artsprosjektet_47-14_organophilic_annelids

Study Extent

15 sites visited one time.

Sampling

Sampling at most of the sites has been based on gab samples using a standard van Veen grab. The grab has been lowered directly underneath the aquaculture site as well as at some distance from the site forming a transect from heavily impacted to less impacted sediment. From sites where the substrate are dominated by rocks the grab cant be used. Instead some kind of remotely operated vehicle must be deployed with attached scoop nets or similar collecting devices. The grab samples has been sieved on a 1 mm mesh sieve and preserved in the filed using 96% EtOH. Once back in the lab the EtOH was changed. The samples has been stored in a fridge kept at +4°C. We have also examined one sample from an experimentally deployed "natural" organic fall consisting of wood and vertebrate bone (cow). Wood and bone has been hypothesised to be the natural habitats for many of the taxa found also at anthropogenic organic rich habitats. While the dominant taxa at wood and bone habitats are organisms able to bore in the hard substrates (Xylophagid bivalves and frenulate annelids belonging to the genus Osedax), the matrix created by the boring organisms constitute a habitat for many other species studied in this project. The organic falls will typically also provide a substrate for large bodied filamentous bacteria on which many species of annelids live. After lifting the entier experiment to a boat (it was attached to the shore using a submerged rope) the samples was kept under water and sorted in the lab on shore.

Method steps

1. -

Norway