Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Why Mollusca Do Not Die On Land


Way out exists even from the most desperate situations. Water mollusca prove that statement. At first sight, they are absolutely unable to live without water, as they consist almost totally from water. However, this is only at first sight. Russian scientists have analyzed their data and the data from their colleagues who observed mollusca on the banks of various water bodies and have discovered the adaptation mechanisms these animals employ to live without water.

Water mollusca are used to being constantly thrown out by sea-waves on the shore, or the imminent high tide “forgets” to take mollusca along with it, or the native lake can dry up. Mollusca got accustomed to that and elaborated a lot of accommodation mechanisms that allow to survive on land for a long time – for up to a year. However, the term depends on atmospheric temperature: the higher the temperature is, the less chances the animal has to survive. Mollusca’s adaptation mechanisms were investigated by researchers of the Severtsov Institute of Ecology and Evolution Problems, Russian Academy of Sciences.

The water mollusc that remained on land has to solve two major problems: to retain moisture and to breathe in unusual conditions. While the mollusc is only starting to dry off, it is actively crawling and collecting food in reserve if it is available (it should be noted that even the mollusca that normally can only swim are crawling in these conditions). But moisture should be preserved for respiratory surface, otherwise the mollusc will be unable to breathe, therefore, some time later it passes to the second phase of its self-rescue. Special viscous liquid is excreted, the origin of the liquid is still unknown to researchers. The liquid serves as lubricant and does not allow the animal to dry up. To intensify the effect of water-retaining lubricant, some mollusca bunch into packs of 3 to 6 individuals and hide under stones, in the rock cracks – i.e., in the shadow.

The case is easier for the mollusca that have big shells and special folds or covers to close up the shell with. Then they turn out to be in a waterproof “house” and lose less moisture. However, it will soon be nothing to breathe in the “house”, and then chemical changes take place in the mollusc’s organism, these changes allowing to live without oxygen or interaction with the environment. The hemolymph (i.e. mollusc’s blood) protects the mollusc from being poisoned by products of such airless metabolism, calcium from the internal surface of the shell assisting the hemolymph. Approximately the same role is played by the so-called crystalline pedicel – the organ that can be apparently considered a strategic stock of food and oxygen.

The unlucky mollusca that are deprived of shells or whose shells are small have to bury oneselves into the soil – it is cooler there. Mollusca bury themselves so skilfully, as if they had spent all their life in the soil – sometimes deeper than 35 centimeters. If a small shell is still in place, then, having buried itself, the mollusc draws the body in the shell and excretes a protective film to close up the “entry”. It is interesting to note that mollusca are apparently great individualists: even representatives of the same species living in the same water body bury themselves at different depth, excrete different protective films, and some do not bury themselves at all. Nevertheless, whatever the mollusc does, whatever the shell it has to protect itself, it would lose moisture all the same: within a long drought the mollusc can “grow thin “ by 40 to 80 percent.

The respiration problem is also solved by water mollusca in different ways. When in water, some breathe with gills, some – with lung, and when on land they have to “absorb” oxygen by the entire body – that is possible due to the blood vessel network located close to the surface. Besides, combined respiration is common among mollusca, i.e. they can breath both by the atmospheric air and by the oxygen dissolved in water. This skill is inherent to, for example, freshwater mollusca that inhabit constantly drying up water bodies.

Sergey Komarov | alfa
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

nachricht Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Prototype device for measuring graphene-based electromagnetic radiation created

28.10.2016 | Power and Electrical Engineering

Gamma ray camera offers new view on ultra-high energy electrons in plasma

28.10.2016 | Physics and Astronomy

When fat cells change their colour

28.10.2016 | Life Sciences

More VideoLinks >>>