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

海洋的生产力受到营养物质可用性的限制，这对大气和海洋之间的碳通量有影响。在之前的奖项中，PI 发现以前未被识别的固氮单细胞蓝藻在寡营养海洋中活跃且丰富。这一发现对于海洋中的氮循环以及“新”氮在碳固定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在空间和时间上似乎是分离的。其次，地理分布和控制分布的因素尚不清楚，因此尚不清楚如何将这些生物体纳入生物地球化学模型。最后，其中一组蓝藻似乎能在白天固定 N2，这重新揭示了同时进行固氮和光合作用的谜团，而这个谜题之前仅限于对 Trichodesmium 的讨论。

The productivity of the oceans is limited by the availability of nutrients, which hasimplications for the fluxes of carbon between the atmosphere and oceans. In a previousaward the PIs found that previously unrecognized N2-fixing unicellular cyanobacteriaare active and abundant in oligotrophic oceans. This finding has important implicationsfor 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 ofcyanobacteria that appear to be separated in space and time, due to unknownecological variables. Second, the geographic distribution and factors controlling thedistribution are unknown, so it is not clear how these organisms should be included inbiogeochemical models. Finally, one of the groups of cyanobacteria appears to fix N2during the day, which revives the enigma of simultaneous nitrogen fixation andphotosynthesis that was previously limited to discussions of Trichodesmium.