Since the discovery of cable bacteria more than a decade ago, these sulfur-oxidizers have been found in sediments in a range of marine environments. However, we are still far from understanding the environmental relevance of cable bacteria in marine settings. In this study, we assess the abundance and activity of cable bacteria in biogeochemically well-characterized sediments from five hypoxic and anoxic basins along the continental margin of California and Mexico. Results of Fluorescence in-situ hybridization (FISH) reveal low numbers of cable bacteria in sediments of the hypoxic and anoxic San Clemente, Catalina, San Pedro and San Blas basins. In the anoxic Soledad Basin, in contrast, we find abundant cable bacteria near the sediment surface. Microprofiling of oxygen, sulfide, pH and electric potential reveal a lack of cable bacteria activity at the sites at the time of sampling. In our presentation, we will discuss the environmental factors that may contribute to the more abundant presence of cable bacteria in Soledad Basin when compared to the other basins. We also will specifically highlight the potential role of temporal variations in the supply of electron donors and acceptors near the sediment-water interface in creating a niche for cable bacteria in Soledad Basin.

Primary Presenter: Caroline Slomp, Utrecht University (c.p.slomp@uu.nl)

Authors:

Caroline Slomp, Radboud University  (caroline.slomp@ru.nl)

Martijn Hermans, Stockholm University  (martijn.hermans@su.se)

Sairah Malkin, Horn Point Laboratory, University of Maryland Center for Environmental Science   (smalkin@umces.edu)

Silke Severmann, Rutgers University  (silke@marine.rutgers.edu)

James McManus, Bigelow Laboratory for Ocean Sciences  ()

Niels van Helmond, Radboud University  (niels.vanhelmond@ru.nl)