The nano sea water aquarium - revisited

It appears that our nano sea water aquarium is widely underestimated. Therefore we would like to repeat its fascinating characteristics: first of all we call it "Rocharium", as it is just a simple empty polystyrene "Ferrero Rocher" chocolate candy box. Whereas other people are calculating 500 US $ per month in order to maintain a big sea water aquarium ours is perfectly free! No need for feeding, no need for electricity (no pumps, no artificial illumination ...). Wow!

Fig 1.: Our favorite sea water aquarium - just an empty polystyrene box! The aquarium shown here is filled with sea sand taken from the Adriatic Sea near Rovinj, Croatia, plus a little bit of local sea water. The sand can be collected from the wet shoreline or, alternatively from the ground of the ocean, at a few meters' depth. The thickness of the sand layer should be ca. 1 cm to 2 cm, the thickness of the water layer a few centimenters.

This perfectly transparent box has rounded edges - a nice feature which will help in order to keep the corners clean and easy to reach by means of a pipette. As the bottom part is made of one peace we do not risk sudden breakage and water loss like the one encountered with bigger (glued) aquaria. Due to the cover no water can evaporate. As a consequence the water volume and salt concentration will remain constant for many weeks, even months. There is only one important restriction to be taken into consideration: this type of aquarium is a minimalistic aquarium - few inhabitants and tiny inhabitants only.
Not allowed is anything living with a body size beyond a few millimeters: fishes, hermit crabs, large shells and algae - all of these might ruin our well-balanced equilibrium of life in the micro aquarium. Direct sunlight and excessive heat are strictly forbidden whereas shell gravel and clean, grainy sand are perfectly welcome.

When following these precautions our sea water aquarium can stay in equilibrium for many months, in some cases even several years. Of course there are no fishes and no corals to be seen with the naked eye but there will be a tremendous wealth of tiny organisms which can be studied by means of the microscope. And you might be hundreds of miles away frome the sea!

Teachers and museum personel thus can present marine life at any given moment, just by projecting a microscopic image onto a wall. Adieu formalin, welcome life! The aquarium can easily be moved to another place and it is always ready for use. And, strange enough, it is best to provide no additional food at all.

Even the sea water itself is full of surprises when letting evaporate tiny droplets of it on a slide. Just have a look at the following example:

Fig. 2: Microscopic image of sea salt after evaporation of sea water.

And yes, also this time the tardigrades were more clever than we had thought: after 3 months (!) of search we finally found a water bear within our aquarium. It had remained undetected even within this small water volume. This is helpful in order to appreciate how many wonders can be found outside in the millionfold bigger volume of the Adriatic Sea!

Fig. 3: Halechiniscus living in the micro sea water aquarium.
Body length ca. 0.15 mm.

Fig. 4: Same as fig. 3, detail, front part of body.

Fig. 5: Same as fig. 3, detail, backside with stomach-intestine region.

Fig. 6: Same as fig. 3, detail, claws of one of the hind legs.

Literature (sorry, in German)

Walter Neubert: Geburt, Leben und Tod eines Rädertierchens (translated: birth, life and death of a rotifer). Mikrokosmos 83 (1994) p. 17 - 30.

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
The Water Bear web base is a licensed and revised version of the German language monthly magazine  Bärtierchen-Journal . Style and grammar amendments by native speakers are warmly welcomed.

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