vs Polar bear

Chrysochromulina mactra compared with Ursus maritimus

Key Differences

is Not Evaluated while Polar bear is Vulnerable.

Taxonomic Classification

Rank		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	Prymnesiales (Prymnesiales)	Carnivora (ネコ目)
Family	Chrysochromulinaceae	Ursidae (Bears)
Genus	Chrysochromulina	Ursus (Bears)
Species	Chrysochromulina mactra	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.

Chrysochromulina mactra is a marine haptophyte microalga belonging to the genus Chrysochromulina, class Prymnesiophyceae. The epithet mactra, meaning kneading trough or trough-shaped vessel, describes a morphological feature of the organism — likely the shape of a scale element or cellular structure visible through electron microscopy. Within Chrysochromulina, fine-scale ultrastructural characters of the cell surface and appendages are the primary basis for species identification, making high-resolution electron microscopy essential for taxonomic work. C. mactra has been recorded from Norwegian coastal marine environments, a region that has historically served as a major source of newly described haptophyte species due to focused research programs and the ecological richness of Norwegian fjord and shelf waters. These environments are influenced by cold North Atlantic currents and seasonal nutrient dynamics that support productive phytoplankton communities in which nanoplankton species like C. mactra play significant roles. As a member of Prymnesiophyceae, the species possesses chloroplasts with chlorophylls a and c and fucoxanthin-type pigments, enabling photosynthetic carbon fixation. The coiling haptonema is a diagnostic feature of Chrysochromulina distinguishing it from related genera including Prymnesium and Haptolina. C. mactra has not been formally assessed under IUCN criteria and is listed as Not Evaluated. As with most marine nanoplankton, its population status and extinction risk cannot be meaningfully quantified with current survey methods.

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。