"Mystery Jelly" with clustered black objects - geograph.org.uk - 1560335

Autor:

Lairich Rig

Shortlink:

https://czwiki.cz/b/e3491

Zdroj:

Wikimedia Commons

Formát:

640 x 480 Pixel (119833 Bytes)

Popis:

"Mystery Jelly" with clustered black objects. The nature of a mysterious jelly found outdoors has caused much debate: http://www.bbc.co.uk/scotland/outdoors/articles/jelly/index.shtml

It is often found simply as a clear gel; see 1182111. In other cases, clusters of small round black objects are found associated with it, as illustrated here. As can be seen here, there were pinkish smears of blood on the surface, and even some remnants of blood vessels; this provides compelling evidence for an animal origin.

It was lying on a footpath, next to a puddle, in (as usual) a place where frogs can be found. Many have suggested that this material is from frogs taken by predators, and this seems to be the correct explanation; compare the fifth photo on a page at the Hainault Forest Website: http://www.hainaultforest.co.uk/7ReptilesandAmphibians.htm (my own photo therefore seems to show one of the convoluted end-parts of the oviducts).

The appearance of this substance changes over time: it absorbs water, becoming more transparent, and swelling a great deal (consider the volume of a mass of frogspawn, compared to the frog that lays it; it is therefore not surprising to learn that after frogspawn is laid, the gel around the eggs expands in water). The original compact mass often ends up broken into scattered blobs, as illustrated at 1024172 (note the black eggs there, too); the "clear gel" image (see link in second paragraph, above) is a still later stage, where all the eggs have been eaten (this is possibly what breaks up the gel into scattered pieces).

In short, I believe that the picture shows the two components of frogspawn: (1) the eggs (if these look smaller than expected, this may be because the jelly that usually surrounds them acts rather like a lens), and (2) the clear jelly, found here in an unexpanded state. Because, in this case, they were not laid as frogspawn, the two components were found in an unmixed state.

Other natural jelly-like substances are sometimes encountered outdoors; see https://www.geograph.org.uk/photo/1000481 for a partial list.

Of these, a few of the other possibilities that are sometimes suggested as the identity of the particular kind of "mystery jelly" that is shown in this photo can be discounted: jelly fungi, because they occur on wood; cyanobacterial colonies (Nostoc), which are not clear, but rather brown-green to green; the plasmodial stages of certain slime moulds, which do occur on vegetation, but which grow around and in intimate contact with it, whereas the mystery jelly shown here is quite separate in that it is lying on the ground, but can be picked up intact. Of course, these and other substances may account for some other kinds of natural jelly. See the link in the preceding paragraph for examples of all the organisms mentioned here.

Licence:

CC BY-SA 2.0

Credit:

From geograph.org.uk

Sdílet obrázek: