Scholarlink

<p>Archean ocean marine primary productivity may have been limited by biologically available nitrogen. Due to low molybdenum abundances, early biological nitrogen fixation is thought to have relied on alternative nitrogenases that incorporate vanadium or iron instead of molybdenum. Here, we examine nitrogen fixation in a Cyanobacteria-dominated, ferruginous, low-sulfate, low-molybdenum lake, which replicates biological and chemical conditions relevant to early marine primary productivity. Nitrogen fixation occurs even when molybdenum is &lt;1 nM, 100x less than the abundance in modern oceans. Molybdenum additions did not increase nitrogen fixation rates, indicating that diazotrophs were not molybdenum limited. Only the molybdenum-iron nitrogenase was detected in metagenomes and metatranscriptomes, indicating that the alternative nitrogenases were not required. We suggest that low sulfate (&lt;1 μM) and/or efficient uptake mitigated molybdenum limitation. These results indicate that molybdenum bioavailability may be strongly controlled by sulfate and that alternative nitrogenases are not essential for nitrogen fixation at low molybdenum.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Lowering the Mo limit for nitrogen fixation by Mo-nitrogenase

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年1月14日

查看全文
  • Zackry Stevenson,
  • Dylan L. Schultz,
  • Michelle Chamberlain,
  • Kathryn Rico,
  • Ariel Anbar,
  • Anne E. Dekas,
  • Elizabeth D. Swanner

摘要

Archean ocean marine primary productivity may have been limited by biologically available nitrogen. Due to low molybdenum abundances, early biological nitrogen fixation is thought to have relied on alternative nitrogenases that incorporate vanadium or iron instead of molybdenum. Here, we examine nitrogen fixation in a Cyanobacteria-dominated, ferruginous, low-sulfate, low-molybdenum lake, which replicates biological and chemical conditions relevant to early marine primary productivity. Nitrogen fixation occurs even when molybdenum is <1 nM, 100x less than the abundance in modern oceans. Molybdenum additions did not increase nitrogen fixation rates, indicating that diazotrophs were not molybdenum limited. Only the molybdenum-iron nitrogenase was detected in metagenomes and metatranscriptomes, indicating that the alternative nitrogenases were not required. We suggest that low sulfate (<1 μM) and/or efficient uptake mitigated molybdenum limitation. These results indicate that molybdenum bioavailability may be strongly controlled by sulfate and that alternative nitrogenases are not essential for nitrogen fixation at low molybdenum.