Among the least observed ecosystems on the planet are seamounts. Seamounts are active or extinct volcanoes deep below the sea’s surface. While the exact number is unknown, scientists estimate there are anywhere from tens of thousands to 100,000 seamounts worldwide. These special geological features of the ocean basin are important because of their effect on ocean currents and ecosystem composition.
Towering as high as 4,000 meters (more than 10,000 feet) above the seafloor, deep waters are forced upwards along the slopes of seamounts, a phenomenon known as upwelling, carrying nutrients and plankton from the depths to support a rich ecosystem with high densities of corals, sponges and fishes. As currents sweep over the seamount peaks they also disrupt sedimentation, providing refuge points to species like coral that rely on hard substrates to anchor themselves. According to the Woods Hole Oceanographic Institute, these deep-sea corals serve as hosts to more than 1,300 other species of animals, over 80 of which are commercially fished.
In the vast stretches of the ocean, seamounts become underwater ‘islands’ of life and biological diversity with potentially high rates of endemism – species that are unique to a specific ecosystem and location. The nature of isolation for these biological hotspots is key to understanding their sensitivity to human activities such as fishing and the emerging industry of deep-sea mining. Yet, despite their ecological significance, much is still unknown about seamounts. Scientists are conducting research to understand both how these critical marine systems work, and why including seamounts in conservation measures could be critically important for both ecological and economic security.
Threats to Seamounts
The unique qualities that make seamounts so ecologically productive also make them incredibly vulnerable to human exploitation. The rich concentrations of plankton and the hard substrates that are exposed as the deep currents sweep over the peaks offer refuge for species across the food chain, all interconnected and in balance. Among the corals, fish can spawn and the juvenile fish, called ‘fry’, find shelter and food to grow, attracting hungry predators seeking a meal. With nearshore fisheries facing depletion, seamounts represent an opportunity to protect fish populations. Yet the fishing industry shows no signs of slowing and many seamounts already display scars from trawling and abandoned fishing gear.
Another threat to seamounts is deep-sea mining. Their association with volcanic activity provide seamounts with rich mineral deposits in the form of a thin crust across their surface. The same dynamics that expose these mineral crusts as hard substrates for corals to attach to also make it accessible for mining, and not without a cost to the ecosystem. Woods Hole Oceanographic Institute states that 27 countries are already making plans and developing technology to mine these mineral deposits. With still little understood about the nature, resilience and interconnectedness of these ecosystems, seamounts are at risk of rapid exploitation and destruction, a fate history has demonstrated with the deforestation of old-growth forests and tropical rainforests.
Tens of thousands of seamounts hide deep beneath the ocean’s surface harboring biological hotspots that could be threatened by deep-sea mining. Source: Wikimedia Commons
Along with these direct threats, seamounts face uncertainty with the impacts of broader threats, including ocean acidification and warming sea temperatures. In 2016, the Obama Administration designated the first marine reserve in the Atlantic Ocean, named the Northeast Canyons and Seamounts Marine National Monument, with the intent to permanently protect four seamounts and three underwater canyons off the Northeastern United States. This measure was in response to warnings from NOAA of the drastic increase in sea temperatures predicted for the northeast coast (projected to be climbing three times faster than the global average), and urgings from ocean conservation organizations and experts, included world renowned oceanographer and Explorer-in-Residence for the National Geographic Society Dr. Sylvia Earle, and marine conservation photographer Brian Skerry. By protecting these biological hotspots, experts and policy makers are taking steps to increase resilience in fish populations by protecting key sanctuaries, including the four seamounts. While this marks a significant milestone for seamount conservation, the designation of this national marine monument faces threats as local fishing communities challenge the restrictions based on alleged impacts to the local fisheries economy.
In the race to protect seamounts from exploitation, scientists are working to better understand the ecology and structure of seamounts. In September 2016, Conservation International, in collaboration with the University of Hawai’i, conducted a Seamount Rapid Assessment of three seamounts off the coast of the ‘Big Island’ of Hawai’i. Lead by Conservation International Chief Ocean Scientist Dr. Greg Stone, the Seamount Rapid Assessment was designed to survey a spectrum of seamounts to begin to paint a picture of the physical and biological composition of these diverse habitats. Targeted in the expedition were the Cook and McCall seamounts, two extinct volcanoes from the little-studied Geologist Seamounts (a ring of ancient volcanoes roughly 80-million years old), and a still-active submerged volcano known as Lo’ihi, the youngest of the Emperor Chain, better known as the Hawaiian Islands.
According to Dr. Stone, during expeditions to unobserved ecosystems like the Geologist Seamounts, there is a good chance for discovering new species. Sighting a unique purple sea fan coral, Dr. Sonia Rowley, a research fellow at University of Hawai’i – Mānoa and specialist in gorgonian corals, was excited to take her sample, dubbed “Purple Haze,” back to the lab, enthusiastic that it might be a species new to science. Findings like these give clues to the true nature of endemism within seamount ecosystems and highlight the need for more studies to document the biodiversity seamounts hold and the vulnerability of seamounts to the many threats these unique ecosystems face.
A key objective of the Seamount Rapid Assessment expedition was to deepen scientific understanding of these vulnerable ecosystems to better position seamounts in global conservation measures. The mission inspired support from Glenn Bucksbaum, ocean conservationist and president of the Baum Foundation, who recognized the importance of missions like this and their role in understanding what’s at stake for these key ecosystems and the biodiversity they harbor. By supporting marine researchers, the Baum Foundation seeks to raise awareness of important ocean conservation issues and to work towards greater public understanding and sound conservation management plans.
In the case of the Northeast Canyons and Seamounts Marine National Monument, research and advocacy led to informed protection measures. However, if scientists and stakeholders don’t stay ahead of economic pressures for resources, we may lose the chance to protect these vulnerable ecosystems before they are gone. It will take an international community to protect seamounts and the rich biodiversity that they support.
Tessa Diem’s field and project work in environmental science encompasses biodiversity and climate change. Her writing explores the connections between society and the environment and how we can utilize impactful solutions in the challenges we face for marine and terrestrial ecosystems. Tessa is interested in how we design and engage with our environment to create a greater sense of place and foster a communal responsibility for our planet.
Glenn Bucksbaum is a citizen scientist supporting marine science exploration. He contributes his drone photography to conservation and writes about the role of research and science in conservation. His support spans the globe where his contributions and support for marine science research, marine protected area designations and economic alternatives to destructive fishing practices provide input and solutions for implementation.
Michael Garlandis a regular contributor to The Baum Foundation, using his professional expertise in photography to capture the stories and impact of each unique Baum program. Throughout his career, Michael has been a contributor to Time, Newsweek, and Esquire. Michael contributes his work to support causes he believes in to tell meaningful stories.