Coccolithophorid vs Polar bear

Hymenomonas roseola compared with Ursus maritimus

Key Differences

Coccolithophorid is Not Evaluated while Polar bear is Vulnerable.

Taxonomic Classification

Rank	Coccolithophorid	Polar bear
Kingdom	Chromista (クロミスタ)	Animalia (動物)
Phylum	Haptophyta (ハプト藻)	Chordata (脊索動物)
Class	Prymnesiophyceae (Prymnesiophyceae)	Mammalia (哺乳類)
Order	Coccolithales (円石藻目)	Carnivora (ネコ目)
Family	Hymenomonadaceae	Ursidae (Bears)
Genus	Hymenomonas	Ursus (Bears)
Species	Hymenomonas roseola	Ursus maritimus

Conservation Status

Coccolithophorid

NE — Not Evaluated

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

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

Habitat & Geographic Range

Coccolithophorid

Habitat

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

Range

Distributed across Norway, Sweden, and United States.

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.

Coccolithophorid

Hymenomonas roseola is a marine coccolithophore in the class Prymnesiophyceae, belonging to the order Coccolithales—a group of single-celled phytoplankton celebrated for covering their cell surfaces with ornate calcium carbonate scales known as coccoliths. This species is notable for producing distinctive coccoliths with a characteristic architecture visible under electron microscopy. Like all coccolithophores, Hymenomonas roseola plays a significant role in oceanic biogeochemical cycles: the formation of calcium carbonate coccoliths drives the biological carbon pump by fixing inorganic carbon into mineral form, which sinks upon cell death to accumulate in deep-sea sediments. The species inhabits the photic zone of temperate to subtropical marine waters in the North Atlantic, Mediterranean, and Pacific regions, where it has been documented from coastal and open-ocean samples. As a photosynthetic organism, it requires sunlight for carbon fixation and typically blooms in stratified surface waters with adequate nutrients. Coccolithophore blooms can be so dense as to be visible from space as turquoise patches in satellite imagery. Hymenomonas species have also been noted for their ability to calcify in culture, making them useful laboratory models for studying coccolith biomineralization mechanisms and the potential impacts of ocean acidification, which threatens to dissolve calcium carbonate structures as seawater pH decreases. Its conservation status has not been formally evaluated.

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。