AUTHOR=Seyler Lauren M. , Tuorto Steve , McGuinness Lora R. , Gong Donglai , Kerkhof Lee J. 

TITLE=Bacterial and Archaeal Specific-Predation in the North Atlantic Basin

JOURNAL=Frontiers in Marine Science

VOLUME=6

YEAR=2019

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2019.00555

DOI=10.3389/fmars.2019.00555

ISSN=2296-7745

ABSTRACT=<p>Stable isotope probing (SIP) was used to track prokaryotic and eukaryotic carbon uptake along a meridional transect (Long. 52°W) in the North Atlantic to assess if <sup>13</sup>C-resource partitioning between bacteria and archaea and <sup>13</sup>C-labeled eukaryotic predators could be detected. One-liter SIP microcosms were amended with <sup>13</sup>C-acetate or <sup>13</sup>C-urea and incubated for 48 h. Our data indicated archaea often outcompeted bacteria for <sup>13</sup>C-urea while both archaea and bacteria could incorporate <sup>13</sup>C-acetate. This <sup>13</sup>C label could also be tracked into eukaryotic microbes. The largest number of <sup>13</sup>C-labeled eukaryotic OTUs, and the greatest percentage of eukaryotic <sup>13</sup>C signal, were observed in conjunction with both archaeal and bacterial <sup>13</sup>C incorporation, suggesting that most eukaryotic predators do not distinguish between archaeal and bacterial prey. However, other <sup>13</sup>C-eukaryotic OTUs were exclusively associated with either <sup>13</sup>C-archaeal or <sup>13</sup>C-bacterial OTUs. These archaeal-specific and bacterial-specific <sup>13</sup>C-eukaryotic OTUs were related to known bactivorous predators including <italic>Ancyromonas</italic>, <italic>Amastigomonas</italic>, <italic>Cafeteria</italic>, and <italic>Caecitellus</italic>. Our SIP findings suggest both resource partitioning between bacteria and TACK (Thaumarchaeota, Aigarchaeota, Crenarchaeota, and Korarchaeota) archaea and selective predation by eukaryotic predators. Determining the equalizing mechanisms for co-existence in the marine environment can help map predator/prey interactions to better estimate carbon flow in the deep ocean.</p>