She dipped her head below the surface, and in mere seconds resurfaced with a freshly plucked freshwater mussel from the riverbed with an expression of pure satisfaction on her face. Her eyes sparkled with the same childlike wonder that I had seen in many of the young explorers I’ve met over the years. But here was Jill Heinerth, a seasoned expeditionist, still brimming with curiosity and awe for the life found right in her backyard.

Seeing someone as accomplished as Jill find so much excitement and fascination in a relatively modest environment was humbling. I had assumed that after diving in places like Antarctica, the Sahara, and the volcanic lava tubes of the ocean floor, her home province would pale in comparison. But I was so wrong. Jill had chosen to return to her roots, to live near Ottawa and dedicate the remainder of her life to exploring this lesser-known cave system in this very river. For her, excitement didn’t necessarily stem from grand, exotic locations or daring encounters with flagship species – she has done all of that. Today, it was coming from the incredible ecosystems thriving just beneath the surface, often overlooked by the untrained eye.

The shallow water we waded through wasn’t your typical murky – it was tanned. Many would have thought these waters were highly polluted given their appearance. But to Jill, this was a sign of health. Here, was a living, breathing ecosystem full of unexplored life, waiting to be discovered. She encouraged me to dive down and get as close as possible to the riverbed in order to find mussels of all shapes and sizes. We were on a mission to locate the endangered ‘hickory nut mussel’, a species she explained was critical to the health of this ecosystem. I had no idea what I was looking for, but I was following Jill’s lead, trying to take in every slice of knowledge she was throwing our way. After all, getting instructions from this underwater icon was a surreal experience, especially for a relatively new diver like me. 

We had been aware of Jill’s work for some time before meeting her in person. Ever since we started considering our own journey into cave diving. She was one of those rare individuals who had carved out a career in exploration and environmental advocacy without following a conventional path. Like us, she came from a non-traditional background in marketing and art, forging her way to become a full-time underwater explorer, filmmaker, author, citizen scientist, and an Explorer in Residence at the Royal Canadian Geographical Society. Jill never asked for permission to pursue her passions, and that is something I believe resonates with many women today, including yours truly.

However, instead of discussing her past achievements, Jill wanted to focus on the now – and she was showing it to us in real time. Just a few weeks before we met up, Jill had wrapped up her latest film premiere, Diving Into the Darkness: Never Cave into Fear. The film was directed by the surprisingly young and talented Nays Baghai, who learned to cave dive specifically to document Jill’s journey. It’s already gained critical acclaim, highlighting the dangers and thrills of cave diving – a world Jill knows unlike many others. And now, we found ourselves near one of the very cave systems that she planned to spend the rest of her life exploring, and clearly had a deep emotional connection to. 

This particular cave system, part of the Ottawa River complex, is one of the most remote and challenging Jill has ever encountered. It’s so remote, in fact, that few people – even those living in nearby Ottawa – know it exists. Situated nearly two hours from the capital city, in the Whitewater region, these caves have hardly been explored, with only a handful of divers, including Jill, having dared to venture into them. Joining us that day was Cheryl Spotswood, a local adventurer and retired educator who has spent her life navigating these waters. She works alongside Jill Heinerth to help provide local knowledge in order to best tackle some of the more complicated dive days and acts as a guide in these parts. Cheryl, like Jill, is a genuine force of nature, a trailblazer who has lived every aspect of her life on her terms. Together, these two women represented a kind of fearless determination that was both inspiring and infectious. 

So, what exactly is so special about this cave system? Especially for someone who has completed over 8,000 cave dives, many of which have been in the most complex and challenging environments on earth? For Jill, this cave system represents the ultimate challenge. And a large part of why she moved back to this area was that she knew it would take a lifetime to properly explore these caves and share her findings with the world. This is a project she has undertaken in collaboration with Dr. David Sawatzky, who first explored these caves in the 1980s. It took him 15 years to map out the 10.5 kilometres of submerged passageways, with still much left unexplored. 

When Jill Heinerth first visited these caves, she was struck by how much life existed within them, which was unlike anything she had seen in all her years of diving. The caves were filled with mussels, sponges, benthic invertebrates – all working together in a natural ecosystem, untouched by invasive species or human hands. The deeper she went, the more she found, and the more fascinated she became. To her, this was a special environment, one that needed to be documented, understood, and most importantly, protected.

As Jill Heinerth pulled up each mussel, she would tell us its name, both common and scientific, such as Ligumia recta, Elliptio complanata, Lampsilis radiata, Lampsilis cardium, and Obovaria olivaria. She explained their role in the ecosystem, detailing how they filtered the water, reproduced, and contributed to the river’s health. Jill’s knowledge was encyclopedic, yet her passion was that of an artist – someone who saw beauty in the intricate details of life that many others might overlook. Without a PhD, Jill had spent her life in the field, immersing herself in the experience and collaborating with some of the most respected scientists in the world. She has always seen her role as a bridge, translating complex scientific findings into stories that resonate with a broader audience. As I stood there in the waters of the Ottawa River, it was clear that this project was the culmination of all her experiences.

Most people think of mussels as nothing more than a seafood best smothered in garlic and butter, but freshwater mussels like the ones here are different. These mussels need a collaborator, a specific fish host, to survive. The mussels filter the water, creating a healthier environment for the fish and other organisms within the watershed. The fish, in turn, help the mussels reproduce. Once a year, a female mussel will grow a lure out of her mantle that resembles a small fish. When an actual fish bites the lure, the mussel releases her larvae into the fish’s gills, where they latch on and grow, feeding on the fish’s blood serum. Eventually, they drop off and settle into the riverbed, where they continue the cycle of filtering water. In other regions, these species are in decline, and many are endangered, making their conservation critical to the health of the ecosystem. However, Jill was happy to inform us that many of these mussel species of the river were alive and thriving. 

Beyond her vast knowledge and sharp memory, what struck me most about Jill was her profound sense of urgency. She’s not just exploring for the thrill of discovery; she’s on a mission to protect this fragile ecosystem and the broader environment she’s always called home. Jill’s journey began near Lake Ontario, where she grew up observing the murky, opaque waters, which fuelled her deep connection to this region. As a child, the lake’s visibility was often limited to just a few feet/meters. As she grew up, that murkiness gave way to clearer waters, but the apparent improvement came at a steep cost. The Great Lakes, including Lake Ontario, have been severely impacted by invasive species like zebra and quagga mussels. These non-native bivalves, originating from the Caspian and Black Sea regions, were introduced via ballast water from transoceanic ships. Once the water was released into the lakes, they spread rapidly, attaching themselves to any solid surface – from intake pipes to the shells of native mussels. While their filtration makes the water appear cleaner, it has also led to the collapse of native species, Unionid mussels as they are called, which have been outcompeted for food and space.

Jill took us diving in Lake Ontario to witness this contrast firsthand. The water, once teaming with life, was eerily quiet and sterile in appearance. There was not a single native mussel in sight, their populations decimated by the relentless spread of the invasive species. The food web in many areas here had fully collapsed, leaving behind an ecosystem that, while seemingly clean, was struggling to sustain itself in its most natural and organic way. The once-thriving communities of fish, invertebrates, and plant life had been replaced by a monoculture of zebra and quagga mussels.

On the other hand, the Ottawa River remains what Jill Heinerth describes as a ‘protected Eden’. The river’s tannic-stained waters, darkened by organic matter from the surrounding forests, might seem less appealing than the clear lakes. However, to the trained eye, this is the sign of a healthy, functioning ecosystem, a reminder of what the Great Lakes once were and could become again with proper restoration. Jill sees the Ottawa River as a hopeful blueprint for the revival of the Great Lakes and other damaged waterways worldwide.

In recent years, the urgency in Jill’s work around THIS area has only grown more intense. This is especially true with looming threats like the proposed Chalk River Nuclear Labs disposal facility, which is planned for construction near the river’s edge, just upstream from the cave system. Jill has teamed up with Dr. Andre Martel, Canada’s leading malacologist, to tackle this challenge. Dr. Martel, an expert in freshwater mussels, brings a deep scientific understanding of these vital species, which play a crucial role in the river’s ecosystem. His academic expertise is the perfect complement to Jill’s hands-on experience and exploration skills.

While Andre focuses on the detailed scientific analysis, identifying species, and understanding their role within the ecosystem, Jill’s role is to explore the difficult-to-reach areas of the caves, bringing back data, images, and observations that Andre can analyse. She does this by documenting her findings in a journal, drawing everything she sees by hand. Flipping through her books, she was incredibly precise in how she sketched each of her findings, proving that she could find a way to tie art back into her exploration work in ways one wouldn’t immediately suspect! On top of that, Jill’s diving skills allow her to access parts of the cave system that are otherwise unreachable, documenting the life within these submerged passageways, mapping new sections, and observing firsthand the conditions and challenges these ecosystems face.

Together, they are a formidable team, tapping into both sides of the brain through their respective strengths. Jill’s ability to navigate and chart the hidden parts of this underwater environment, combined with Andre’s scientific expertise, allows them to create a comprehensive picture of what sits below. Their work is not just about protecting a single river, but rather about understanding and communicating the interconnectedness of all the water systems in the region. The Ottawa River feeds into the St. Lawrence River, which eventually flows into the Atlantic Ocean. The health of these waters affects the health of the entire planet, making their mission not just locally, but globally significant. 

My time with Jill Heinerth in the remoteness of Ontario wasn’t just an exploration of an underwater world; it was a masterclass in curiosity, resilience, and the relentless pursuit of knowledge. Watching a seasoned explorer with decades of experience find joy and purpose in every dive and even the tiniest specimens, reminded me that adventure isn’t about how far you travel, but how deeply you engage with the world around you. Jill’s work, mapping the hidden ecosystems beneath the Ottawa River and fighting to protect them, is a testament to the power of following your passion without asking for anyone’s permission. Her journey is a call to all of us, especially women, to dive into your pursuits head first, and never stop pushing boundaries, whether it’s the depths of a cave, a new career, or uncharted territories right in our own backyards. In her words: “You never know where that first step might lead, but it could be the beginning of a lifelong adventure, and one with the power to change the world.”