The Pacific Tide: The Secret World of Dolphin Feces
California’s Pacific coast is one of the most biodiverse and abundant ecosystems worldwide teaming with almost 2000 species of microorganisms, plants, fish, marine mammals, turtles, invertebrates, and seabirds supported by a Mediterranean climate. Its famous offshore, underwater, and coastal rock formations date back to the Cretaceous period and help subsidize this special bionetwork making the state’s ocean waters and sea life sacred and unique. Unfortunately, California’s precious coastal ecosystem also faces massive threats in the vein of climate change/global warming, the devastation of kelp forests, ocean acidification, algal blooms, and habitat destruction; sounding the alarm for the time-sensitive need for human intervention, conservation management, and awareness.
The Pacific Tide series highlights monthly oceanic events occurring on the California coast and/or portraits important species who call the Pacific coastline waters home emphasizing the importance of conserving this critical ecosystem.
In this month’s installment of The Pacific Tide, we introduce the not-so-glamourous but incredibly astonishing subject of dolphin poop! Dolphin stool is a leading solution against climate change helping absorb Co2 through the Cetacean Carbon Sequestration Cycle; single-handedly fighting greenhouse gases. Also explore with us while we dive among California’s Pacific coral reefs flourishing from under the nutrient benefits of dolphin poop plumes.
Discover the U.S. Navy’s dolphin fleet at the Navy Marine Mammal Program and the groundbreaking procedure of dolphin fecal microbiota transplants (FMTs) spearheaded by Cardiology Veterinary Consultant, Dr. Barbara Linnehan, using dolphin-to-dolphin trans-rectal transplants to entirely cure dolphins suffering from gastrointestinal disease and maligned gut microbiome flora communities.
California: The Dolphin Capital of the World
The coastal beaches of California are undisputedly a gorgeous spectacle filled with palm trees, rolling sands, rocky cliff outcrops, dazzling sunsets, and sparkling, blue waters topped with white-capped waves; being well-worthy of its vacation destination title and postcard images. If this visual tapestry wasn’t heavenly enough; it becomes museum-quality when California’s most eminent marine mammals are spotted leaping into the air with the sun glistening off their wet, rubbery skin: dolphins. Renowned for their intellect, problem-solving skills, cheerful disposition, playfulness, and almost human-like social behavior; these Cetaceans (the scientific order including dolphins and whales) have been a ‘fan-favorite’ for generations, from the iconic “Flipper” television sitcom to the Lisa Frank school supplies pasted with colorful dolphin images owned by all 80s and 90s school children and every other derivation imaginable.
California is the dolphin capital of the world, home to approximately one million dolphins up and down the Golden Coast. With more dolphins than Alaska, Hawaii and Florida combined; California has a greater density of dolphins per square mile than anywhere on Earth with 12 species of dolphins enjoying the west coast’s Pacific Blue. California’s primary dolphin species – Bottlenose, Common, Pacific White-Sided and Risso’s – are frequently observed swimming in families, pods and mega-pods ranging from 50 to 10,000 dolphins stampeding up to 200 miles daily at a minimum speed of 30 miles per hour with acrobatics added for flair. These California dolphins grow between 8 and 13 feet and recharge their energy bank by consuming 4 to 6% of their body weight, per day.
With such a large appetite; dolphins can only thrive in oceans abundant in their favorite meals of a plump fish or slimy squid. California’s Pacific Ocean is the ideal sustenance grocery store for dolphins; ever-stocked with their favorite snacks which is why dolphins can be frequently spotted in both shallow California coastal waters and in the more temperate underwater canyon upwellings of the deeper seas.
Dolphins serve a critical role in Pacific Ocean ecosystems being more than just a ‘cute’ gymnast in the oceanic Olympic games; as they are a sentinel species biomarker highlighting the health grade of the marine environment: a higher population of dolphins in the Pacific means the ocean is salubrious and teeming with food sources. Dolphins don’t just ‘take’, however, but also ‘give’ by single-handedly improving their watery home by creating a positive bio-cycle: greater number of dolphins → resultant of food-heavy ocean → resultant of large population of dolphins. How do dolphins act as a superhero of the ocean? It isn’t by donning a colorful cape but rather by means of something less glamorous: their fecal excrement.
Is Dolphin Poop the Answer to Amend Climate Change?
With upwards of a million dolphins swimming in California’s Pacific waters; this means a LOT of dolphin fecal matter floating in this giant toilet moonlighting as one of the ocean’s most important ecosystem players. Dolphin excrement is rich in nutrients particularly nitrogen, iron, and phosphorus which kick-starts the process of carbon sequestration: the absorption of the over-saturation of carbon dioxide that is the villain behind global warming and climate change. This powerful trifecta recipe in dolphin stool is the favorite metabolic nutrient food source of phytoplankton which acts as the trees of the ocean by undergoing photosynthesis and absorbing the pesky carbon. Matthew Savoca, a Marine Scientist at California’s Stanford University plainly describes phytoplankton as, “When they grow… they’re sucking in carbon dioxide and incorporating that into their cells”. When phytoplankton expires in death; the stored carbon is buried deep within the ocean’s sea beds thus diminishing the volume at the surface attempting to wreak havoc. California’s dolphin headquarters are a prime producer of this beneficial fecal matter with a single dolphin pod estimated to produce upwards of 634 pounds of nitrogen a year. Multiply that by California’s million-dolphin population and you will find that this Cetacean Carbon Cycle is not just benefiting oceanic ecosystem resilience and habitat productivity; but is also fighting global warming by regulating Co2.
Dolphins aren’t bashful with bathroom habits preferring to defecate at the surface with their carbon crusader poop mostly consisting of soft stool clouding the water in a fecal plume. This ‘Dolphin Tap’, coined by scientists, fortifies the carbon absorption cycle with dolphin excrement feeding phytoplankton, zooplankton (such as krill) eating the phytoplankton, fish in turn consuming krill, and finally dolphins imbibing on the fish; basically, making dolphins the regenerators of their own food chain while reducing greenhouse gases. This induction of the Dolphin Tap rightfully earns dolphins their moniker as ‘ecosystem engineers’ by means of reshaping their marine environment physically and biologically simply by being alive.
Dolphin poop has been found to be beneficial in combating climate change and in restoring biodiversity; scientists and environmental policymakers are exploring the process of ‘ocean seeding’ to mitigate climate change – biomass ocean regeneration through the dissemination of artificial dolphin poop. Yes, artificial poop. This mock poop behaves akin to natural dolphin stool with identical minerals feeding the phytoplankton at the starting line of the carbon sequestration cycle. Even though this imitation feces is organically sound, using rice husks loaded with the perfect formula of nitrogen, iron, and phosphorus; ocean seeding is still in its infancy, and unknown in the extent of any negative side effects such as ocean deoxygenation. Richard Sabin, the Principal Curator of Mammals at the Natural History Museum in London, England cautions, “'It requires careful research as it's a big step to release detritus of any kind, including nutrient-rich types, into the ocean to make sure that the balance of nutrients and penetration of sunlight isn't adversely affected.”
California’s dolphins are already working to save the planet by means of Co2 reduction through their fecal matter but a hero never rests when there is a cry for help; especially when the signal is coming from within the ocean, itself.
California’s Hidden Treasure Trove of Corals
If you’re planning your next vacation with the itinerary to swim among alluring, colorful coral reefs; you likely assume you need to book a plane ticket to a lush, tropical island or most famously: the Great Barrier Reef. What if I told you that you can find coral reefs in more temperate waters edging the entire California coastline? It might sound like nonsense; but it’s true! California’s corals are the direct definition of the adage of a ‘hidden gem’ even though the state’s shoreline is abundant in these underwater jewels.
Traditional corals reside in shallow, warm waters growing and expanding through the process of photosynthesis thriving off the sun’s rays and symbiotic relationships with algal communities. In contrast, California’s reefs are primarily deep-sea corals found at a depth of 10 to 10,000 feet existing on a mineral-nutrient diet rather than solar power which fails to penetrate these depths. Although less famous; California’s coral reefs are a key asset to the Pacific oceanic ecosystem and even boast rare corals that are native to the state’s waters resembling a homage to a candy store with Strawberry Anemone, Bubble Gum Coral, Purple Hydrocoral, and Barrel Sponges sounding more like dessert than sea creatures. Coral reefs can be found parallel to the entire shoreline with the largest reefs living off Catalina Island, another 80 miles off the Monterey coast at the Monterey Bay National Marine Sanctuary (Davidson Seamount), Cordell Bank National Marine Sanctuary, and the mighty Sur Ridge in Central California’s waters.
California’s corals are more than just a Candyland board game and are essential marine ecosystem players being the adhesive holding together the sea beds and providing a habitat for sea plants and animals. If these reefs were to become metaphorically bulldozed; California’s coastal waters would suffer an identity crisis with the extinction of tide pools, kelp forests, and in turn: marine animals and plants. These corals are of such importance that lawmakers have zoned each California reef as a marine sanctuary area and prohibit the alteration, destruction, or taking of the precious California corals.
Corals have existed off the shores of California for thousands of years with many of today’s reef generations being formed over multiple centuries. Age doesn’t protect these corals from modern-day damage, global warming, or being highly threatened by ocean acidification and bottom-trawling fishing. Central California’s waters are characteristically low in pH hastening acidification and the destruction of the bio-diversity of its corals. Humans are also ill-fated for these gems of the sea with scientists finding evidence of pesticides, trash, ghost fishing gear, anchors, and toxic chemicals at a depth of 12,000 feet testing the resilience of these mighty but fragile reefs. "The California coast could be considered the front line for ocean acidification damage, within 50 years, and certainly by the end of the century. As ocean acidification due to our C02 emissions intensifies along this coast, those corals are gonna have a hard time," clarifies Jim Barry, a marine biologist working at California’s Monterey Bay Aquarium Research Institute. Scientists, ocean conservationists, California oceanic restorationists, and lawmakers have worked in tandem to protect and restore corals by implementing artificial rock reefs up-and-down the coast dating back to as early as 1958. Although these efforts are celebrated; the real guardians of corals aren’t manmade but a bit closer to home…You guessed it: dolphin poop!
Dolphin Poop: The Knight in Shining Armor to Coral Reefs
The cornucopia of corals in California’s coastal waters is increasingly threatened by rising water temperatures, elevated levels of carbon, ocean acidification, and man-made stressors such as overfishing causing an urgent level of panic among marine biologists and ocean conservationists. These colorful relatives of jellyfish and sea anemones are critical to California’s oceanic ecosystem in support of biodiversity and seabed infrastructure. Corals have an evolutionary flaw of being anemic of phosphorus and nitrogen – two key nutrients they absolutely require to flourish and grow. In swoop the dolphins with their superpower feces that are rich in this coral cocktail. California’s dolphins are creatures of habit with regimented schedules opting to spend extended periods of time ‘resting’ in sheltered parts of the sea before venturing in the pursuit of the hunt or play. Where do dolphins like to metaphorically spend a lazy morning and conserve their energy? In the peaceful, undisturbed deep-sea corals of the Pacific. During this respite period, these dolphin pods defecate frequently providing the exact nutrients that corals desperately demand making dolphin poop a vital ally in coral maintenance and restoration. Scientists have even discovered that dolphins return to the coral habitats after the hunt to digest their prey which means even more pool plumes gifted to the corals solving reef grief.
Marine studies have concluded evidence of dolphins being consistent nutrient transporters to coral communities with data collected between 2013 and 2022 showing that a single dolphin excretes almost half a pound of beneficial poop a day (81 pounds a year) and spends 36% of their waking hours in coral reefs. Extended to pods, 3000/5300 pounds of dolphin nutrient waste is absorbed directly by corals, annually.
In order to protect California corals; it is vital to sequentially protect dolphins with their savior poop. Dolphins are the chief marine species to encounter human activity exposure 82% of the day spread across tourism, boats, freight vessels, fishing, and even offshore drilling. Marine mammal advocates stress the importance of passing dolphin-protection policies against human-centric threats in order to maintain their benefits to coral (and oceanic) ecosystems. The National Oceanic and Atmospheric Administration (NOAA) upheld a governing law in Hawaii declaring a 50-yard approach limit to spinner dolphins (who have been proven to protect and restore Hawaii’s corals) within two nautical miles of the shoreline. California’s marine scientists and activists seek similar protections for the Golden State’s cetaceans.
The Healing Power of Dolphin Poop Transplants
You’ve heard of Navy SEALs, but have you heard of Navy Dolphins? Bottlenose dolphins, that is! In 1959, the United States Navy founded the ‘Marine Mammal Program’ under the tutelage of the Reconnaissance and Interdiction Division at the Naval Information Warfare Center in Point Loma (San Diego), California. This program trains bottlenose dolphins (and California sea lions) to participate in U.S. Navy missions including the detection of undersea mines, the attachment of recovery lines, and even James Bond-esque security detail for the recognition of unauthorized or suspected ‘enemies’ in California’s coastal waters. If protecting the California shoreswasn’t heroic enough; the U.S. Navy dolphin fleet also facilitated the discovery of a marine mammal medical breakthrough using none other than their amazing poop!
Dr. Barbara Linnehan, the Navy Marine Mammal Program’s Cardiology Veterinary Consultant was serving in her role as the Director of Animal Health & Welfare (2022- 2025) studying the delicate gut microbiomes of the dolphin fleet; when she documented dolphins suffering from gastrointestinal infirmities not responding to standard veterinary antibiotics. A dolphin’s intestinal system and gut microbiome host 80% of its immune system working in cahoots with the rest of the dolphin’s organs to keep overall health, in check. Dr. Linnehan was familiar with the practice of transplanting fecal stool from a healthy human host to that of a gastro-maligned recipient better known as fecal microbiota transplants (FMTs); and it dawned on her that fecal transplants could potentially be replicated among cetaceans. Linnehan and her veterinary team spearheaded a groundbreaking dolphin-to-dolphin fecal transplant resulting in the complete recovery of the gastrointestinal suffering of the ailing dolphin.
To explore this new field of dolphin fecal microbiota transplants; Linnehan teamed with Sho Kodera of the Gilbert Lab at the Center for Marine Biotechnology and Biomedicine at University of San Diego’s Scripps Institution of Oceanography to conduct a first-of-its-kind comprehensive study and implementation of dolphin FMTs. From January 2019 to February 2022, scientists transplanted stools collected from healthy dolphin donors in California’s Navy Marine Mammal Program to dolphins with poor gastrointestinal health before sequencing the gut microbiomes and authenticating signs of the re-growth and recuperation of dolphin gut flora. The team performed dolphin FMTs trans-rectally using eight healthy dolphin host donors with the transplants resulting in the full recoveries of all recipient dolphins with gastrointestinal disease and recuperation of the diversity of gut microbial communities even in those dolphins previously resistant to medication. The gut microbiomes of recipient dolphins post-transplant were found to resemble the healthy donor and successfully maintained positive gut levels even two years after the procedure.
Linnehan’s team even secured a ‘dolphin bank’ of logged dolphin poop available for future emergency dolphin FMTs. Think of it as a dolphin pharmacy, if you will. Dr. Linnehan explains, “During the project, we also came up with an effective protocol for banking healthy donor dolphin feces for later use. This has proven beneficial so that when an FMT is needed we have a healthy dolphin stool bank to pull from”. The dolphin fecal microbiota transplant study also investigated procedural methods such as using fresh versus frozen dolphin feces, rectal transplants or oral supplements, and a single FMT or a series of transplants in order to create a solid methodology for future dolphin fecal microbiota transplants.
Dolphin FMTs not only emphasize the benefit of dolphin stool but have also piloted an alternative treatment for cetaceans with gastrointestinal disease. Although primarily beneficial, veterinary medication has been found to destroy both ‘good and bad’ dolphin gut microbial flora preventing full recovery and regrowth. Dolphin FMTs avoid this pitfall and offer an encouraging new treatment plan. “This work is important to the veterinary community because it highlights a therapeutic option other than antibiotics to effectively treat gastrointestinal diseases in cetaceans, and describes a safe and effective protocol to alter the gut microbiome in animals with dysbiosis,” Dr Linnehan asserted.
The next time you think of feces as ‘gross’; remember that dolphins are using their stool to fight climate change and maintain oceanic ecosystems, ‘feed’ and restore coral reefs, and heal the gut health of fellow cetaceans through trans-rectal transplants. The power of dolphin poop!
Directories/Credits
1: “Get to Know Common Dolphins and the Dolphin Stampede”, Written by Unknown. Published on Unknown Date by Captain Dave’s Dolphin Safari
2: “Common Dolphin”, Written by Unknown. Published on Unknown Date by Orange County Outdoors
3: “California is a Dolphin Paradise”, Written by Erik Olsen. Published on February 13, 2023, by California Curated
4: “Five Different Types of Dolphins in Dana Point”, Written by Unknown. Published on Unknown Date by Captain Dave’s Dolphin Safari
5: The Dolphin Tap: Assessing the Ecosystem Role of Spinner Dolphins in Supplying Nutrients to Coral Reefs in Maui Nui, Hawai’i, Written by Unknown. Published on February 13, 2026, by Pacific Whale Foundation
6: “Nutrient-Rich Dolphin Poop Could Help Save Damaged Coral Reef”, Written by Nidhi Goyal. Published on July 12th, 2022 by Industry Tap into News
7: “Why Cetaceans”, Written by Unknown. Published on Unknown Date by World Cetacean Alliance
8: “‘Ocean Gardeners’: How Whale Poop Helps Fight Climate Change”, Written by Asiye Latife Yilmaz. Published on June 5, 2026, by Anadolu Ajansı News
9: “Artificial Whale Poo Could Help Restore Ocean Biodiversity”, Written by James Ashworth. Published on March 9, 2022, by United Kingdom Natural History Museum
10: The Dolphin Tap: Assessing the Ecosystem Role of Spinner Dolphins in Supplying Nutrients to Coral Reefs in Maui Nui, Hawai’i, Written by Grace L, Olson, Shannon M. Barber-Meyer, Jens J. Currie. Published on January 14, 2026, by Frontiers in Mammal Science
11: “Dolphin Poop Helps Save Coral Reefs”, Written by Cathy Brown. Published on August 22, 2022, by Good Nature
12: “How Dolphin Poop Could Help Save Damaged Coral Reef”, Written by Talker News. Published in July 6, 2022 by Talker Newshttps://talker.news/2022/07/06/how-dolphin-poop-could-help-save-damaged-coral-reef/
13: “Dolphin Poo Could Be Key Ingredient in Coral Reef Survival”, Written by Ethan Freedman. Published on July 7, 2022, by The Independent
14: “Deep-Sea Coral Habitat”, Written by Unknown. Published on Unknown Date by Smithsonian National Museum of Natural History
15: “Deep-Sea Corals”, Written by Greater Farallones National Marine Sanctuary. Published on an unknown date by the National Oceanic and Atmospheric Administration
16: “California's Rock Reefs”, Written by OC Habitats. Published on February 15, 2021, by OC Habitats
17: “Exploring the Cold-Water Corals of the California Coast”, Written by Robert Eagle. Published on Unknown Date 2025 by UCLA Institute of Environment and Sustainability
18: “Exploring Corals of the Deep”, Written by Sheraz Sadiq. Published on March 9, 2016, by KQED National Public Radio News
19: “Deep-Sea Coral and Sponge Community Observatory at Sur Ridge”, Written by Monterey Bay National Marine Sanctuary. Published on Unknown Date by National Oceanic and Atmospheric Administration
20: “Using Fecal Transplants to Treat Dolphins with Gastrointestinal Disease”, Written by Sho Kodera. Published on April 4, 2024, by Scripps Institution of Oceanography https://scripps.ucsd.edu/news/using-fecal-transplants-treat-dolphins-gastrointestinal-disease
21: “Evaluation of the Safety and Efficacy of Fecal Microbiota Transplantations in Bottlenose Dolphins (Tursiops Truncatus) Using Metagenomic Sequencing”, Written by Barbara K Linnehan, Sho M Kodera, Sarah M Allard, Erin C Brodie, Celeste Allaband, Rob Knight, Holly L Lutz, Maureen C Carroll, Jennifer M Meegan, Eric D Jensen, Jack A Gilbert. Published on February 1, 2024, by National Library of Medicine, Oxford University Press
22: “Researchers Carry Out First Peer-Reviewed Study of Fecal Microbiota Transplants in Dolphins”, Written by Linda Stewart. Published on Unknown Date March 2024, Updated May 2, 2024 by National Marine Mammal Foundation
23: “Marine Mammal Program”, Written by Unknown. Published on Unknown Date by Naval Information Warfare Center
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As Triumph the Insult Comic Dog might say, "This is a great article ... FOR ME TO POOP ON!" Seriously, though. This was an informative and entertaining read. I learn something from this writer every time I visit this site. Well done!