Mike deGruy and the Alien World of Underwater Brine Pools: A Cinematic Legacy

“Wait a minute! I’m already underwater! How can there be a lake?!” These were the astonished words of Mike deGruy, the legendary underwater cinematographer, as he encountered one of nature’s most bizarre phenomena during filming for BBC’s “The Blue Planet” series. What he discovered in the depths of the Gulf of Mexico would captivate audiences worldwide and showcase a rarely seen wonder of our oceans – underwater brine pools.

As deGruy’s submersible approached this strange underwater lake, something unexpected happened. The vessel, designed to explore the deepest ocean trenches, literally bounced off the surface of this dense, briny water. The submersible created ripples across what appeared to be an underwater shoreline, defying our understanding of underwater physics and revealing a hidden world few humans had ever witnessed.

The Science Behind Underwater Lakes: Brine Pool Formation

Brine pools are extraordinary formations that occur when water seeps through large salt deposits beneath the seafloor. As this water dissolves the salt, it becomes incredibly saline – up to five times saltier than normal seawater. This hypersaline water is so dense that it sinks and collects in depressions on the ocean floor, creating what appears to be underwater lakes complete with shorelines and waves.

What makes these pools particularly fascinating is the sharp boundary between the brine and the surrounding seawater. This boundary layer, called a halocline, is so distinct that it reflects light like a mirror and creates the illusion of a water surface – despite being hundreds or thousands of feet underwater. The density difference is so extreme that submarines and submersibles, like deGruy’s, cannot easily penetrate this layer.

The halocline creates a distinct boundary between normal seawater and the dense brine, appearing like a mirror-like surface underwater.

These underwater lakes aren’t just visual curiosities – they’re unique ecosystems. The extreme salinity makes the pools themselves toxic to most marine life, but the edges teem with specialized organisms that have adapted to these harsh conditions. Mussels, crustaceans, and specialized bacteria cluster around these pools, creating oasis-like environments in otherwise sparse deep-sea landscapes.

Mike deGruy’s Brine Pool Exploration: A Clarification

Mike deGruy’s submersible approaching a brine pool during filming for BBC’s “The Blue Planet” series.

While Mike deGruy’s footage of brine pools brought these fascinating formations into the public consciousness, it’s important to note that he was not the first to discover them. Scientists had documented brine pools years earlier in various locations, including the Red Sea and other parts of the Gulf of Mexico. What made deGruy’s contribution significant was his ability to capture these phenomena in a way that made them accessible and awe-inspiring to audiences worldwide.

During his interview about the experience, deGruy’s enthusiasm was palpable: “The most amazing thing… anywhere is when I went to the Gulf of Mexico, for Blue Planet, to film the Underwater Lake… I’m like ‘Wait a minute! I’m already underwater! How can there be a lake?!’ But it was! Fantastic area! Fantastic! I have no idea what’s in the lake…”

The edges of brine pools create unique ecosystems where specialized organisms thrive despite the extreme conditions.

What deGruy and his crew attempted next demonstrates why he was such a pioneering filmmaker. They tried to descend into the brine lake itself – a potentially dangerous endeavor given the toxic nature of the hypersaline water. However, the submersible literally bounced off the surface, sending ripples to the lake’s “shore” due to the extreme density difference between the brine and normal seawater.

This moment, captured on film, became one of the most memorable sequences in underwater documentary history, showcasing both the strange physics of brine pools and deGruy’s adventurous spirit in pursuing unprecedented footage.

Beyond Brine Pools: Mike deGruy’s Remarkable Career

First Footage of Elusive Deep-Sea Creatures

Mike deGruy was part of the team that captured the first footage of the elusive vampire squid.

Among deGruy’s most significant achievements was being part of the team that captured the first footage of several elusive deep-sea creatures. His work documenting the vampire squid and the nautilus brought these mysterious animals into public view for the first time. These pioneering visual records have been invaluable to marine biologists studying these rarely seen species.

As noted by the Scenic 98 Coastal publication, “He was a member of many deep-sea expeditions and was part of the team that first filmed the vampire squid and the nautilus.” These achievements required not only technical diving expertise but also immense patience and an intimate understanding of marine life behavior.

In his captivating TED Talk “Hooked by an Octopus,” deGruy shares his passion for ocean exploration and the fascinating creatures he encountered. His storytelling ability made complex marine biology accessible and engaging to general audiences, helping to foster greater appreciation for ocean conservation.

Exploring Hydrothermal Vents

deGruy diving near hydrothermal vents, documenting these extreme environments and their unique ecosystems.

Another remarkable aspect of deGruy’s career was his exploration of hydrothermal vents in both the Atlantic and Pacific Oceans. These underwater geothermal features, where superheated water erupts from the seafloor, host some of Earth’s most extreme ecosystems. Organisms living around these vents have evolved to survive in conditions that would be lethal to most life forms.

deGruy’s footage of these alien-like environments revealed a world where life thrives without sunlight, instead deriving energy from chemical reactions in a process called chemosynthesis. His work helped scientists better understand these unique ecosystems and their importance to ocean biodiversity.

Collaboration with James Cameron

Mike deGruy collaborated with director James Cameron on several deep-sea projects, including Titanic exploration.

deGruy’s expertise in underwater cinematography led to a fruitful collaboration with director James Cameron. He was instrumental in filming the wreck of the Titanic for Cameron’s projects, including the documentary “Last Mysteries of the Titanic” (2005). deGruy once quipped that he had “eaten more meals on the deck of the Titanic than the passengers of the doomed vessel had eaten before the iceberg.”

This partnership extended to Cameron’s ambitious Deepsea Challenge expedition, which aimed to explore the Mariana Trench, the deepest part of the world’s oceans. Though deGruy tragically passed away before the expedition’s completion, his contributions to deep-sea filming techniques were invaluable to the project’s success.

After deGruy’s death, Cameron paid tribute to him, saying: “Mike and Andrew were like family to me. They were my deep-sea brothers, and both were true explorers who did extraordinary things and went places no human being has been.”

A Lasting Legacy: Mike deGruy’s Impact on Ocean Conservation

In his later years, deGruy became increasingly focused on ocean conservation and environmental activism.

The Deepwater Horizon oil spill in 2010 marked a turning point in deGruy’s career. Having grown up diving in the Gulf of Mexico, he was deeply affected by the environmental disaster. According to Scenic 98 Coastal, “The BP oil spill threatened the very waters Mike grew up in, and he passionately set about using all his influence to protect and preserve the waters he loved so much.”

This event catalyzed his shift toward environmental activism, using his filmmaking skills to raise awareness about ocean conservation issues. He returned to the Gulf multiple times during the spill, documenting its impact and working on a documentary about the disaster.

deGruy returned to the Gulf of Mexico multiple times to document the devastating effects of the Deepwater Horizon oil spill.

Tragically, Mike deGruy’s remarkable life was cut short on February 4, 2012, when he died in a helicopter crash in Australia at the age of 60. He was preparing to film for another documentary with James Cameron when the accident occurred. The crash also claimed the life of Australian filmmaker Andrew Wight, who was piloting the helicopter.

Following his death, deGruy’s wife and film partner, Mimi, produced and directed “Diving Deep: The Life and Times of Mike deGruy,” a documentary celebrating his extraordinary contributions to underwater filmmaking and ocean conservation. The film has won several awards and continues to inspire new generations of ocean explorers and conservationists.

Exploring the Depths: Mike deGruy’s Enduring Inspiration

Research continues at brine pool sites in the Gulf of Mexico, building upon the awareness created by deGruy’s pioneering footage.

Mike deGruy’s work with brine pools represents just one chapter in an extraordinary career dedicated to revealing the ocean’s mysteries. While he wasn’t the first to discover these underwater lakes, his cinematic portrayal of them brought these strange formations into public consciousness and inspired countless viewers to appreciate the wonders of our oceans.

His legacy lives on not only through his groundbreaking footage but also through the continued exploration of the deep sea. Scientists continue to study brine pools, hydrothermal vents, and other extreme environments, building upon the awareness and wonder that deGruy helped create.

Perhaps the most fitting tribute to Mike deGruy comes from his own words during his TED Talk: “The ocean is in trouble. I’ve seen a lot of places, and there’s evidence of this everywhere. But there’s also hope.” Through his work, he showed us both the beauty worth protecting and the environmental challenges we must address – a dual legacy that continues to inspire ocean conservation efforts worldwide.