Amphipoda is an order of animals that includes over 7,000 described species. They are particularly important as herbivores, detritivores, micropredators and scavengers in marine environments. Amphipoda was a significant crustacean taxa in pelagic and demersal trawls on the RV GO Sars cruise in 2004, and probably play important roles in the food web.
The amphipod taxonomist, Dr Georgy Vinogradov (P.P.Shirshov Institute of Oceanology and A.N. Severtsov Institute of Ecology and Evolution, Moscow) visits the Institute of Marine Research, Flødevigen near Arendal in southeastern Norway, 5 May-2 June, 2008. The objective of his visit is to identifiy amphipods collected on the MAR-ECO 2004 expedition to the mid-Atlantic Ridge on the RV “G.O. Sars”.
Amphipods were sampled from 54 stations along the mid-Atlantic Ridge with four types of gears (three pelagic trawls, and one demersal trawl). A total number of 187 mixed amphipod samples will be processed by Dr. Vinogradov during his visit.
Several of the identifed species are known to live their lives associated with gelatinous zooplankton (jellies, ctenophores, and thalicean tunicates), such as the huge deep sea hyperiid Megalanceola stephenseni (Fig 3).
Fig. 3. Megalanceola stephenseni
The pelagic amphipod fauna north of the Sup Polar Front (SPF) was numerically dominated by Themisto (Fig 4). South of the SPF, the “pram bug amphipod” (Phronima sedentaria, Fig 5) was abundant. This transparent deep sea hyperiid amphipod is particularly renowned for its house-building. It devours the internal soft body parts of salps which are modified to form open-ended barrels. Eggs and hatchlings are deposited as a saddle on the inner wall of the barrel.
Fig. 4. Themisto compressa Fig. 5. Phronima sedentaria
It has been claimed that Phronima served as an inspiration for the design of the “Alien monster” although there seems to be little evidence to support this claim. The original monster design was based on a previous painting by the Swiss H.R. Giger “Necronom IV”, that bears little resemblance to Phronima (source: Wikkipedia).