Aquarium – English

We humans have a natural curiosity for the unknown and the undiscovered. And so it is hardly surprising that a living space, which is shaped by a completely different medium, namely water, exerts an almost magical attraction on us. Our innate inclination to nature, which finds less and less fulfillment in an increasingly urbanized world, increases this need. A journey into this mysterious underwater world is made possible by a human invention that gives aquatic creatures a new home outside of their natural habitat and at the same time increases our knowledge and understanding about it: the aquarium.

The first of its kind opened over 160 years ago in London (1851), followed by Paris, New York, Hawaii, Berlin and on Helgoland (1902). The latter, for example, provided insight into the underwater world around Germany’s only offshore island in the North Sea. The island, which is 65 km far from the mainland, is made of red sandstone and subject to the tides. It is therefore characterized by a rocky floodplain, a rocky bottom, which has areas of life that are permanently, predominantly, temporarily or rarely covered by water due to ebb and flow. The resulting abundance of differently structured areas of life has led to zoning and thus to an above-average biodiversity of plants and animals.  The presentation of this and other complex ecosystems is the focus of today’s modern (large) aquariums. Mostly they show local aquatic habitats on the one hand, and on the other those of supraregional interest, such as the underwater world of the tropics. Of course, the location of each large aquarium (? 100,000 L) influences its individual design, so that the cooling or warming water either comes from the original habitat itself, i.e. the sea, lake or river, or is produced artificially on site in the aquarium. Artificial seawater – a technically feasible standard today – enables aquariums to have marine ecosystems far away from their natural occurrences, and make it tangible for visitors. Another factor that limits aquatic life, both in its natural environment and in aquariums, is the maintenance of specific water parameters. Therefore, organisms are individually adapted to these, according to their specific habitat and can only survive within certain parameter ranges.

In order to guarantee adequate water parameters ??in the aquarium, very complex and expensive technical systems are usually necessary and in operation today. A distinction is made between open, half-open and closed live support systems (LSS). The open systems draw water from the environment and return it after use and cleaning. This mainly applies to aquariums that only depict their surrounding habitat, i.e. seawater aquariums the on coast or inland aquariums at lakes or rivers. Aquariums with closed circuits are independent of their location because they artificially produce the required (sea) water. For this purpose, fresh water is mixed with the essential sea salts in the required proportions, checked for its properties and then released for use or made available to marine organisms. 

The technical effort required for this is an important factor with high costs in some cases, but at the same time enables aquariums to simulate increasingly complex ecosystems and make them accessible to visitors. This not only increases people’s interest in the underwater world, but also offers the opportunity to point out the increasing threats to specific habitats. Building materials such as concrete and acrylic glass have paved the way for today’s aquariums, which represent diverse worlds of experience. The use of acrylic glass has many advantages. It is significantly lighter than glass based on silicon dioxide (sand), more durable, easier to care for and, above all, more malleable, so that the manufacture and use of gigantic, flat or curved panels, tunnels and domes in today’s large aquariums have become obligatory. But an adequate home not only includes the right chemical and physical (so-called abiotic) conditions, but also the “ambience”, i.e. the biological structuring of the environment. All tanks of an aquarium are adapted to the specific needs of the individual species and represent a copy of its natural habitat. And the more lifelike the artificial habitat is, the healthier the living beings will be. Its well-being has the highest priority, as it is the basis of every sustainable and successful aquarium.

An aquarium tank that is supposed to document life on the rocky tideland will always have a rock-like structure, a kelp tank exhibits kelp and a coral reef tank presents different corals. The essential exhibit elements consist these days predominantly of artificial materials (i.e. water-resistant plastics) and often have a very detailed structure. The trained observer will, however, notice the difference with natural exhibits. The Helgoland Aquarium was also characterized by its special location, which allowed the use of natural exhibits. As part of a marine biology research institute the aquarium could utilize its infrastructure. Research divers delivered regularly brown algae as part of the authentic exhibits of the tanks. The authentic character of the tanks was emphasized by two further aspects: On the one hand, the use of natural sea water within the aquarium, the temperature of which was only a few degrees higher than outside, resulted in the same biorhythm as in the sea (increased activity in summer, reduced in winter). On the other hand, the introduction of various sea creatures, such as sea anemones or fish larvae, was possible without any further involvement, since the only water filtration method used was gentle sedimentation.In aquariums with closed cycles, in which the water is cleaned by means of sand pressure filters where the water is pressed through sand at high pressure, the chances of survival of these creatures are rather low. In aquarium tanks with species-appropriate water parameters and species-specific habitat design, its residents will benefit from good living conditions. But another factor has a decisive influence namely sufficient and species-specific feed otherwise, because hungry fish eat each other, at some point almost empty tanks would be the result. However, this also means that only well-fed fish can be found in aquariums, because they do not have to move long distances to get to new sources of food. However, spatial separation during feeding does play an important role in aquariums, namely in order not to confuse predators and potential prey, which may well live in the same tank, with a mutual taste. The successful operation of an aquarium requires excellent organizational and logistical planning in many ways in order to cover all aspects and implement appropriate measures. In the meantime, the general conditions for keeping more and more aquatic organisms are better known. Even species from the deep sea can be kept in aquariums, because many of them move from their traditional depths to the sea surface and back again in the course of their daily foraging for food, so they are adapted to pressure fluctuations. Much has not yet been explored, however, and the constant conditions in the large aquariums in particular provide excellent opportunities for researching plants and animals. The huge tanks with a capacity of millions of liters – such as the central tank of the S.E.A. Aquarium in Singapore with 18 million liters – also provide space for species conservation. And as a place of experience and understanding, aquariums are destined for an intentional transfer of knowledge about the presented habitats and its exploration. They also offer the possibility of establishing science as a central, institutional component of future aquarium generations, right up to active research shaped by the visitor (citizen science) in collaboration with established scientists. Science to experience and shape. As interdisciplinary competence centers, aquariums can and will make a decisive contribution to the understanding and preservation of our planet and its inhabitants. Come on and join us on a fascinating under water journey to better understand the world above.

Insights into the methodology, the experimental setup and implementation in man-made water bodies

Science – Because of knowing the reasons

“Rerum cognoscere causa – Because of the recognition of the reasons” as the motto of the Berliner Tagesspiegel describes the purpose of science in a perfect way. Because it asks for the context given by nature and humans, and tries to derive general knowledge that can be used to optimize life. This principle originates in nature, because adaptation based on knowledge acquired through curiosity and experience ensures survival. This adaptation process has contributed significantly to evolution and thus to a knowledge-based, improved existence. Due to that we owe our relatively high standard of living today and the fact that the human lifespan on this planet is getting longer. Since the increase in the quality of life to the present day has largely been accompanied by an increasing use of natural resources, more efforts will be required in the future to make them sustainable in order to prevent us humans from depriving ourselves of our livelihoods as the only species on earth. The expansion of human habitats, climate change and loss of biodiversity are central phenomena which prove the anthropogenic influence. But in this situation, SCIENCE makes a decisive contribution to responsible use of the environment through RESEARCH. 

So, what is Science and how does it work?

The basic approach is to formulate a null hypothesis and to check out by means of experiments and their results whether the null hypothesis can be confirmed (verification) or falsified (not confirmed; falsification).

How are Investigations or Experiments carried out?

Before each investigation, test or experiment, detailed planning must be carried out, in the course of which the test set-up, implementation and evaluation are determined. That means the number of objects to be examined, the necessary equipment, the necessary personnel (scientists), as well as the evaluation methodology are determined and structured. For meaningful investigations or experiments it is also of crucial importance to vary only one parameter – which influences the possible result – and to keep all the others constant. Otherwise it is not possible to understand which parameter led to the change in results. In addition to an adequate experimental setup, the execution (repeated measurements) must always be subject to the same procedure. Otherwise, non-reproducible results may result from the changed process. It is also important to ensure that the measurements that are made do not affect the result. Since they always do this according to HEISENBERG, it is also necessary to always carry out all measurements in the same way so that they always appear as the same, quasi-system-inherent factors and can therefore be neglected. And finally, the evaluation of the results must be performed in a suitable manner. This means that you have to be aware that almost every form of a statistical evaluation method can contain a reduction in information, i.e. results are neglected because they are not considered with one or the other evaluation method. Furthermore, investigations or tests can sometimes only be performed with very limited test resources, so that only a certain, limited number of repeat tests (experiments) is possible. In advance (i.e. when planning the experiment), it must be ensured that all the desired information is obtained. The complexity of scientific investigations is often much greater than what is visible from the often very compressed results. The difficult conditions under which scientific investigations are executed, are also often underestimated.