Biopapua / Wide Bay
17 October 2010
October 17, 2010
This is the penultimate day of the cruise, and we still hope to find a good area to sample sunken wood, such as those we had found along the island of New Guinea.
The dredge is first dragged through the underwater canyon that extends from the river bed in Wide Bay. We get mostly pebbles, but also some leaf debris.
The second operation, using the trawl, follows the canyon’s main axis downhill. Once retrieved, the content of the trawl floods the deck with all sorts of debris, including entire tree trunks. We keep sampling, deeper than a thousand meters.
Among the contents of that last deep trawl, we are pleased to find a big tree branch colonized by clusters of small undescribed marine fungi.
These beautiful specimens will usefully complement the collections that are destined for our colleague Joëlle Dupont (MNHN). Joëlle has participated on several "sunken wood" cruises, and has described a new species of deep-sea fungi that was attributed to its own new genus.
She chose to name this new species Alisea longicolla, in tribute to the work of the crew of the R/V Alis, thanks to whom we accumulate such fine collections.
Many organisms sampled from sunken woods are yet to be studied, both in terms of their diversity and the nature of their dependence on this type of substrate.
For instance, these sea stars are strictly associated with sunken wood, but what is the nature of this dependence? Do they feed directly on the wood? Do they graze on the biofilm covering the trunk? Or do they simply use this substrate as a shelter?
