Where Is The Aleutian Trench

Aleutian Trench - Aleutian Amphipod Heaven

Our prowl examining the Aleutian Trench will soon be over, we take finished the last station, packed up the labs, and now even stacked everything into the shipping containers. What is left then? All the residue of the science!

We take lots and lots of samples preserved in different ways (ethanol, frozen, RNA-after, formalin or dried) and we already take Deoxyribonucleic acid-extracts of some. We accept associated data from each station (h2o temperature and salinity, sediment information, and bathymetric info), and for many specimens we have a alive (or "most live") photo. The residual of the work volition have to be done at abode – in our labs on land, where we accept access to other infrastructure, and non least – where the lab does not move.

We can likewise start to depict the beginning preliminary conclusions. Preliminary is an of import word here, every bit it is impossible to get the total motion-picture show before we can look at the entire samples – and both time-constraints (at that place are just and so many hours in each twenty-four hour period) and technical constraints (that moving deck in the labs on the transport, for instance) prevent us from doing that on lath.
One of the preliminary conclusions we tin can draw is that the Aleutian Trench seems to be an Amphipod Heaven. In the samples nosotros have worked with so far, nosotros have approximately 70 different species of these (mainly) small crustaceans, and they outnumber the closely related Isopoda – both in species and number of specimens. This is rather unusual in the deep sea. Non that the amphipods are there and thrive, but that they outnumber the other small crustaceans so much.
Why could at that place exist then many amphipods in this specific trench? We don't know for certain, merely we can speculate. It might be that the amphipods "came hither first" – so filled upwardly available habitats earlier other species who might inhabit the same habitats came effectually. Or it might be that they take better to the soupy sediments we have establish in the lesser of the trench. Or most possibly another reason we have not thought virtually yet.
Amphipods (like isopods, tanaids, cumaceans and mysids – other crustacean groups nosotros have also had in our samples) are peracarid crustacea. They are grouped together because they have a breed-pouch where their fertilized eggs are kept through all stages during their reproduction, until they come out as small juveniles. This separates them from the other crustaceans, who permit their eggs or larvae float freely with the water currents for some time during the development. Such a life-history strategy helps spreading a species to larger geographic areas, and the peracarids are more than "home-bodies". Most of them are also non very skillful swimmers (but a certain fraction is!).
Not beingness very adept at spreading over wide geographic areas is one of the drivers of speciation – the "catastrophe up as carve up species" after a while considering groups get geographically isolated and small genetic changes happen all the time. The Aleutian Trench is ane of the older trenches, it started sometime betwixt 150–100 one thousand thousand years ago. Even giving the fauna some fourth dimension to become to the new trench and existence able to live there, this gives the fauna here a lot of fourth dimension to evolve and species to evolve locally.
So – we take a lot of different amphipods to examine when we get dwelling. This part of the deep bounding main in the N Pacific has non been examined very much before, especially the deepest, hadal, areas. Nosotros are quite sure that our samples will give united states several heady species to work with. Some of them might even exist new to science. That is not the aforementioned as "new for the world" – only that no scientists take examined them before. So the Aleutian Trench has been an amphipod heaven for us every bit well.

… and those overnice scientific papers about the amphipods? If you lot requite the states a piffling time in our home labs, we are certain they volition come likewise. Amphipod heaven for everyone!

Dr. Anne Helene Due south. Tandberg and Dr. Anna K. Jażdżewska