Cosmarium (von griechisch kosmarion „kleiner Schmuck“) ist der Name einer mit zirka 1000 beschriebenen Vertretern relativ artenreichen Gattung der Zieralgen. Die Gattung gehört zur Familie der Desmidiaceae.
Cosmarien bestehen aus zwei meist 5 bis 50 µm großen Halbzellen, die durch einen sogenannten Isthmus, der den Zellkern enthält, verbunden sind. Im Gegensatz zur ähnlichen Gattung Micrasterias sind die oftmals nierenförmigen Halbzellen nicht eingeschnitten oder gelappt. Die Zellwände sind jedoch bei zahlreichen Arten in charakteristischer Weise skulpturiert, so dass leere Zellwände abgestorbener Cosmarien als Bestimmungsmerkmale genutzt werden.
Sie tragen im Gegensatz zu den Zellwänden der ähnlichen Gattungen Staurodesmus, Staurastrum und Xanthidium niemals Stacheln. Neben diesen Merkmalen dienen vor allem Zellgröße, Breite und deren Verhältnis als wichtige Erkennungsmerkmale. Cosmarien kommen meist in relativ sauberem, weichem Wasser vor und gehören daher z. B. zur Flora der Moore. So gelten Arten wie Cosmarium cucurbita und Cosmarium pygmaeum als sphagnophil. Neben Arten, die eng an bestimmte Lebensbedingungen gebunden sind, gibt es andere, die verbreiteter vorkommen und z. B. kleine Tümpel oder feuchte Erd-, Kies- und Sandplätze besiedeln. Da Biotope mit sauberem weichem Wasser seltener geworden sind, gehören inzwischen zahlreiche Cosmarium-Arten zu den gefährdeten Arten (vgl. Rote Liste gefährdeter Arten).
Cosmarium vexatum
Cosmarium quadratum (68 × 37 µm)
Cosmarium pseudamoenum (48 × 25 µm)
Cosmarium (von griechisch kosmarion „kleiner Schmuck“) ist der Name einer mit zirka 1000 beschriebenen Vertretern relativ artenreichen Gattung der Zieralgen. Die Gattung gehört zur Familie der Desmidiaceae.
Cosmarium is a genus of freshwater organisms belonging to the Charophyta, a division of green algae from which the land plants (Embryophyta) emerged.[1][2]
In this large genus the cells are very variable. All are constricted in the middle leading to its bi-lobed appearance;[3] the two halves are called semicells. Cells come in a variety of different shapes. The cell wall may be smooth or ornamented with spines, granules, scrobiculations (pits), or pores. Cells are generally flattened.[4] Cells usually have one or two chloroplasts filling the cell; each chloroplast contains pyrenoids, typically one or two.[5]
Cosmarium quadratum, with a smooth cell wall
Cosmarium pseudamoenum, with a granulated cell wall
Species identification of Cosmarium depends on the shape of the cells and their ornamentation, and can be difficult.[4] In addition, the genera Actinotaenium and Euastrum can be similar to various species of Cosmarium. Actinotaenium is generally circular in cross section, and Euastrum usually (but not always) has a notch at the tip of each semicell.[4]
Cosmarium is the largest genus of desmids, with over 1,000 species. It is an artificial genus: the defining characteristics of the genus are vague and arbitrary, and there are some species that are intermediate between several different genera. It is also not monophyletic, as molecular phylogenetic studies have shown that the form of Cosmarium evolved independently many times over. Despite this, the genus is still in use, because there is no known way of classifying desmids in line with their evolutionary history.[6]
Cosmarium and other desmid genera tend to prefer oligotrophic, somewhat acidic water habitats,[4] but some species exist in more eutrophic and/or basic habitats. Some species, which are small and mostly plain, form a community known as a "Cosmarietum"; these may be further associated with a community of Closterium species forming a Cosmarietum-Closterietum association.[5]
Cosmarium is a genus of freshwater organisms belonging to the Charophyta, a division of green algae from which the land plants (Embryophyta) emerged.
Cosmarium é um gênero de algas microscópicas da família Desmidiaceae,[2] sempre possuindo uma constrição central com bastante variações na morfologia das espécies. A sua reprodução é tanto sexual como assexual. Na reprodução assexual rompe-se a união das metades e cada metade formará uma nova alga.
Cosmarium é um gênero de algas microscópicas da família Desmidiaceae, sempre possuindo uma constrição central com bastante variações na morfologia das espécies. A sua reprodução é tanto sexual como assexual. Na reprodução assexual rompe-se a união das metades e cada metade formará uma nova alga.
Cosmarium, genellikle tatlı sularda yaşarlar. 20 - 110 mikrometre uzunluğunda, tekhücreli ya da ipliksi yapıdaki alglerdir. Her hücrede, farklı biçimlerde olabilen en az bir kloroplast bulunur. Üreme işlevini yerine getirecek hücreleri, karşılıklı geçerek sitoplazmalarını birbirlerine aktardıklarından, kavuşur su yosunları da denir.
Su yosunlarıler ile ilgili bu madde bir taslaktır. Madde içeriğini geliştirerek Vikipedi'ye katkıda bulunabilirsiniz. Cosmarium là một chi Song tinh tảo trong họ Desmidiaceae.[1]
Phương tiện liên quan tới Cosmarium tại Wikimedia Commons
Cosmarium là một chi Song tinh tảo trong họ Desmidiaceae.
장구말은 물먼지말과의 장구말속(Cosmarium)을 이룬다. 연못이나 늪과 같은 괴어 있는 물에서 자란다. 접합조류로 식물체는 단세포이며, 구형 또는 타원형이다. 몸의 중앙부가 잘록해서 이것을 경계로 대칭형의 반쪽 세포가 2개 포개져 있는 모양이다. 세포 표면은 울퉁불퉁한 돌기가 나 있는 것이 보통이며 2겹으로 되어 있는 세포벽의 안쪽은 셀룰로오스, 바깥쪽은 셀룰로오스 외에 여러 다른 물질을 함유한다.
