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Production ecology of phyto‐ and zooplankton in a eutrophic pond dominated by Chaoborus flavicans (Diptera: Chaobolidae)
Author(s) -
Iwakuma Toshio,
Shibata Kin'ya,
Hanazato Takayuki
Publication year - 1989
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/bf02346942
Subject(s) - zooplankton , dry weight , phytoplankton , eutrophication , zoology , biomass (ecology) , biology , chlorophyll a , daphnia , plankton , ecology , phosphorus , botany , nutrient , chemistry , organic chemistry
Primary production of phytoplankton and secondary production of a daphnid and a chaoborid were studied in a small eutrophic pond. The gross primary production of phytoplankton was 290 gC m −2 per 9 months during April–December. Regression analysis showed that the gross primary production was related to the incident solar radiation and the chlorophyll a concentration and not to either total phosphorus or total inorganic nitrogen concentration. The mean chlorophyll a concentration (14.2 mg m −3 ), however, was about half the expected value upon phosphorus loading of this pond. The mean zooplankton biomass was 1.60 g dry weight m −2 , of which Daphnia rosea and cyclopoid copepods amounted to 0.69 g dry weight m −2 and 0.61 g dry weight m −2 , respectively. The production of D. rosea was high during May–July and October and the level for the whole 9 months was 22.6 g dry weight m −2 . Chaoborus flavicans produced 10 complete and one incomplete cohorts per year. Two consecutive cohorts overlapped during the growing season. The maximum density, the mean biomass, and the production were 19,100 m −2 , 0.81 g dry weight m −2 , and 11.7 g dry weight m −2 yr −1 , respectively. As no fish was present in this pond, the emerging biomass amounted to 69% of larval production. The production of C. flavicans larvae was high in comparison with zooplankton production during August–September, when the larvae possibly fed not only on zooplankton but also algae.