Preface The expedition ARK XIX/3 with the German icebreaking RV ...

- Molecular phylogeny and phylogeography of selected deep sea taxa
In parallel to a morphological approach, a molecular study is carried out in order to
obtain a robust molecular phylogeny of selected amphipod taxa (with special reference
to lysianassoids), on the basis of different nuclear and mitochondrial gene fragments.
Such a phylogeny will be subsequently used as a tool for studying different issues
related to biogeography, origin, colonisation and evolutionary biology of benthic taxa
from the two polar regions.
Moreover, due to the temporal dimension included in models commonly used for
phylogenetic reconstructions, data about tempo and mode of evolution in lysianassoids
taxa are expected. They should enable us to contribute to reconstruct the evolutionary
scenario of this group, to study radiations within the group and to identify possible
species flocks, cryptic species, as well as convergent adaptive radiations (in particular
adaptations related to trophic niches).
- Trophodiversity and trophodynamics
In the framework of a general approach to understand the ecofunctional role of the
amphipod taxocoenoses in the Polar and deep-sea benthic ecosystems, the project
aims at contributing to characterize the trophodiversity and the trophodynamic role of
selected Arctic deep sea amphipods and at comparing it in different benthic communities
on bipolar and bathymetric scales.
The trophic approach will rely on the use of stable isotope ratios (carbon, nitrogen) as
amphipod diet tracers combined with digestive tract analyses to delineate the trophic
relationships involving amphipods in the Arctic deep sea food webs. The results will be
compared to a similar trophic study undertaken in the Antarctic.
Work at sea
Baited trap sets were deployed three times, twice from the ROV and once from a Lander
(see Tab. C13-1). In addition, large box corers samples provided additional amphipod
and tanaid material. Whenever possible, the freshly collected material was identified to
the species level. Parts of the living animals from trap samples were maintained in
aquariums for behaviour and feeding biology observations. DNA extractions were
performed from selected specimens of all possible sampled species.
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