AUTHOR=Caputo Andrea , Stenegren Marcus , Pernice Massimo C. , Foster Rachel A. 

TITLE=A Short Comparison of Two Marine Planktonic Diazotrophic Symbioses Highlights an Un-quantified Disparity

JOURNAL=Frontiers in Marine Science

VOLUME=5

YEAR=2018

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2018.00002

DOI=10.3389/fmars.2018.00002

ISSN=2296-7745

ABSTRACT=<p>Some N<sub>2</sub>-fixing cyanobacteria form symbiosis with diverse protists. In the plankton two groups of diazotrophic symbioses are described: (1) a collective group of diatoms which associate with heterocystous cyanobacteria (Diatom Diazotroph Associations, DDA), and (2) the microalgal prymnesiophyte <italic>Braarudosphaera bigelowii</italic> and its relatives which associate with the unicellular cyanobacterium <italic>Candidatus</italic> Atelocyanobacterium thalassa (hereafter as UCYN-A). Both symbiotic systems co-occur, and in both partnerships the symbionts function as a nitrogen (N) source. In this perspective, we provide a brief comparison between the DDAs and the prymnesiophyte-UCYN-A symbioses highlighting similarities and differences in both systems, and present a bias in the attention and current methodology that has led to an under-detection and under-estimation of the DDAs.</p>