Before you do a dive in the Alvin submersible you hear all sort of stories about how you are down all day without a bathroom and how cold it gets. My first question to the pilot was, if you pass out how do I get this thing back to the surface? Once I had this down I was ready to go. As the hatch closed and we were lifted into the Gulf of California waters over the Guaymas Basin all this was running through my head. My first thought was, “I’m in this sub for the next 8-10 hours and I can’t get out.”. All those concerns quickly faded away once we started to dive and I began seeing the bioluminescent organisms being stirred up around us as we dove to 2000m. Why was I doing this? Obviously because I was invited to! Also, I have been studying the microbiology of this fascinating hydrothermal environment for the last eight years, and this was my first time seeing with my own eyes. Prior to this I had only studying environments, which I could sample myself, so getting a chance to dive at Guaymas was a no-brainer. More importantly, years of studying the sediments around these deep-sea vents have revealed a vastness of new microbial diversity and loads of insights to metabolisms of uncultured lineages. In short, this hard to reach habitat has become central to my research.
Andreas Teske (UNC Chapel Hill) and myself on the RV Atlantis just before we boarded the Alvin submersible (behind us) in November 2018.
With each round of metagenomic sequencing we obtain from Guaymas results in a variety of new phyla. For example, last year published a paper describing dozens distinct branches of life (Dombrowski et al 2017 and 2018). In fact with each new round of sequencing we obtain we continue to recover new phylum-level diversity. Which has us wondering will we ever at see all the phyla, classes, or orders in these sediments? Among these newly described phyla are several new members of the Asgard archaea (Zaremba-Niedzwiedzka et al. 2017). One of these is Helarchaeota (named after the Norse goddess of the death who lives in the underworld), which is described in this paper by my student Kiley Seitz (Seitz et al. 2019). These first genomes of Helarchaeota were recovered at and around a vent site referred to as “site 14”. This was one of our stops during my first visit to Guaymas. As you can see in this image of that particular location these sediments are very dynamic. There are large shifts in community structure vents. This is readily apparent to the naked eye from with variations in the mats that are thriving on the surface. If you consider how we have only done high-throughput sequencing of around 15 cores from Guaymas and how much we have expanded the tree, it become clear that we have only scratched the surface of this environment.
Top view of “site 14” hydrothermal seep and white, orange, and yellow colored microbial mats growing on the surface of the Guaymas Basin seafloor.
I went down thinking this is something I need to once in my life, and came back thinking, I need to do this again. I feel like I didn’t see enough. The eight hours we spent down there flew by as if we were there for just a few hours. Once you start seeing the hot fluids and how there the microbial mats and streamers are growing around it, you have a much more clearer sense of Guaymas is a wonderland of microbial communities. I am certain future studies of Guaymas communities will reshape the tree of life and continue to give us expected physiological surprises. You may be wondering do other Norse gods dwell here? I can tell you, yes they do.
The Alvin being recovered after a dive to the Guaymas Basin.
Dombrowski N, Teske AP, Baker BJ. (2018) Extensive metabolic versatility and redundancy in microbial diverse, dynamic Guaymas Basin hydrothermal sediments. Nature Comm.9, 4999.
Seitz KW, Dombrowski N, Eme L, Spang A, Lombard J, Seiber J, Teske AP, Ettema TJG, Baker BJ (2019) New Asgard archaea capable of anaerobic hydrocarbon cycling. Nature Comm.In press.
Dombrowski N, Seitz KW, Teske AP, Baker BJ (2017) New insights into microbial hydrocarbon cycling and metabolic interdependencies in hydrothermal sediments. Microbiome. 5:106.
Zaremba-Niedzwiedzka, K, Caceres EF, Saw JH, Bäckström D, Juzokaite L, Vancaester E, Seitz KW, Anantharaman K, Stott MB, Nunoura T, Banfield JF, Schramm A, Baker BJ, Spang A, and Ettema TJG. (2017) Asgard archaea illuminates the origin of eukaryotic cellular complexity. Nature 541, 353-358.