Genetic connectivity

Pocillopora coral samples from this campaign allowed to confirm that the specific diversity within this genus is under-estimated. Connectivity patterns are specific to the studied species: species present on the outer reef slope present a high degree of connectivity among their populations (Figure 1), contrary to those inhabiting shallow waters and lagoons (Pocillopora damicornis and P. acuta).

Concerning the hydrozoan Macrorhynchia phoenicea, the genetic connectivity among its populations is extremely weak, each island presenting its own genetically isolated population.

Figure 1. Distribution of the different species hypotheses from the Pocillopora corals present on the outer reef slopes, from New Caledonia and Chesterfield/Bampton/Bellona islands, with the main marine currents of the zone represented.

Biodiversity of scleractinians and macroalgae

New species of scleractinians and macroalgae have been described, showing that the biodiversity of this region is still under-explored.

As for the macroalgae, the sampling during this campaign allowed to significantly enrich the knowledge of the marine flora poorly studied in this part of the Coral Sea Marine Park, especially for the green algae Bryopsidales and in particular for the families Udoteaceae and Rhipiliaceae and the genus Avrainvillea (Dichotomosiphonaceae). Thanks to an exhaustive study combining molecular tools and morphology, several taxa have been confirmed for the Udoteaceae and Rhipiliaceae and several genera described (Glaukea, Ventallia, Udoteopsis, Kraftalia, Rhipiliospina), for which several species were described or resurrected. Some of these species are endemic of the Chesterfield Islands (Figure 2).

Figure 2. Phylogenetic tree (maximum likelihood) of the macroalgae from the new genus Rhipiliospina for which the species found in Chesterfield is endemic.