vs

Coelosphaerium dubium compared with Coelosphaerium subarcticum

Taxonomic Classification

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

Evolutionary Relationship

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

ดู: Genus: Coelosphaerium

Conservation Status

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 Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway and Sweden.

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 subarcticum is a colonial planktonic cyanobacterium in the family Merismopediaceae, as its epithet suggests, with distribution records concentrated in subarctic and boreal freshwater environments of Scandinavia, specifically Norway and Sweden. The species forms spherical mucilaginous colonies with peripheral cell arrangement typical of the genus, and its adaptation to cold water temperatures distinguishes it ecologically from congeners that prefer warmer, more eutrophic conditions. Subarctic lakes and ponds are characterised by low temperatures, ice cover for much of the year, and typically oligotrophic to mesotrophic conditions with relatively low nutrient levels. In such settings, cyanobacteria including Coelosphaerium subarcticum contribute to primary production during the ice-free summer season when available light and temperatures support photosynthesis. Gas vesicles in the cells enable buoyancy regulation, allowing colonies to rise toward surface light layers during calm conditions. Arctic and subarctic freshwater ecosystems are among the environments most sensitive to climate-driven changes, with warming temperatures extending the growing season, altering ice regimes, and potentially enabling southerly species to expand northward while cold-adapted taxa face range contraction. No formal IUCN conservation evaluation has been conducted for this species, as is typical for planktonic microorganisms at this taxonomic level.