Oil-Eating Microbes Threaten Shipwrecks and Ocean Life
Bow of the Ewing Bank Wreck, a 19th-century wooden-hulled sailing ship that lies more than 2,000 feet (600 meters) below water. The image shows a close-up view of the copper sheathing attached to the outside of the wooden hull. After the vessel sank, it became a vibrant artificial reef now colonized by Lophelia pertusa coral (white), Venus flytrap anemones, and many other species of macrofauna. Credit: BOEM/Deep Sea Systems International
The microbes that once thrived around deep-sea shipwrecks in the Gulf of Mexico have transformed significantly after the Deepwater Horizon oil spill in 2010, according to a new study. These dramatic changes to the microorganisms that live on and near historically significant vessels could wreak havoc on the vessels and ocean life itself, researchers say.
There are more than 2,000 known shipwrecks on the ocean floor in the Gulf of Mexico, spanning more than 500 years of history, from the time of Spanish explorers to the Civil War and through World War II, according to the researchers.
“The first time I saw a chart showing the abundance of shipwrecks along our coasts, my jaw dropped,” said Jennifer Salerno, a marine microbial ecologist at George Mason University in Virginia. “You can’t look at an image like that and not question whether or not they are impacting the environment in some way.” [Shipwrecks Gallery: Secrets of the Deep]
These decades-to-centuries-old wrecks can serve as artificial reefs supporting deep-sea ecosystems, “oases of life in an otherwise barren deep sea,” Salerno told Live Science. “Once you put something, anything, in the ocean, microorganisms will immediately colonize it, forming biofilms. These biofilms contain chemicals produced by the microorganisms that serve as cues for other organisms like bivalves and corals to settle down and make a living on the wreck. In turn, larger and more mobile animals like fish are attracted to the presence of the smaller organisms — that is, food — and the three-dimensional structure of the ship itself, a good place to seek refuge from predators.”
The shipwrecks might also hold untold historical secrets. “The history of our species is not only encoded in our DNA; it is found in the physical remains left behind by past human populations. Archaeological sites such as historic shipwrecks — vessels that sank more than 50 years ago — represent snapshots of time from our collective human history,” said Melanie Damour, a marine archaeologist at the Bureau of Ocean Energy Management, an agency within the U.S. Interior Department. “Each and every shipwreck is unique and has its own story to tell — from how, when, and where it was constructed and by whom, to how it participated in the activities that shaped who we are today.”
In 2010, the Gulf of Mexico experienced the worst man-made environmental disaster in U.S. history, after explosions at the Deepwater Horizon oil rig caused more than 170 million gallons (643 million liters) of oil to spill into the water. In 2014, scientists launched a project to investigate the impacts of this catastrophe on deep-sea shipwrecks and the ecosystems they support in the Gulf — an estimated 30 percent of the oil from the spill ended up deposited in the deep sea, in areas that contain shipwrecks, the researchers said.
“What we hope to learn from this study is if those impacts will affect the long-term preservation of these sites, which, in turn, has significant repercussions for their continued ecological role and the amount of time that we have left to record their archaeological information before it is lost forever,” Damour, co-leader of the research project, told Live Science.
The scientists found that shipwrecks influence which microbes are present on the seafloor. These microbes in turn form the foundation for other life, such as coral, crabs and fish.