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The distribution of Lophogastrida

The unique material and data collected by MAR-ECO on the mid-Atlantic Ridge are being analysed  by numerous post-graduate students. In "Student of the month" Pål Øyvind Aas from the University of Bergen (Norway) is presenting his work on the distribution of Lophogastrida (Crustacea) along the Mid-Atlantic Ridge.

paal oeyvind aas

Student of the month
Pål Øyvind Aas
MS -student at department of Biology at the University of Bergen, Norway

Topic
The distribution of Lophogastrida (Crustacea) along the Mid-Atlantic Ridge

Completed
On 10 February 2006, Pål Oyvind Aas successfully defended his thesis.


Photo: Paal Oeyvind Aas
A female of the species Gnathophausia zoea with a fully developed brood-chamber (arrow). Photo: Pål Øyvind Aas

Lophogastrida is an order of deep sea Crustaceans inhabiting the mid-Atlantic Ridge. These animals are most commonly found at depths below 1500 meters. They were captured in large numbers on the MAR-ECO expedition in the summer 2004. These animals are related to and quite similar in appearance to shrimp and krill. However, unlike shrimp and krill, the females of this group have a brood-chamber on their ‘belly’ were the eggs are kept, and they are generally known as more primitive in having many characters more similar with ‘older’ fossilized species of crustaceans.

Looking at the differences in size, shape and number of spines that cover the bodies of these animals is often very useful for distinguishing between different species. Studying the species compositions at different localities and depths along the MAR provides information about where different species live and how common they are in different areas. This information gives some clues to whether physical structures such as the ridge or the sub polar front create barriers for the distribution of different species.

Photo: Paal Oeyvind Aas
A. The two species Eucopia grimaldii (left) and Eucopia unguiculata (right).
B. These two species can easily be distinguished by studying the many spines that cover the telson of each individual. Photos: Pål Øyvind Aas

In addition to knowing which species the animals belong to, it can be useful to determine different population structures such as gender distribution, developmental stage and size of the individuals. This can be used for determining whether male or female, young or old, or individuals of differ sizes are distributed differently at different depths. Additional information on the time and date that the animal’s where captured can reveal whether different individuals migrate vertically between day and night.

Meet the MAR-ECO post-graduate students and their projects in the student profiles:

Dangerously delicious?
Inger Marie Tyssebotn
Bachelor student projects
HiÅ B.Sci. students
Bone Atlas
Amy Heger
MAR-ECO jigsaw
Vanda Carmo
Systematics project
David Rees
What are dolphins doing along the mid-Atlantic ridge?
Lise Doksæter
DNA from shrimp diet
Helene Axelsen
Krill on the MAR
Tom Letessier
Biology and distribution patterns of some deep-sea fishes
Inge Fossen
The distribution of Lophogastrida
Pål Øyvind Aas
Analyses pictures of deep-sea life
Nicola J. King
Food for thought. What do deep-sea fish have for dinner?
Guro Gjelsvik
Jellies - challenging objects to study
Aino Hosia
~ see also students & scholarships
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