Sunken wood from the Vanuatu Islands: identification of wood substrates and preliminary description of associated fauna

Abstract

Two trawl samples of natural sunken wood collected near Vanuatu were identified based on histological studies. Detailed descriptions were made and microphotographs of the cell types were taken, using the three classical sections (cross, tangential and radial). The botanical characters were compared first to the native flora of Vanuatu, then also to the introduced species. The possibility of transportation by ocean currents with a mainly southern and eastern direction is discussed. The first sample lacks apparent colonization marks. Its main histologic character is the presence of ‘paedomorphic type I rays’ which relates it to the shrubby genera Fitchia (Asteraceae) and Fuchsia (Onagraceae): both are known in Polynesia but they seem not to be recorded from Vanuatu. The second wood sample is densely colonized by molluscs and other fauna. It comes from a tree close to the Fabaceae‐Mimosoideae, possibly belonging to the genera Leucaena or Serianthes, both known from Vanuatu. Our work shows for the first time that, even after prolonged submergence in water at substantial depth (>500 m), the wood structure may be well preserved. Therefore, the botanical identification and the determination of the origin of the sunken wood were possible. The two selected samples show completely different colonization patterns, which could be related to differences in chemical composition or to time elapsed since sinking.

Ecosystem function and services provided by the deep sea

“…In addition, over these time periods a diversity of successional stages occurs from scavenger, to specialist fauna and finally with the bones acting as hard substrate for filter feeders. Wood and leaf deposits create an additional type of similar habitat on shelf, fjord, slope, and abyssal habitats near wooded continental margins (Wolff, 1979;Pailleret et al, 2007). These terrigenous deposits create both an additional type of carbon sequestration, while providing high levels of primary and secondary production to the deep-sea floor (Turner, 1977;Bernardino et al, 2010) and its associated supporting, regulating, and provisioning services.…”

Wood-based diet and gut microflora of a galatheid crab associated with Pacific deep-sea wood falls

“…The group has received a careful attention since the 1980s in the description of the animal communities (e.g. Marshall 1985Marshall , 1988Kiel and Goedert 2006a, b;Pailleret et al 2006), as well as in the study of the impressive taxonomic diversity of mussels (Samadi et al 2007;Lorion et al 2009). Moreover, the phylogenetic relationships among wood-, bone-, vent-, and seep-associated mussels led to propose the "stepping stones" hypothesis for the colonization of the deep-sea reducing environments (see Smith et al 1989;Distel et al 2000).…”

<i>Spinaxinus</i> (Bivalvia: Thyasiroidea) from sulfide biogenerators in the Gulf of Mexico and hydrothermal vents in the Fiji Back Arc: chemosymbiosis and taxonomy

“…The thyasirids were not unique to the traps but were known from the surrounding sediments (Gaudron et al 2010). Small thyasirids, associated with woodfalls, are also reported by Bernardino et al (2010) but not by Pailleret et al (2007) or by Bienhold et al (2013). Deep-sea settings influenced by macrovegetation input have been studied, including the Puerto Rico and Cayman trenches in the Caribbean, but hereto thyasirids have not been reported (Wolff 1979).…”