Seasonal dynamics of carbon stable isotope ratios of particulate organic matter and benthic diatoms in strongly acidic Lake Katanuma

Hideyuki Doi, Eisuke Kikuchi, Shuji Hino, Takeru Itoh, Shigeto Takagi, Shuichi Shikano

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

Lake Katanuma is a strongly acidic volcanic lake (average pH 2.2) located in NE Japan in which only 2 algal species are found: Pinnularia acidojaponica, a benthic diatom, and Chlamydomonas acidophila, a phytoplankton species. Although the δ13C of phytoplankton generally varies seasonally in lake ecosystems, in Lake Katanuma the mean δ13C of particulate organic matter (POM, mainly phytoplankton) is constrained to a narrow range from -26.4 to -23.7‰. A major reason for this is the continuous supply of dissolved CO2 gas available to C. acidophila from fumaroles at the lake bottom. The δ13C of P. acidojaponica in Lake Katanuma varied seasonally and was positively correlated with P. acidojaponica abundance at 1 and 4 m depths. This suggests that the higher P. acidojaponica biomass at 1 and 4 m produced the 13C-enrichment in the high-density algal mats because of the limited dissolved CO2 gas. The mean δ13C of benthic diatoms was higher than that of phytoplankton in Lake Katanuma, although the diatoms seemed to assimilate the same carbon source (CO2 gas) in the lake water.

Original languageEnglish
Pages (from-to)87-94
Number of pages8
JournalAquatic Microbial Ecology
Volume33
Issue number1
DOIs
Publication statusPublished - 2003 Aug 21

Keywords

  • Acidic conditions
  • Benthic diatoms
  • Carbon stable isotope
  • Inorganic carbon
  • POM
  • Phytoplankton
  • Seasonal variation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

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