Translated material
The flight of algae
Oceanographers from the Higher School of Oceanography of the University of Rhinod (USA) for the first time observed the behavior of avoiding predator in microscopic seaweed ( Heterosigma Akashiwo ) . The article appeared in the September issue of PLOS magazine One .
“It is well known that phytoplanktonic organisms can control their movement in water, heading towards the world or nutrients,” says the doctor of the university and one of the authors of the article by Susanne Menden-deuer. - It turned out to be new that they were able to respond to predators, floating away from them. We do not know other similar cases in plants. ”
The discovery was made by chance. Studying the three-dimensional interactions of the predator type occurring in the ocean- the victim between phyto and zooplankton, the researchers drew attention to the fact that phytoplankton h . Akashiwo In the presence of predatory ciliates ( Favella SP . ) He began to move differently. Its swimming speed increased by 38%, and the speed of vertical motion was 29% compared to control (filtered by sea water). A series of laboratory studies showed that phytoplankton runs away not only in the immediate vicinity of predators, but also in water containing them some time ago. “Fitoplankton reacts so sensitively to the presence of a predator that he can even run away from the slightest smell inherent in them,” Menden-Do iter explains. When scientists provided phytoplankton as asylum with a lower salinity of sea water intolerant for ciliates, phytoplankton moved towards the shelter. An important question raised by the researchers is how these interactions affect the survival of the type of victim. Proceedings of unicellular zooplankton are the most important factor in phytoplankton in the ocean, and flight helps seaweed to survive.
Predators eat all phytoplankton per day, but if there is a shelter, the number of population h . Akashiwo can double in 48 hours. In most cases, a rapid increase in the number of microscopic algae to millions of cells per liter favorably feeding them inhabitants of the water world. The disadvantage of the uncontrolled growth of the population of microscopic algae is a change in the color of the water. Under special conditions (for example, in closed bays), flowering can become so dense that it contributes to the death of fish and invertebrates due to a strong decrease in oxygen. Some types of phytoplankton can produce toxins, thereby causing huge damage to maricultural farms. Their admission to food chains causes the death of marine mammals, birds, fish. Scientists believe that running away from predators is another important factor in the spread of flowering in the ocean, which can not always be explained by the characteristics of growth and the availability of nutrients. It is possible that the relationship of the phytoplanktone-victim and zooplankton-predator plays an important role here.
It is not yet clear how common such behavior is and how many other types of phytoplankton are fled from predators.
Tatiana Borisova
www.plosone.org/article/info%3adoi%2F10.1371%2fjournal .0046438
Harvey El, Menden-Deuer S (2012) Predator-induced
Fleeing Behaviors in Phytoplankton: A New Mechanism for
Harmful Algal Bloom Formation? PLOS ONE 7 (9): E46438.
Doi: 10.1371/Journal.pone.0046438