vs Polar bear

Coelosphaerium subarcticum compared with Ursus maritimus

Key Differences

is Not Evaluated while Polar bear is Vulnerable.

Taxonomic Classification

Rank		Polar bear
Kingdom	Bacteria (Bacteria)	Animalia (動物)
Phylum	Cyanobacteria (藍藻)	Chordata (脊索動物)
Class	Cyanobacteriia	Mammalia (哺乳類)
Order	Cyanobacteriales	Carnivora (ネコ目)
Family	Microcystaceae	Ursidae (Bears)
Genus	Coelosphaerium	Ursus (Bears)
Species	Coelosphaerium subarcticum	Ursus maritimus

Conservation Status

NE — Not Evaluated

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute		Polar bear
Diet	—	Carnivore
Average Lifespan	—	25 years
Average Length	—	2.4 m
Average Weight	—	450.0 kg

Habitat & Geographic Range

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway and Sweden.

Polar bear

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 4 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found in Norway. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

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.

Polar bear

地球上で最大の陸上肉食動物であるホッキョクグマは700kgを超えることがあり、カナダからロシアまでの北極海氷域全体に分布する。ワモンアザラシとヒゲアザラシを狩るために海氷に依存する高度に特化した海洋哺乳類である。広大な距離を泳ぐことができる優れた泳者でもある。脆弱種に指定されており、気候変動による急激な北極海氷の消失で個体群が深刻な圧力を受けている。