Structure and Development of Hawaiian Deep-Water Coral Communities on Mauna Loa Lava Flows

Submarine lava flows on the leeward flank of the island of Hawai‘i, USA, were examined by submersible and remotely operated vehicles to understand the structure and development of deep-water coral communities. Three sites were selected where historically documented lava flows crossed older prehistoric flows, providing three pairs of lava substrates of different ages (61/400 yr, 134/2000 yr, 143/2330 yr) to compare and contrast with a nearby older coral community (15000 yr) growing on fossil carbonate. The number of coral taxa, abundance, and colony size increased with substrate age on the three historical lava flows and fossil carbonate site, but not on the prehistoric flows. The faster-growing Coralliidae were the dominant taxa forming patches on the peaks of ridged terrain, while the slower-growing Antipatharia and Isididae were less abundant except at the fossil site where the community was dominated by the slowest-growing corals, including Kulamanamana haumeaae. A multivariate analysis of similarity of coral communities on lava flows found site, rather than substrate age, to be a better explanation for why paired flows were ecologically the same despite considerable age differences. The data suggest that hot, turbid, mineral-rich water from the more recent historical lava event re-initialized the community succession of the adjacent prehistoric lava substrate. Coral mortality would be greatest close to the edge of the historical flow with the expectation that survivorship would increase with distance from the impact. The survey transects were too short to detect a significant increase in the total coral community, but an increase was evident for the Coralliidae.

Putts MR, Parrish FA, Trusdell FA, Kahng SE. 2019. Structure and development of Hawaiian deep-water coral communities on Mauna Loa lava flows. Published in Marine Ecology Progress Series. https://doi.org/10.3354/meps13106.