Nostoc pruniforme
Pond plums ( Nostoc pruniforme ) at fishpond
The pond plum ( Nostoc pruniforme ), also called water or Seepflaume, is a süßwasserbewohnende type of cyanobacteria that forms conspicuous colonies in the form of gelatinous balls. This recall in appearance and external consistency something on a fruit, such as a grape or a small plum. It should be noted that such or similar gelatinous beads may be due to water or to other organisms, and that the type Nostoc pruniforme a total rare phenomenon.
Features
Nostoc species consist of long, unbranched, flexible filaments or cell lines. The individual cells of each filament are spherical to barrel-shaped and about 5 microns in size. The cell chains contained in sections one or more brownish- yellow heterocysts, which are responsible for nitrogen fixation. The thread cords are often twisted around each other and form a common stock in a spherical jelly. In the pond plum these balls can reach a diameter of about one to two centimeters. Externally, they have a thin, rough, brown - green skin; inside they are made macroscopically from a soft to firm - gelatinous, semi-transparent to milky turbid mass.
Occurrence
Pond plums are cosmopolitan spread and come in lakes and ponds benthic ( staple ) free floating or on muddy banks before. The striking balls sometimes accumulate by flow or wave drift at certain points of the lake bed. Nostoc pruniforme is rich in fish, quite clean, mesotrophic to slightly eutrophic inland waters and for example, was once common in northern Germany. Today you can find them there only scattered to rare; in Europe it is now regarded as an endangered species, the regional pond plum is even considered to be threatened with extinction.
Possible confusion
Spherical gelatinous stock, which are found in waters along its banks or on sickerfeuchtem bottom are formed of very many single-celled colonies, including of some other cyanobacteria. Various other Nostoc species, for example, this produces much more frequently than the pond plum treated here. Also, species of the genus Gloeotrichia as G. echinata, forms several millimeters large gelatinous balls that float freely in the water. In these, the radially arranged trichomes stand out from the camps, so that they have a hairy or spiky appearance.
Some green algae ( Chlorophyta ) forms by combining overlays also gelatinous conglomerates. These so-called coccoid green algae include those of the genus Haematococcus or even in streams very common alga Chaetophora pisiformis, up to pea-sized, dark green, hemispherical to spherical thalli from a tough, cartilaginous gelatinous mass forms. Often observed in the aquatic environment are also green, irregularly shaped, gelatinous structures, which may be colonies of, among other ciliates ( Ciliata ) or the rotifer Conochilus.
The probability that one about the discovery of floating or adherent greenish " Glibberkugeln " in the garden pond actually has plums pond in front of him, is already due to their rarity and specific environmental requirements, however, very low. In most cases, it is likely to involve cell colonies of other species. Their unequivocal determination is only microscopically usually possible.