Fullerton aims to identify purpose of underwater microbes

Microbes are everywhere. In the food we eat, on our skin and on every surface we touch.

Tiny living organisms that spend their entire lives at a size too small to be seen with the naked eye, microbes include bacteria, protists, types of fungi and even some species of animals. Although seemingly invisible, they affect our everyday lives in ways we most often times don’t notice: they boost our immune systems, purify waste water, make the fermentation of beer and wine possible, aid in the fight against infectious diseases and aid in the development of vaccines.

That’s what got Heather Fullerton, a post-doctoral fellow in the Department of Biology at Western Washington University, interested in the study of these tiny beings. A Washington native originally from Kirkland, Fullerton gained an interest in microbes while taking a biology class in high school and went on to major in microbiology at the University of Washington and obtain a doctorate in microbiology from Cornell University, where she became interested in microbial metabolism specifically.

Fullerton was hired by WWU Biology Professor Craig Moyer in the beginning of 2013 to do bioinformatics at Western. Her research is centered on sequencing the DNA of microbes known as Zetaproteobacteria. These lithoautotrophic microbes exist near hydrothermal vents, or “underwater volcanoes,” as Fullerton calls them, that emit a highly concentrated and reduced form of iron. Zetaproteobacteria exist on the chemical energy provided by the vents, oxidizing the iron that is being emitted to sustain life. Very little is known about these microbes, which were first discovered in 1995 at Lō’ihi Seamount by Moyer and his colleagues and were not officially described until 2007 as a completely new class of organism.

“My main goal, to put it simply, is to figure out who’s there and what they’re doing,” Fullerton said. “Every time we look into microbial systems, we find new microbial species that are similar to previously described organisms but are different enough to be classified as new. Most of the work I do is to describe these unique organisms at the genomic level, to determine what they are capable of doing and how that might impact the larger biosphere at hydrothermal vent habitats.”

Fullerton had the opportunity to travel to Hawai’i and visit Lō’ihi Seamount, a hydrothermal vent off the coast of the Big Island, in March 2013. Led by Moyer, who served as the chief scientist of the expedition, 19 microbiologists and biogeochemists spent a little over two weeks aboard the Research Vessel “Thomas G. Thompson,” with Fullerton and Moyer focused on studying Zetaproteobacteria and the microbial communities in which they exist.

The team of scientists worked in collaboration with trained pilots to use the remotely operated vehicle “Jason” to obtain samples of the microbial mat and view the seafloor and the different mat structures through the vehicle’s video and still imaging systems.

Moyer and Fullerton went on another research expedition to the Mariana Arc off the coast of Guam at the end of 2014 in collaboration with other universities and the National Oceanic and Atmospheric Administration (NOAA) to study Zetaproteobacteria found near the hydrothermal seamounts up and down the arc. The team was able to identify where the vents were by following trails of shrimp who were clustered near the hot water of the vents and appeared to be eating the microbial mat, which they obtained samples of with the same ROV “Jason” that they used in the 2013 trip to Lō’ihi.

With these samples, Fullerton has been working on taking the genomic data of the microbes from the different locations and doing comparisons between the two to find out how they relate and how they differ, a study known as biogeography.

Fullerton is in the process of applying for a grant from the National Science Foundation to go on another so-called “research cruise” to obtain more samples. The data they gather on these expeditions are only a snapshot of the activity that is going on around the submarine volcanoes. Going back to Lō’ihi or the Mariana Arc would allow them to have a better understanding of the microbes by seeing what has, or hasn’t, changed.

“Once I figure out what they’re capable of doing, then we can go back and ask, ‘What are they doing?’ We can get an idea of what to look for after identifying those key genes.” Fullerton explained. “We’re all trying to get back out there and sample it more and figure this stuff out. It’s a fundamental earth process that we don’t know much about.”

There is evidence that all of the metals that are coming out of the hydrothermal fluids help to spread metals throughout the world’s oceans, and some scientists have suggested that this mixture of heat from the hydrothermal vents with the cold seawater led to the formation of the first organic compounds.

“It’s a localized thing to study, but it has global implications,” said Fullerton.