Collaborative: Biology and Ecology of Newly Discovered Diazotrophs in the Open Ocean

海洋的生产力受到营养物供应的限制，这对大气和海洋之间的碳通量产生影响。 在之前的一项研究中，PI发现以前未被识别的N2固定单细胞蓝藻在贫营养海洋中活跃且丰富。这一发现对海洋中的氮循环和“新”氮在固碳中的作用具有重要意义。 PI将解决三个主要问题：首先，由于未知的生态变量，至少有两个不同的蓝藻群体在空间和时间上似乎是分开的。其次，地理分布和控制分布的因素是未知的，因此不清楚这些生物应如何纳入地球化学模型。最后，其中一组蓝细菌似乎在白天固定N2，这恢复了以前仅限于讨论束丝藻的同时固氮和光合作用的谜团。

The productivity of the oceans is limited by the availability of nutrients, which has implications for the fluxes of carbon between the atmosphere and oceans. In a previous award the PIs found that previously unrecognized N2-fixing unicellular cyanobacteria are active and abundant in oligotrophic oceans. This finding has important implications for nitrogen cycling in the oceans and for the role of "new" nitrogen in carbon fixation. The PIs will address three major issues: First, there are at least two distinct groups of cyanobacteria that appear to be separated in space and time, due to unknown ecological variables. Second, the geographic distribution and factors controlling the distribution are unknown, so it is not clear how these organisms should be included in biogeochemical models. Finally, one of the groups of cyanobacteria appears to fix N2 during the day, which revives the enigma of simultaneous nitrogen fixation and photosynthesis that was previously limited to discussions of Trichodesmium.