Coral in Nova Scotia. No Way!
You might think coral only exists in the tropics, but deep off the coast of Nova Scotia, coral exists in the cold waters of the Atlantic Ocean!
Lophelia pertusa is one of these cold-water corals, found at depths below 150 meters on the seafloor. One of the only known locations of this species in Atlantic Canadian waters is The Lophelia Coral Conservation Area, located at the edge of the Scotian Shelf. This reef plays an important role as a spawning and breeding ground for a variety of marine animals, providing refuge in the deep sea.
Lophelia pertusa is a stony coral with a branching shape that can be bright orange, white, or pink. These corals can live to be hundreds even thousands of years old, growing as tall as 35 meters (115 feet)!
Make it stand out
Orange and pink fragment of Lophelia pertusa on a Department of Fisheries research vessel. Photo credit: DFO Canada
(https://www.dfo-mpo.gc.ca/oceans/oecm-amcepz/refuges/lophelia-eng.html)
A single coral is known as a polyp. Lophelia pertusa polyps live together in colonies that can be made up of hundreds of thousands of individuals. Beneath the delicate layer of polyp tissue lies a stony structure, formed as these corals produce calcium carbonate skeletons - much like bones in the human body.
As Lophelia pertusa grows, new tissue grows over old skeletons, gradually forming reef rock over many years. The nooks and crannies of the coral reef create a complex habitat, serving as a bustling home for fish, squid, crabs and other invertebrates - essentially an underwater hotel! This diverse ecosystem plays a crucial role in maintaining the health of marine life, creating a rich environment for a wide range of species.
Lophelia pertusa reef with a king crab and sea urchin nestled in the coral.
Photo Credit: Oceana (https://oceana.ca/en/marine-life/lophelia-coral/)
Corals are omnivores meaning they consume both plants and animals. They are suspension feeders, collecting floating food particles from the water column. Lophelia pertusa polyps have 16 protruding tentacles surrounding their mouth at the end of each branch. When food drifts past, the tentacles inject venom into the prey, stunning them and making them easy to consume. Unlike shallow-water tropical corals, Lophelia pertusa do not host zooxanthellae - the symbiotic phytoplankton that live within the cells of many reef-building corals. This is because there is not enough light in the deep sea to support photosynthesis.
Close-up picture of white Lophelia pertusa polyps extending their tentacles.
Photo Credit: Solvin Zankl, 2012 (https://www.researchgate.net/figure/Close-up-picture-of-white-Lophelia-pertusa-polyps-extending-their-tentacles_fig1_344487243).
Lophelia pertusa faces significant threats from fishing activities, particularly bottom trawling, which can destroy entire reefs while collecting groundfish and shellfish. Preserving these reefs is crucial for maintaining biodiversity and supporting the species that rely on them. Expanding no-trawling zones, guided by further research could benefit both the ecosystem and nearby fisheries by enhancing species diversity. Collaborating with fisheries would also improve data collection, further aiding in the protection of Lophelia pertusa. Beyond direct human impacts, climate change poses a serious threat to coral. Rising sea temperatures lead to ocean acidification, which impacts coral growth and reproduction. This highlights the need for continued conservation efforts. In response to past damage, The Lophelia Conservation Area has banned bottom trawling to protect these vital ecosystems. Biodiversity resurgence has been observed in these types of marine protected areas, making them a great conservation tool, sparking hope for the future of our ocean!
Author Biography:
Emily is a recent graduate from Dalhousie University with a bachelor’s in marine biology. She is a lifelong sailor from Halifax who now sails internationally. However, she has made it her mission to continue protecting and investigating her home waters of Nova Scotia.