期刊
FRESHWATER BIOLOGY
卷 57, 期 5, 页码 1042-1049出版社
WILEY-BLACKWELL
DOI: 10.1111/j.1365-2427.2012.02765.x
关键词
cyanobacteria; lake mixing; lake transparency; nitrogen fixation; photosynthesis
1. In situ measurements of nitrogen fixation rates for Aphanizomenon in fertile Colorado lakes with low inorganic nitrogen concentrations demonstrated high efficiency of nitrogen fixation at low irradiance. 2. For study populations, rates of N-2 fixation in darkness and with alternating exposure to light and darkness were a higher percentage of light-saturated rates for Aphanizomenon than for Anabaena, suggesting storage of reduced metabolites at high irradiance that are used subsequently by Aphanizomenon when cells are forced by mixing into zones of low irradiance. Also, saturation of N-2 fixation occurred over a lower range of irradiance for Aphanizomenon than for Anabaena. 3. High efficiency of N-2 fixation in Aphanizomenon at low or fluctuating irradiance is complementary to its previously demonstrated high efficiency of photosynthesis at low irradiance. Nitrogen fixation rate was also strongly related to DIN concentration; fixation was highest at low DIN (maximum < 5 mu g L-1) but was also most vulnerable to photoinhibition under such conditions. 4. The fixation capabilities of Aphanizomenon under weak or varying irradiance could explain its commonly observed domination over Anabaena when transparency is low and available nitrogen is scarce.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据