Dalton Hardisty: A View from the Ocean Floor
I peered through the porthole of the sub with my hands clasped around its edges to block any light from inside. As we descended from the ocean surface to its bottom nearly 1.5 miles below, I was awe struck by the pitch black that defines, and has for eons, the vast majority of the ocean—only occasionally lit by the bioluminescence streaming past. It felt like a dream. I was joined by a crew of two others, the pilot and another scientist, onboard the submersible Human Occupied Vehicle Alvin on the trip of a lifetime.
In Dec. of 2018, I had the opportunity to visit a location unique in our ocean today, but that represents an intersection of environments thought to have regulated ocean chemistry for much of Earth’s past and perhaps critical to the evolution of life itself. We were visiting hydrothermal vent fields—fissures where magma-heated water escapes from the seafloor—on the bottom of the Pacific Ocean.
You may remember the HOV Alvinfrom the movie The Titanic, where it is included in the opening scenes exploring the shipwreck for the first time. Owned by the Navy, but operated by Woods Hole Oceanographic Institution, the Alvinhas been part of key discoveries on the seafloor, ranging from the RSV Titanic, hydrothermal vents, to chemosynthetic organisms producing organic compounds from inorganic chemicals in the absence of sunlight. The three passengers sit crammed within a seven-foot diameter titanium sphere with mechanical arms and scientific instruments for sample and data collection, all in near-freezing waters and at pressures more than 200 times our atmosphere.
Was I nervous? Yeah! I was comforted though knowing that the Alvin crew has executed over 5000 dives without a life-threatening incident, having been briefed on the exhaustive list of safety protocols, and knowing that our pilot was well experienced. Perhaps more nerve-racking was knowing of the group of scientists staying on deck who were counting on me for their own success. Working together over the months preceding the expedition, a team of nearly 15 interdisciplinary scientists—including chemists, geologists, geophysicists, biologists, and microbiologists—worked with engineers and pilots to form an ambitious research agenda for the series of eight dives and multiple sites we would be visiting. This included placement of traps and harvesting of crabs and giant tube worms, or Riftia, emblematic to hydrothermal vent ecosystems, and—my own agenda—collecting super-heated water, sometimes nearly four times boiling, and the mineral-rich plumes emitting from the vents. Having the plan in place gave me the assurance necessary to execute the mission while having a blast, oohing and aahing like a kid at the new site around every corner.
My research in the Earth and Environmental Science Department at MSU focuses on constraining the chemical evolution of Earth’s oceans and atmospheres throughout its past. Molecular oxygen has been a key player in this story. Oxygen’s rise to the prominent 21% of our atmosphere and saturation of the ocean only culminated in the last few hundred million years, while beginning from scratch from the earliest photosynthetic organisms, cyanobacteria, as long as three billion years ago.
This reality is on prominent display outside of the Natural Science building on MSU’s campus, where a giant rock, a piece of banded iron formation from Michigan’s own Upper Peninsula, now sits. This rock, deposited on the seafloor over two billion years ago, is a testament to an ancient, oxygen-devoid ocean where chemicals—like iron—from hydrothermal vents were allowed to disperse throughout the ocean. The hydrothermal vents we visited in the submersible just last year play a lessened, yet still important role in regulating our ocean’s chemistry, and may provide clues to this fascinating past.
Seeing for yourself and hands-on experience are hard to replace. During our dive, I saw sites that I had read about, seen pictures of, worked with in the laboratory, and visualized over the years of my studies and research career, but that I now feel newly awakened to. We passed through oxygen-void waters absent of visible life, traversed over landscapes formed from recent seafloor volcanic eruptions, witnessed chimneys like castles spewing hydrothermal water and plumes of black “smoke”, and, amidst these ruthless environments, we saw oases of life—including tube worms as tall as a human—feeding in concert with bacteria from the vents and persisting nearly independent of the rest of the ocean life.
I am an Assistant Professor in MSU’s Department of Earth and Environmental Sciences. The opportunity to participate in this deep-sea project, lasting three weeks all together, was through an Early Career Scientist training expedition funded through the National Science Foundation. The expedition was aimed at giving young scientists the opportunity to plan and lead aspects of a shipboard and submersible-based field campaign on the ocean, thus forging a new generation to together take on the challenges and document the fascinating beauty and scientific lessons our ocean, mostly unexplored and changing in front of our eyes, has to offer.
No matter what your career or personal path may be, a life of intrigue and discovery is yours to take. That may have started at home, and I hope your tool box for this journey continues to grow here at MSU, but these are only your start. For me, I see journeys to the bottom of the ocean or the exciting follow up work with samples here in the laboratory on our campus, as beginning first steps leading to the questions—not culminations of my experience. Your training and learning never stops and you never know where curiosities stemming from your own backyard might take you.