Millions of years ago, the Earth’s plates were very, very slowly pushing the Great Meteor hot spot on a southeastern path from Hudson Bay toward the Atlantic Ocean. Along the way, hot plumes of magma welled up under the Earth’s crust, forming chains of volcanoes marking the hot spot’s track. Between 124 and 100 million years ago, New Hampshire pushed over the hot spot, and the White Mountains were formed. Then, about 100 to 83 million years ago, the New England Seamount Chain was formed in the Atlantic Ocean. Bear Seamount was the first underwater volcano to arise in the chain.
Looking northeast towards Bear Seamount with Physalia Seamount in the background. Image via NOAA Okeanos Explorer Program.
A Bear of a Seamount
The New England Seamount Chain volcanoes have not been active since their formation. They exist as huge underwater mountains that host a spectacular variety of marine organisms. The chain encompasses more than 30 major volcanic peaks and stretches nearly to Bermuda!
Bear Seamount is the northwestern most seamount in the chain, lying just south of Georges Bank. It rises up from the depths of the continental floor between 6,500 to 10,000 feet deep and summits to a flat peak 3,600 feet below the ocean surface. Its exterior is a combination of thick sediment, volcanic outcroppings, and rocks deposited by glaciers thousands of years ago.
Two major ocean currents run perpendicular to Bear Seamount: the Gulf Stream and the Deep Western Boundary currents. These currents dramatically influence water temperature, creating an environment that is unique to the Northwestern Atlantic.
Creatures from the Deep
For a long time, scientists did not know which species called Bear Seamount home, but recent research cruises have unveiled an underwater world full of unique marine life – Bear Seamount is truly a biodiversity hotspot.
The Gulf Stream and Deep Western Boundary currents produce favorable environmental conditions for an assortment of creatures that are not typically associated with the nearby continental slope. This includes organisms such as the Eastern Atlantic spiderfish, the cutthroat eel, and the Arctic rockfish. We had no idea that many of these organisms existed in the Western Atlantic before they were discovered at Bear!
A cutthroat eel consumes a squid for dinner. Image via NOAA Okeanos Explorer Program.
A wide array of corals, sponges, and mollusks populate the seamount. Many of these species support astounding mobile invertebrate populations, including squid, tubeworms, octopods, and crustaceans. The combination of coral habitat and ample prey at Bear Seamount provide ideal conditions for deep sea fish populations, such as the lancetfish.
Check out some of the crazy creatures found on the NOAA Pisces 2012 research cruise to Bear seamount – lancetfish, dragonfish, catsharks, sea spiders, blind lobsters, and more!
The undereye area of the threadfin dragonfish (Echiostoma barbatum) is bioluminescent, meaning it emits light. Image via NOAA Okeanos Explorer Program, Bioluminescence and Vision on the Deep Seafloor 2015 expedition.
Bear Seamount is an ecologically critical undersea region. Its unique conditions foster a diverse community of species not typically found in the region, and its coral populations provide shelter and spawning grounds for a wide array of organisms. How could we possibly threaten this rich ecosystem?
The danger lies in the potential for fishery development. Since 1997, some fishermen have had their eye on the region; many are convinced the region has potential for orange roughy and roundnose grenadier fisheries. But this could spell disaster for the delicate deepwater system.
Sessile organisms, such as corals and sponges, are extremely vulnerable to destruction from trawlers; they are frequently either removed from the ecosystem altogether or severely damaged from trawling gear sweeps. Many coral species on Bear Seamount, such as Lophelia pertusa, are critical components of the reef, but are slow-growing and therefore take thousands of years to recover from disturbance. Slow-maturing fish species found on Bear Seamount, such as the roundnose grenadier, are susceptible to overfishing because of the length of time it takes for stocks to replenish.
Lophelia Pertusa. Courtesy of NOAA.
Potential offshore oil and gas development could also severely damage this delicate ecosystem. Even exploratory operations, such as seismic testing, put marine mammals and fish at risk. Ultimately, at a time when climate change and ocean acidification are stressing deep sea coral communities, it is important that we do all we can to prevent further destruction.
Bear Seamount and the whole New England Seamount Chain are deep sea treasures that need our protection.