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Coelosphaerium dubium compared with Coelosphaerium kuetzingianum

Taxonomic Classification

Rank
Kingdom same	Bacteria (Bacteria)	Bacteria (Bacteria)
Phylum same	Cyanobacteria (Cyanobacteria)	Cyanobacteria (Cyanobacteria)
Class same	Cyanobacteriia	Cyanobacteriia
Order same	Cyanobacteriales	Cyanobacteriales
Family same	Microcystaceae	Microcystaceae
Genus same	Coelosphaerium	Coelosphaerium
Species	Coelosphaerium dubium	Coelosphaerium kuetzingianum

Evolutionary Relationship

and share a common ancestor at the Genus level: Coelosphaerium.

Conservation Status

NE — Not Evaluated

NE — Not Evaluated

Physical Characteristics

Attribute
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Habitat

Native to Asia and Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, Sweden, and Taiwan.

Habitat

Native to Asia and Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, Sweden, and Taiwan.

Coelosphaerium dubium is a colonial planktonic cyanobacterium in the family Merismopediaceae, named for the taxonomic uncertainty surrounding its morphological boundaries with related species in the genus. Like its congeners, it forms spherical, gelatinous mucilaginous colonies in which cells are distributed at the periphery of a central hyaline matrix. The genus Coelosphaerium has historically been defined by gross morphological characteristics—colony shape, cell arrangement, and mucilage properties—but molecular phylogenetic analyses have substantially revised understanding of cyanobacterial diversity and systematics within this group. Coelosphaerium dubium has a relatively broad geographic distribution compared to some congeners, with records from freshwater bodies in Denmark, Norway, Sweden, and Taiwan, suggesting either a wide ecological tolerance or cryptic species diversity within the taxon. It inhabits lentic and slow-flowing freshwater environments, particularly stratified lakes and ponds where thermal and chemical gradients allow cyanobacterial cells equipped with gas vesicles to adjust their buoyancy and optimise light exposure. As a primary producer in these aquatic ecosystems, it contributes to nutrient cycling and forms part of the phytoplankton community grazed by zooplankton. No formal conservation assessment has been undertaken for this species by the IUCN.

Coelosphaerium kuetzingianum is a colonial planktonic cyanobacterium in the family Merismopediaceae, named in honour of the nineteenth-century German phycologist Friedrich Traugott Kützing, who made foundational contributions to the study of algae and cyanobacteria. The species forms spherical to globular mucilaginous colonies with cells arranged near the periphery of a clear gelatinous matrix—the characteristic architecture of the genus. Individual cells are small, typically 2–5 micrometres in diameter, and possess gas vesicles that confer buoyancy regulation, enabling the organism to position itself advantageously in stratified water columns. Coelosphaerium kuetzingianum has been recorded from freshwater lakes, reservoirs, and ponds across temperate northern Europe, including Denmark, Norway, and Sweden, as well as from Taiwan, indicating a broad latitudinal tolerance. Its occurrence in both boreal and subtropical settings suggests morphological plasticity or the presence of distinct ecotypes within the species concept. As with other members of the genus, it participates in aquatic food webs as a primary producer and is consumed by filter-feeding zooplankton such as cladocerans and rotifers. Eutrophication resulting from agricultural nutrient loading can stimulate cyanobacterial growth in affected water bodies. No IUCN conservation assessment has been undertaken for this planktonic cyanobacterium.

Shared Countries

Both species can be found in 4 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden 🇹🇼 Taiwan