Change in the water quality in Lake Ohnuma, Hokkaido, Japan: a comparison of 1977 and 1996

DOI PDF Web Site Web Site 被引用文献5件

この論文をさがす

説明

Annual variations in nutrients, algal biomass, and primary production were investigated in Lake Ohnuma, Japan, in 1996 in order to compare them with 1977. Chloro- phyll a concentrations gradually increased after the ice melted and reached a maximal value of 20.7 I gl 21 in August. Phosphate concentrations in the lake were close to the de- tection limit throughout the study period, whereas sufficient nitrate remained even in the productive summer season. In contrast, in the summer of 1977, both nutrients were ex- hausted, and primary production was less than 0.2 g C m 22 day 21 . Primary production in 1996 ranged from 0.4 to 5.8 g C m 22 day 21 , which was 2 to 30 times higher than 20 years ago. These results indicate that the lake has become eutrophic in the last two decades. A comparison of the nutrients in the inflowing river between 1977 and 1996 indicated that nitrate and ammonium concentrations were markedly elevated in the rivers, and therefore the nitrogen loading to the lake tripled.

収録刊行物

  • Limnology

    Limnology 1 (1), 63-68, 2000-04-28

    Springer Science and Business Media LLC

被引用文献 (5)*注記

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ