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The extent to which scleractinian coral inhabited southern Australia during the warm intervals of the Quaternary is poorly understood because identifiable corals from interglacial sedimentary recor...

In this study, the complete mitogenome sequence of the Goniopora lobata has been sequenced using next-generation sequence method. The overall of G. lobata mitogenome is 25.72% for A, 13.59% for C, 23.42% for G, and 37.27% for T, as well as 37.01% for low GC. The assembled mitogenome, consisting of 18770 bp, has 13 unique protein-coding genes (PCGs), three transfer RNA genes, and two ribosomal RNA genes. The complete mitogenome of G. lobata provides essential and important DNA molecular data for further phylogenetic and evolutionary analysis of stony coral phylogeny.

A simple, non-destructive and objective method is developed and evaluated to quantify bleaching or colour change in coral in terms of its percent whiteness. Digital photos of coral colony were taken with a photoquadrat marked with black and white bands around a metal frame to serve as colour references. Photos taken were then converted to a black and white grey-scale and intensities of the coral colour were determined with reference to this grey-scale using computer image analytical technique. A completely bleached coral gave an estimated percent whiteness that is close to 100%, an estimate that agrees well with the visual image of a bleached coral. The percent whiteness estimates were found not to be significantly affected by different levels of irradiance and turbidites under simulated conditions. Colour change in seven common Hong Kong coral species were further evaluated in situ and shown to exhibit an increasing trend of percent whiteness from January (winter) to April 2012 (spring), reflecting an increasing degree of bleaching. Using Goniopora lobata as an experimental species, estimated percent whiteness was shown to be negatively correlated with its zooxanthellae density and chlorophyll a concentration. This suggests that this method could allow repeated monitoring of individual coral colony over time to detect subtle variations in its colour as a general assessment of its health. Furthermore, reference percent whiteness of different coral species can be standardized for comparison of colour change over time to identify the critical level of percent whiteness that is associated with bleaching. Thus, this method should prove to be an easy and objective tool for rapid field assessment of coral health.

SUMMARY Tentacle expansion and contraction were investigated in four zooxanthellate coral species and one azooxanthellate coral (Cladopsammia gracilis). Favia favus, Plerogyra sinuosa and Cladopsammia gracilisexpand their tentacles at night, while tentacles in Goniopora lobataand Stylophora pistillata are expanded continuously. Light at wavelengths in the range 400-520 nm was most effective in eliciting full tentacle contraction in F. favus and in P. sinuosa. Higher light intensities in the range 660-700 nm also caused tentacle contractions in F. favus. Tentacles in C. gracilis did not respond to light. Zooxanthellar densities in tentacles were significantly higher in G. lobata, which has continuously expanded tentacles, than in F. favus and P. sinousa, where tentacles are expanded at night. Photosynthetic efficiency in F. favus and P. sinuosa was lower in specimens with contracted tentacles. However, in the dark, no differences were found in the maximum quantum yield of photochemistry in PSII(Fv/Fm) of the expanded versus the contracted tentacles of any of the four species. This work suggests that species whose tentacles remain continuously expanded have either dense algal populations in their tentacles,as in G. lobata, or minute tentacles, like S. pistillata. Dense algal populations in tentacles allow harvesting of light while small tentacles do not scatter light or shade zooxanthellae in the underlying body of the polyp.

1. Electrical or mechanical stimulation of Goniopora lobata produces coordinated retraction of polyps in the colony. With repetitive stimulation, the response spreads in linear, radial increments which become successively smaller with each stimulus. 2. Electrical activity recorded from these colonies is interpreted as originating in a conduction system responsible for effecting the colonial retraction response. The electrical activity spreads incrementally through the colony in a similar manner to the behavioural response. 3. Various hypotheses have been proposed to account for such a spread of electrical acitvity. Of these, only interneural facilitation is of appreciable importance to Goniopora. 4. Temporary termination of a pathway, by the passage of an impulse through it, was found and interpreted as being an additional and important property of the colonial conduction system.