprich with that devoid of it in order to understand the role which A. hemprich plays in the formation of micro-spacial heterogeneity and the colonies, and in the changes in biomass of each population throughout the successions. Furthermore, it was analyzed how these two systems behave when they were introduced into the circumstances of extremely scarce nutrients from the viewpoint of effects of A. hemprich on the biomass and the spacial heterogeneity. The results obtained were as follows: 1) From the observations of serial changes of each organism for the systems with or without either A. hemprich and/or the 0.01% polypeptone, the presence of A. hemprich was necessary for the formation of colonies. 2) Vertical stratification was observed for each organism. The formation of the stratification was not depend on the presence of A. hemprich in the system with polypeptone. On the other hand, the presence of A. hemprich contributed to some extent to the stratification in the system with extremely scarce nutrients. 3) Most of the organisms, namely Chlorella, were observed in aggregates. This was pronounced in the system with A. hemprich and extremely scarce nutrients. The total and mean areas, and the numbers of floc were increased in the system with A. hemprich and with extremely scarce nutrients. A. hemprich contributed to form the spacial heterogeneity. This heterogenity had a tendency to be formed easily in the system with extremely scarce nutrients. 4) Generally, the biomass of each organism and the total biomass were greater in the system with A. hemprich than in the system without A. hemprich. This tendency was pronounced in the system with extremely scarce nutrients.