Day 13
12 february 2022
Last plankton net
Very early this morning the last plankton net of Martha was deployed. During the cruise, she collected samples with 6 nets. All bioluminescent planktonic organisms will be studied in the MIO laboratory to understand the origin of their bioluminescence. Many of them live in symbiosis with bacteria that produce this light.
To observe them on board, Martha placed them in natural conditions in a cold room at 13 degrees in complete darkness.
Today, she found some animals that were the wonder of the team!
Crédit photo : Nicolas Fromont - @nicolasfromontphoto
Baby squid
It's a juvenile squid measuring only a few millimeters!
Squids are part of the cephalopod family like octopus and cuttlefish. It's rare to observe them because they live mainly under 50 meters of depth. We consider ourselves very lucky to be able to admire this little being! He is preserved in seawater renewed in oxygen and he will find its freedom after some observations.
The colored spots on its body are pigmentary cells called chromatophores, they are at the origin of the color of the epidermis. Many species have those cells, but in cephalopods their color can change. The cells change their size and expand the contents of their pigmentary bag to pass from one shade to another, they can vary from orange to brown through red. Chromatophores are controlled by neuronal activity and can expand or contract in a few milliseconds!
Crédit photo : Marthe Vienne
An inspiring squid
Cephalopods also have iridescent chromatophores, among them the iridophores - which are also found in fish or reptiles.
These specialized cells don't function with a pigmentary bag but with reflecting crystals. These crystals are microscopic slides made from crystallized guanine. Guanine is a nucleic base of the DNA, it corresponds to the G of the 4 letters in the genetic code (ATCG). Its crystallized form reflects the light and allows to play with the different colors that compose it. Not bad, right?
The industry is inspired by this property to create the pearly effect of some paints or makeup. These are bio mimetically inspired products, like the artificial reef BathyReef which is inspired by the shape of internal tissues of ascidians ! The best designs are in nature !
Crédit photo : Marthe Vienne
Last dive for the Nautile
Today is the last use of the Nautile on the EMSO-LO site, with Jürgen from CPPM on board. Jürgen's mission is to accompany the Nautile pilots in the disconnection of the telescope of the ANTARES project (Astronomy with a Neutrino Telescope and Abyss environmental RESearch). This project is replaced by the KM3NeT neutrino telescope, mentioned at the beginning of the mission.
Neutrinos are elementary particles, without any electric charge and with a tiny mass, which circulate in the Universe. They travel everywhere in space and can cross the Earth through its core. Astrophysicists study the journey of these particles!
Neutrinos are produced during natural and common reactions, such as the fusion of two atomic nuclei, nucleus fission or radioactivity (beta type). For example, the reactions within stars, including our Sun, are powerful neutrino generators.
The study of these particles can provide information on a distant celestial origin. Their trajectory can lead researchers to a major event in the Universe, like a supernova !
But what is a neutrino telescope doing under the ocean?
These devices are placed in the depths of the Earth to seek a maximum of darkness to operate. Water also offers other advantages to astrophysicists, such as its high density and transparency, which make it a good observation ground.