Biopapua / Astrolabe Bay
06 October 2010
Mardi 5 et Mercredi 6 octobre
The last leg of Biopapua begins in Astrolabe Bay, a name which evokes the passage in the early 19th century of the French explorer Jules Dumont d'Urville and his boat, Astrolabe. Here, as everywhere around New Guinea, large rivers flow into the bay. The results of the first trawl meet our expectations, as we get large amounts of mud mixed with plant debris.
We take multiple samples to get an overview of the diversity of these benthic assemblages, which varies from one place to another, and from one depth to another. One of our samples is dominated by small sessile crustaceans (cirripedes or barnacles).
We had already found these animals sporadically, attached to various plant substrates, but had never witnessed such a profusion! Moreover, sampling has shown that these animals can attach themselves to all kinds of substrates: seeds, seaweed debris from shallower areas, stones, twigs but also plastic waste.
A little later, in the same bay, the multibeam sonar reveals the presence of a canyon in the extension of a river bed.
We sample at the bottom of this canyon and harvest large quantities of leaf and branch debris. Unfortunately, this substrate is barely populated, and we really feel as we are looking for needles in a haystack.
The only interesting organisms we find are small crustaceans, amphipods, isopods and copepods that are small but very diverse. We keep these treasured unfamiliar animals for Laure Corbari, who recently undertook their study.