Stanford researchers working with the U.S. Navy’s Marine Mammal Program in San Diego have discovered a startling variety of newly-recognized bacteria living inside the highly trained dolphins that the Navy uses to protect its ships and submarines, find submerged sea mines and detect underwater intruders. They found similar types of bacteria in wild dolphins as well.

“About three quarters of the bacterial species we found in the dolphins’ mouths are completely new to us,” said David Relman, Stanford professor of microbiology and medicine, and co-author of a paper published in the journal Nature Communications on Wednesday.

A U.S. Navy dolphin opens its mouth for a swab to collect bacterial samples.

“Bacteria are among the most well-studied microbes, so it was surprising to discover the degree to which the kinds of bacteria we found were types that have never been described,” he said. “What novelty means is not just new names of species, families, classes or phyla…there’s reason to believe that along with this taxonomic novelty, there’s functional novelty.”

The U.S. Navy has been training dolphins and sea lions to carry out defensive military missions from their bases in San Diego and elsewhere since the early 1960s.

Over the years, it has also funded scientific research and become the single largest contributor to the scientific literature on marine mammals, producing more than 800 publications, according to the Navy.

Relman started working with the Navy more than 15 years ago to identify bacteria suspected of causing stomach ulcers in their dolphins.

His latest project to catalog the bacterial communities (or microbiota) living inside the dolphins began when the Navy asked him to help develop a probiotic bacterial strain that could keep their dolphins healthy, or help sick dolphins get better.

Navy trainers took regular swabs from the dolphins’ mouths and rectal areas, using what looked like a Q-tip, and shipped the samples to Stanford on dry ice for analysis.

Stanford researchers analyzed oral, rectal and gastric samples from the U.S. Navy's dolphins and sea lions, as well as samples from the dolphins' blowholes and the surrounding water.

The study found a similar amount of diversity and novelty in bacterial samples taken from wild dolphins living in Sarasota Bay off the west coast of Florida, although there were slight differences in the bacteria from the dolphins’ mouths.

Relman said he hoped to develop a profile of the normal microbial communities in healthy dolphins and other marine mammals, so that scientists could detect any early change that might signify an imminent disease, or health problems caused by climate change and ocean warming.

“There’s a lot of concern about the changing conditions of the oceans and what the impact could be on the health of wild marine mammals,” Relman said. “We would love to be able to develop a diagnostic test that would tell us when marine mammals are beginning to suffer from the ill effects of a change in their environment.”

The research could help solve other mysteries, such as how dolphins digest their food, even though they swallow fish whole without chewing them.

The key could be a unique bacterial group that’s also been identified in an endangered species of freshwater dolphins living in China’s Yangtze River, said Elisabeth Bik, a research associate at the Stanford Department of Medicine and lead author on the paper.

“It’s a very intriguing bacterial group that nobody has seen before in any other terrestrial animal group,” said Bik. “I would really love to know more about those bacteria and sequence their genomes to understand more about their functional capacity.”

Zak, a 375-pound California sea lion, shows his teeth during a training swim. Zak has been trained to locate swimmers near piers, ships, and other objects in the water considered suspicious and a possible threat to military forces in the area.

“The sea lions and dolphins are kept at the same facility, they’re fed exactly the same fish, and they’re swimming in the same water…but they’re very, very different in terms of microbiota,” Bik said.

Unlike dolphins, sea lions share many common types of bacteria with their terrestrial cousins.

“Sea lions weren’t that different from other carnivores like dogs and cats,” Bik said. “They’re evolutionarily related to them, and their microbiota looks very similar to those animals. But dolphins don’t really have a terrestrial mammal that’s closely related, and their microbiota looks very different from anything else that people have seen.”

Relman said his team was planning on expanding their study to include other marine mammals such as sea otters, killer whales, baleen whales, grey whales, harbor seals, elephant seals and manatees. Their purpose, in part, is to understand how life in the sea, over the millions of years since the return of mammals, may have shaped the structure of their microbial communities and the roles they play in marine mammal health.

They’re already working to analyze more than 80 samples of killer whale stool that the U.S. National Oceanic and Atmospheric Administration has gathered with the help of specially trained sniffer dogs, which stand on the bow of their boats and point to fresh killer whale feces before it sinks.

The California Department of Fish and Wildlife is contributing samples from the sea otters and seals it studies as part of its conservation, ecological, and monitoring programs.

And the Marine Mammal Center in Sausalito, which is the West Coast’s largest rescue and rehabilitation facility for marine mammals, is sending samples from the seals in its care.

Relman said the research could help scientists begin to answer fundamental questions about life in the ocean.

“Marine mammals remain one of the more poorly understood habitats for studying microbial life, and there would be lots of reasons for thinking that these are important environments to study, in part because of the relevance for the health of these marine mammals, but also because they represent a view into what it means to live in the sea and the nature of our relationship with this vast aspect of our environment,” Relman said.

Collaborators and co-authors on this study included Stephanie Venn-Watson and Kevin Carlin from the National Marine Mammal Foundation, and Eric Jensen from the Space and Naval Warfare Systems Center Pacific, in San Diego.

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This book is a counter to the conventional wisdom that the United States can and should do more to reduce both the role of nuclear weapons in its security strategies and the number of nuclear weapons in its arsenal.  That conventional wisdom, argues Brad Roberts in The Case for Nuclear Weapons in the 21st Century, has not been informed by the experience of the United States since the Cold War in trying to adapt deterrence to a changed world or of the Obama administration to create the conditions that would allow further significant changes to U.S. nuclear policy and posture.  A CISAC affiliate, Roberts served as Deputy Assistant Secretary of Defense for Nuclear and Missile Defense Policy during the first Obama administration. He wrote the book, which draws heavily on his experience in government, during his time as a consulting professor and William J. Perry fellow at CISAC in 2014. To purchase the book, please visit: http://www.sup.org/books/title/?id=26137

Why did you write this book?

My main purpose was to reclaim the middle in the U.S. nuclear policy debate.  As in so much of the rest of our national political life, the middle has disappeared from this particular debate, leaving two deeply antagonistic camps to dominate it. One favors more disarmament now, while the other sees many enduring roles for U.S. nuclear weapons. The division didn’t matter so long as the United States could live off the investments of the Cold War.  It can no longer do so, as old weapons and delivery systems age out and expensive decisions must be made.  A coherent and centrist approach is needed to guide national choices, and this book attempts to fill that gap.

What is your main argument?

That the conditions do not now exist for the United States to safely take additional steps to further reduce the number and role of U.S. nuclear weapons. The Obama administration set out a strategy for creating those conditions in 2009, and the results have been disappointing. Russia has rejected further arms control. China has rejected further transparency.  Others have refused to join an international consensus against nuclear weapons. This experience must temper enthusiasm for the disarmament project. The conditions do not exist and are not proximate.

What is the case against nuclear weapons? And why do you think the case for nuclear weapons is more compelling?

The case against nuclear weapons has been made on many grounds:  historical (‘these are nothing more than cold war relics’), moral (‘their use in war would violate the laws of war so deterrence is immoral as well’), and prudential (‘we can’t prove that deterrence works but we can prove that these are dangerous weapons’). The case for nuclear weapons derives first and foremost from the role the United States wants to play in the world—as a security guarantor to others and a projector of power to promote stability and our values. In today’s world, without nuclear weapons, the United States could not play that role.

Can you ever imagine a scenario where the U.S. would need to use nuclear weapons again?

We don't have nuclear weapons to fight and win wars with them; we have nuclear weapons to ensure they are never used against us or our allies—in other words, for deterrence.  The President would only consider the employment of nuclear weapons in extreme circumstances when the vital interests of the United States or an ally are at risk. Though extreme, such circumstances are not implausible. The cold-war vintage bolt-from-the-blue major strike isn’t the potential problem today; rather, the problem is a regional conflict that goes badly for an adversary who then tries to escalate his way out of failed aggression against a U.S. ally. At least three nuclear-armed potential adversaries have now long studied the common problem they face:  deterring and defeating a conventionally-superior nuclear-armed major power and its allies. They have developed theories of victory built around nuclear coercion, blackmail, and brinksmanship, aimed at breaking the will of the United States and its allies, including with limited nuclear strikes to demonstrate their resolve. Our deterrence strategy requires that we have an effective ability to respond and that the threat to employ it in the circumstances they create is credible. Moreover, let us distinguish the verb “employ” from “use.” U.S. nuclear weapons are used every day to cast a shadow of doubt over the thinking of potential challengers to U.S. interests and to assure our allies. 

President Obama set out a vision for a world free of nuclear weapons at a speech in Prague in April, 2009. Does your book contradict the President’s strategic vision?

President Obama is a pragmatist and this was reflected in the Prague speech. In 2009, we took some steps to reduce the role and number of nuclear weapons and set out a plan for working with others to create the conditions for further reductions. But so long as nuclear weapons remain, the President is committed to ensuring that nuclear deterrence remains effective. Toward that end, the administration has expended considerable time, energy, and money.  This is the story of that effort and a distillation of key lessons.