AMPHIPOD MAKES ALUMINUM ARMOR TO SURVIVE IN DEEP-SEA ENVIRONMENTS

The deep-sea amphipod Hirondellea gigas inhabits the deepest regions of the oceans, under extreme high-pressure conditions, low temperature and high acid levels that dissolve its  exoskeleton, making them vulnerable to pressure and predators. The mechanisms by which this amphipod adapts to its high-pressure environment remained unknown, until now. Scientists have discovered how Hirondellea gigas can survive in the deepest part of the ocean: with aluminum suits of armor.

Researchers analyzed H gigas specimens collected from the bottom of the Challenger Deep, at more than 10,000 meters below the surface of the ocean, and found a layer of aluminum hydroxide gel covering the surface of its exoskeleton. Unlike other metals, aluminum isn’t abundant in ocean water, making it hard to source as a building material, it is, however, abundant in ocean sediment, where Hirondellea gigas lives.

- Deep-sea amphipod specimen captured from the Challenger Deep. The scanning electron microscopy shows calcium (red) and aluminum (green) are found on the surface.

According to researchers, these deep-sea amphipods eat sediments and detritus, and can made aluminum hydroxide gel as sub product of its diet, and this gel covers the body to protect the amphipod.  This aluminum gel is a good material for adaptation to such high-pressure environments. 

The species name “gigas” refers to the organism’s distinctively large body size among the amphipods. Amphipods are common inhabitants at great depths and serve as scavengers, and recently, deep-sea amphipods were caught eating microplastic a extremely depths.

• Photo:  Alan Jamieson.
• Reference: Kobayashi et al., 2019. An aluminum shield enables the amphipod Hirondellea gigasto inhabit deep-sea environments . Plos ONE

[Photo description: a single amphipod. These crustaceans have laterally compressed bodies, resembling a dog flea, but much larger in size.]