The Life We Cannot See

And last but not least: we do not have idea yet, what it could be. But maybe can you recognise what kind of organism it is and give us an answer or clue? And last but not least: we do not have idea yet, what it could be. But maybe can you recognise what kind of organism it is and give us an answer or clue?

Ocean is not only home to wildlife that we can observe with our own eyes, such as big mammals, fishes and seaweed. There are also small living organisms, which we do not always know about, because we do not see them with our naked eyes.

In Ocean Science, to see beneath the ocean surface, the Underwater Vision Profiler (UVP) can help us. It has a pressure-safe underwater camera, which can take images of Plankton and particles down to 6000 m depth. UVP is used to quantify the vertical distribution of macroscopic particles and zooplankton > 100 mm in size, and it takes images during the entire downcast with a frequency of 20 Hz. Over all, it means that 1 image is taken every 5 cm at the maximum lowering speed of 1 m/s. It has also two LED-flashes, which are coupled to the camera. These special lights flash many times per second and illuminate a volume of about 1 litre water between the lights, because in deeper waters there is no sunlight, but we still want to have a good, high resolution picture.If we talk about small living organism in the ocean, then we usually mean Plankton, which are probably one of the most underrated organisms in the world. Although they are very important to ecosystems, still most of us know little about them. 

Picture of UVP, made by R.Kiko (https://planktonid.geomar.de/en/UVP)
Picture of UVP, made by R.Kiko (https://planktonid.geomar.de/en/UVP)

For example: They are natural carbon sinks. When they die, they sink and transfer the carbon incorporated in them to the bottom of the ocean, trapping them for thousands of years. There are two main types of plankton: phytoplankton and zooplankton. 

Phytoplankton: Plant plankton or photosynthetic organisms that turn sunlight and carbon dioxide into energy.

Zooplankton: Animal plankton feed on phytoplankton and are in turn, eaten by other marine animals, like the fish.

During the research cruise of M159, we have captured some amazing pictures, which show us some of the living organisms found below the sea surface !

First we have “Chaetognatha” commonly known as arrow worms. They are found in all marine waters, from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most them are transparent and are torpedo shaped, but some deep-sea species are orange. They range in size from 2 to 120 millimetres.
First we have “Chaetognatha” commonly known as arrow worms. They are found in all marine waters, from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most them are transparent and are torpedo shaped, but some deep-sea species are orange. They range in size from 2 to 120 millimetres.
Sometimes, a fish swims by and tries to get our attention.
Sometimes, a fish swims by and tries to get our attention.
And last but not least: we do not have idea yet, what it could be. But maybe can you recognise what kind of organism it is and give us an answer or clue?
And last but not least: we do not have idea yet, what it could be. But maybe can you recognise what kind of organism it is and give us an answer or clue?

Written by Ilmar Leimann, GEOMAR 2019

One thought on “The Life We Cannot See”

  1. The last organism I would say either belong to the Chelicerata (Pantopoda), because it seems to have a dichotomous body (Prosoma and Opisthosoma) and four paired two-parted extremities. However, the size of the body and the mandible look like extremity perhaps on the second part three-parted body speak more for an organism belonging to the Crustacea. http://www.marinespecies.org provide a continously increasing list of species

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