Deep-water coral community off the Big Island. Photo courtesy of UH/HURL

New research reveals growth rates of deep-sea coral communities for the first time, and the pattern of colonization by various species, according to a news release by the University of Hawai‘i.

The study was a collaboration between researchers at UH Mānoa School of Ocean and Earth Science and TechnologyHawaiʻi Pacific University and the National Oceanic and Atmospheric Administration.

The scientific team used the UH Mānoa Hawaiʻi Undersea Research Laboratory’s submersible and remotely-operated vehicles to examine coral communities on submarine lava flows of various ages on the leeward flank of Hawaiʻi Island. Utilizing the fact that the age of the lava flows — between 61 and 15,000 years — is the oldest possible age of the coral community growing there, they observed the deep-water coral community in Hawaiʻi appears to undergo a pattern of ecological succession over time scales of centuries to millennia.

The study (PDF) reported Coralliidae or pink coral, were the pioneering taxa, the first to colonize after lava flows were deposited. With enough time, the deep-water coral community showed a shift toward supporting a more diverse array of tall, slower growing taxa: Isididae, bamboo coral, and Antipatharia, black coral. The last to colonize was Kulamanamana haumeaae, gold coral, which grows over mature bamboo corals, and is the slowest growing taxa within the community.

Pink coral, left, and gold coral, right, near Hawaiʻi. Photo courtesy of UH/NOAA Office of Ocean Exploration and Research

“This study was the first to estimate the rate of growth of a deep-sea corals on a community scale,” said Meagan Putts, lead author of the study and research associate at SOEST’s Joint Institute for Marine and Atmospheric Research. “This could help inform the management of the precious coral fishery in Hawaiʻi. Furthermore, Hawaiʻi is probably the only place in the world where such a study could have been performed due to its continuous and well known volcanology.”

“Prior to beginning this work, it was unclear if a pattern of colonization existed for deep-sea coral communities and in what time frame colonization would occur,” said Putts. “When put into context with what we do know about the life history of Hawaiian deep-water corals, the results of this work make sense.”

This study has important conservation and sustainability implications regarding these ecosystems that had never before been ecologically quantified. This research also provides insights about recovery of deep sea ecosystems that may be disturbed by activities such as fishing and mining.

“Further,” said Putts, “as the Island of Hawaiʻi continues to have periodic eruptions producing very recent deep-water lava flows, the last in May 2018, there are opportunities to study initial settlement patterns and appraise the impact hot, turbid, mineral-rich water from new flows has on coral communities.”