e put the anesthetic in the water. Then we have the animal breathe that water, which means we use a
pump to flow the water over the gills.”
“Of a fish?” I ask.
“Sure!” he smiles. “Just like people, a ray needs to breathe while under anesthesia.”
Oh, right! A fish breathes water.
I’m standing in a bright, clean-swept atrium in the A. Watson Armour III Center for Animal Health and Welfare at Shedd Aquarium in Chicago with Dr. William Van Bonn, Vice President for Animal Health. In front of us is a large picture window that looks on to a veterinary operating room.
I’d been gawking at a photo on the wall next to it. In the photo Van Bonn and Dr. Trevor Zachariah are doing surgery on a cownose ray. The ray is flat on its back on the operating table—a “wet table” especially designed so running water can flow over the ray’s gills. Rays, like sharks, skates, and sawfish, are classified as fish. The gill slits are on the lower side of their cartilaginous fins.
“She’d contracted an infection after giving birth and needed surgery,” Van Bonn explained. Females generally give birth to just one pup after a period of 10 to 12 months of gestation. In the womb, the pup’s wing-like fins are wrapped around it like a burrito. They unfold at birth.
“Let’s go have a look at her,” he beams. When he opens the door the sound of voices rushes in. The aquarium is packed with visitors, brimming with animated conversation. I follow Van Bonn to an enormous aquarium, a 90,000 gallon circular tank which is a Caribbean reef exhibit. Instead of a flat, rectangular view, the exhibit allows visitors to walk the circle of its periphery and view the inhabitants from innumerable angles.
We stand still and wait patiently for a cownose ray to swim by. Some blue fusilers—snapper-shaped fish—swim by. Then an angelfish. Hogfish, pufferfish, sea turtle. My eyes are peeled for a ray with a wingspan about a yard wide with a brown back and pearl-white underbelly. A ray just like that approaches, gracefully swishing its fins.
“There she is!” I blurt out.
“Nope, not her.”
When I see a cownose ray, I see “a cownose ray.” But Van Bonn? He sees a specific individual.
Another ray comes around the corner.
“There’s the gal!” he grins. “If you look really close you can actually see some scars from the surgery.”
Van Bonn steps closer to the glass of the aquarium. The ray makes a slow motion underwater back flip with her cape-like fins. Van Bonn eyes her with a winsome smile. Nothing like the satisfaction of a surgeon in the presence of a fully-recovered patient.
I’d come to interview Van Bonn because he was heading up the Shedd Aquarium Microbiome Project, which studies microbiomes in aquarium environments and their impact on the inhabitants of those habitats.
“If you break the word microbiome down,” Van Bonn explains, “micro means tiny, bio means living, and ome means community. We’re talking about microscopic living communities.”
We know microrganisms dramatically affect human health. Probiotics may ease indigestion after taking antibiotics, which sometimes kill off not only the harmful bacteria in our bodies, but the ones that help us digest food too. Each of our bodies is quite literally an ecosystem supported by communities of organisms—in our GI tracts, ears, skin, and saliva—many of which are essential to good health. Most of us are more aware of the consequences of an imbalance in the ecosystem of our body, such as antibiotic-resistant bacteria that can kill us.
But why study aquatic microbiomes?
Same thing. The upset of microbial communities—lack of balance—is having devastating effects on our seas and waterways. Aquatic dead zone, caused primarily by fertilizer runoff, are areas in which there is such a low oxygen concentration that many organisms suffocate and die. These dead zones are expanding. The largest one in the Gulf of Mexico is 8,500 square miles, roughly the size of the state of New Jersey. And not only does this have consequences for the fish that breathe water, it has consequences for our atmosphere: over half the oxygen in every breath we take comes from marine microbes, plants and algae.
Toxic algae blooms are another result of microbiome imbalances. The algae bloom that currently stretches from southern California to the Alaska has triggered fisheries closures. The toxin, domoic acid, causes amnesiac shellfish poisoning in human beings. The chilling list of symptoms leaves no doubt that fisheries should be closed when it’s a threat—seizures, brain damage, and memory loss. The toxin is responsible for the deaths of thousands of marine mammals and sea birds.
Minimizing pollution and mitigating climate change are key solutions. But understanding the mechanisms of those imbalances, so we can help restore healthy aquatic microbial communities is also key. So what is a balanced aquatic ecosystem? What is healthy water?
The answer is undergoing re-definition and that’s what the Microbiome Project’s work is all about. “Healthy water” had traditionally meant “sterilized” water, devoid of germs. Now we are learning that healthy water entails a balanced microbiome of organisms. But what exactly do those balanced microbiomes look like? That’s the focus of the research and it will shed light on everything from marine ecosystems, lakes and waterways to water treatment facilities.
Van Bonn leads me out a side door to a large covered outdoor pool surrounded by visitors—a touch pool. A dozen or so cownose rays swim through the shallow water like a flock of aquatic birds. The visitors rinse their hands to protect the health of the rays, roll up their sleeves and gently lower their hands into the pool. When a ray comes and touches them, they squeal with delight.
“I like to think of the earth as aquarium earth,” Van Bonn explains. “There’s no doubt, our planet is a controlled environment.” Van Bonn is referring to the fact our planet has only so much water and other resources to offer. By virtue of humanity’s vastly expanded influence, we need to be stewards of those resources.
“Aquariums are great test platforms to study the impact of human activity on aquatic ecosystems,” Van Bonn continues. “We have a masters student, Dr. Jimmy Johnson, who is studying the microbiome of this system. He starts by collecting samples from when there is nothing but water in here, then when we get the filter up and running, then when we put the cownose rays in there and then when we let people come in. He’s looking at the health parameters of the rays. What changes? What drives those changes? What does it mean for their health? He’s looking not only at the microbiome of the water, but the microbiome associated with the rays—their GI tract, skin, and gill microbiomes.”
Van Bonn takes me to one of their clinical labs where the Senior Clinical Laboratory Technician, Frank Oliaro, is doing a post-mortem on an angelfish. Oliaro had taken a sample from behind it’s gills to look at under a microscope.
I put both eyes to the eyepieces of the microscope. The tiny swab of gill tissue is bursting with activity, layers upon layers of blue-violet particles swimming: the microbiome behind the gills. Some of the moving particles are circular, some elongated.
“Those are actually protozoa.” Van Bonn is looking at the same swab on a computer display hooked up to the microscope. “Protozoa are little living animals. They are many times bigger than bacteria itself. In fact they are probably grazing on bacteria.”
“Would you see that normally?”
“Yeah, but it’s all about balance. If you see a couple, you would expect to see that. The question is, does that represent what’s happening in the habitat? Or is this after the animal has died?”
To figure that out they’d look at the other animals in that habitat and samples of the water. Each step in this research drives discoveries that can support human health and the health of our ecosystems. “We look for what things are under the control of the people that make a difference for the entire system, starting with the microscopic critters that call the water home,” Van Bonn explains. “And how can we do a better job of taking care of them?”
The project uses a wide range of data—from parameters like PH, temperature, salinity, ammonia, ionized calcium to DNA sequencing—to analyze the potential impact of changes in each of these on the system's health. “If you can understand processes at the level of the built-environment, like an aquarium,” Vann Bonn tells me, “you can back up and extrapolate outward from one of our small systems, to larger systems, to lakes, to the oceans, to the planet.”
Before I left that day I paused by the circular aquarium where Van Bonn and I had waited for the cownose ray that had been Van Bonn’s patient. This time I recognized her when she swished by.
I blinked and imagined I could see the microscopic life that made this water habitable, as if I could don a pair of microscopic goggles which could see through bodies like x-rays, revealing the minute creatures in the water and inside that cownose ray and my own body for that matter: all of the microscopic life that makes our lives possible.
To have a sustainable relationship with our planet we need to understand the microscopic organisms that support the armature of life. The seas and our waterways are not as vast as we used to think: they are not limitless. But our capacity to understand life and to act in a way that fosters life, rather than destroys it, that potential is just beginning to be explored.
How Microbiomes are Crucial to Healthy Water and a Healthy Planet
By Liz Cunningham, author of Ocean Country:
One Woman’s Voyage from Peril to
Hope in Her Quest to Save the Seas
78 - SEVENSEAS