Settlement, colonization, and succession patterns of gold coral Kulamanamana haumeaae in Hawaiian deep coral assemblages

Abstract

The Hawaiian gold coral is a parasitic zoantharian that colonizes other deep corals and secretes a protein skeleton that over millennia can grow and more than double the original mean size of the host colony. Surveys at 6 known coral beds in the Hawaiian Archipelago found mature gold coral to be a common taxon and dominant at the geologically older sites. Fewer than 5% of the gold coral colonies seen were in the process of subsuming their host, described here as the 'midas' phase. Bamboo coral (Acanella, Keratoisis) comprised 85% of the midas colonies, with two-thirds found at the youngest site, where the mean height of bamboo coral was significantly greater than at other sites. Marked midas colonies revisited after 5 yr showed the gold coral tissue spreading across the host at an estimated rate of 2.2 ± 0.69 cm yr −1 (mean ± SD). Cross sections of mature gold coral colonies show the host averages just 9.8 cm of the stem's core, indicating that much of the host skeleton is lost when subsumed by gold coral tissue. The absence of midas colonies in a bamboo coral assemblage found growing on a 76 yr old wreck close (~1 km) to a mature gold coral patch suggests that gold coral recruitment is infrequent. This time lag between the growth of the host and the arrival of the gold coral successor is essential because otherwise the speed of the midas phase would subsume the host population faster than it could replenish.

Structure and development of Hawaiian deep-water coral communities on Mauna Loa lava flows

“…None of the lava flow coral communities resembled the high-diversity community at Keāhole (15 000 yr). The absence of mature K. haumeaae colonies despite the availability of Isididae substrate on the lava flows confirms that this species is very slow (>100 yr) to recruit in considerable numbers (Parrish 2015). Although the data in this study are limited, the diversity trend with age of the communities studied with the highest diversity at Keāhole (15 000 yr) implies that community succession takes several millennia to run its course (per the intermediate disturbance hypothesis ;Connell 1978, Parrish 2015.…”

“…The absence of mature K. haumeaae colonies despite the availability of Isididae substrate on the lava flows confirms that this species is very slow (>100 yr) to recruit in considerable numbers (Parrish 2015). Although the data in this study are limited, the diversity trend with age of the communities studied with the highest diversity at Keāhole (15 000 yr) implies that community succession takes several millennia to run its course (per the intermediate disturbance hypothesis ;Connell 1978, Parrish 2015. Alternatively, the coral community structure could be inherently different on carbonate substrate (vs. basalt), or the intermediate disturbance hypothesis may not apply to deep-water coral communities (Fox 2013, Sheil & Burslem 2013.…”

“…In addition to colony size, the parasitic life history of K. haumeaae was indicative of community age. The colonies observed on the oldest of the historical lava flows (143 yr) were in the 'midas' stage of development, the initial colonization phase when the zooanthid rapidly spreads and subsumes the bamboo host (Parrish 2015). The colony collected on the adjacent prehistoric flow (2330 yr) appeared to be older, as the host skeleton was entirely encased and was in the earliest stages of creating a proteinaceous skeletal matrix needed to grow larger.…”

“…Bamboo and other coral colonies on the old flow may have been killed by the more recent adjacent historical flow, but their skeletons could have persisted and still served as a host for gold coral recruitment. Gold coral have been observed growing on dead or partially dead bamboo colonies (Parrish 2015), suggesting that gold coral could have colonized the prehistoric flow sooner given the presence of suitable host substrate, whereas on the historical flow, suitable bamboo host substrate would not become available for nearly 100 yr after the lava cooled. However, more exten-sive surveys are required to characterize the extent of spatial and temporal impacts of this type of disturbance on the adjacent older coral community.…”

New Frontiers in Ocean Exploration: The E/V Nautilus and NOAA Ship Okeanos Explorer 2015 Field Season

“…The dive transect crossed both older substrate and new substrate, thereby providing information on resettlement, recovery, and early phases of deep-sea coral community development. The concept of succession seems to apply to gold coral communities because they must grow over other existing corals to become established (Parrish, 2015). Mature gold coral communities, where many of the other species, primarily bamboo corals, have been overgrown, could be quite old (Roark et al, 2006).…”