N₂ fixation is a major component of the global N cycle and has been extensively studied in open-ocean and terrestrial ecosystems. Yet rates and ecological dynamics remain virtually unknown for the inland and coastal aquatic ecosystems (lakes, wetlands, rivers, streams, and estuaries) that connect terrestrial and marine biomes. This is due to the diversity of these habitats as well as the traditional paradigm that N₂ fixation rates were low to nonexistent, and therefore not important, in these ecosystems. We identify three major research themes to advance understanding of aquatic N₂ fixation: (1) the biological diversity of diazotrophs and variability of N₂ fixation rates, (2) the ecological stoichiometry of N₂ fixation, and (3) the upscaling of N₂ fixation rates from genes to ecosystems. Coordinating research across these areas will advance limnology and oceanography by fully integrating N₂ fixation into ecological dynamics of aquatic ecosystems from local to global scales.

中文翻译：

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固氮：沿淡水-海洋连续体的一个鲜为人知的过程

N ₂固定是全球氮循环的主要组成部分，已在公海和陆地生态系统中得到广泛研究。然而，连接陆地和海洋生物群落的内陆和沿海水生生态系统（湖泊、湿地、河流、溪流和河口）的速率和生态动态仍然几乎未知。这是由于这些生境的多样性以及在这些生态系统中 N ₂固定率低或不存在因此不重要的传统范式。我们确定了三个主要研究主题，以促进对水生 N ₂固定的理解：(1) 固氮菌的生物多样性和 N _{2固定率的可变性，(2) N 2}的生态化学计量固定，和（3）从基因到生态系统的 N _{2固定率的升级。}跨这些领域的协调研究将通过将 N ₂固定完全整合到从地方到全球尺度的水生生态系统的生态动态中来推进湖泊学和海洋学。