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Chrysosphaerella annulata compared with Chrysosphaerella coronacircumspina

Taxonomic Classification

Rank
Kingdom same	Chromista (أسناخ صبغية)	Chromista (أسناخ صبغية)
Phylum same	Ochrophyta (طحالب داكنة)	Ochrophyta (طحالب داكنة)
Class same	Chrysophyceae (طحالب ذهبية)	Chrysophyceae (طحالب ذهبية)
Order same	Ochromonadales (Ochromonadales)	Ochromonadales (Ochromonadales)
Family same	Paraphysomonadaceae	Paraphysomonadaceae
Genus same	Chrysosphaerella	Chrysosphaerella
Species	Chrysosphaerella annulata	Chrysosphaerella coronacircumspina

Evolutionary Relationship

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

Conservation Status

NE — Not Evaluated

NE — Not Evaluated

Physical Characteristics

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

Habitat & Geographic Range

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway and Sweden.

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway and Sweden.

Chrysosphaerella annulata is a colonial freshwater chrysophyte microalga in the genus Chrysosphaerella, class Chrysophyceae. Unlike unicellular loricate chrysophytes, Chrysosphaerella species form spherical or ellipsoidal free-floating colonies in which individual cells are embedded in a common gelatinous matrix. The individual cells bear long siliceous scales with distinctive ring-like or annular structures — referenced by the species epithet annulata — projecting outward from the colony surface, giving the colony a spiny appearance under microscopy. These siliceous scales are species-specific and their morphology, as revealed through electron microscopy, is the primary character for identifying Chrysosphaerella species. C. annulata has been recorded from Norwegian and Swedish freshwater environments, consistent with the Scandinavian emphasis in chrysophyte research and the high diversity of chrysophytes in boreal freshwater systems. Chrysosphaerella colonies are planktonic, inhabiting the limnetic zone of oligotrophic to mesotrophic lakes where they may form locally conspicuous populations during favorable conditions. The species uses chlorophylls a and c with fucoxanthin for photosynthesis, contributing to primary production. Chrysosphaerella scales can accumulate in lake sediments, providing a record of past community composition and environmental conditions. C. annulata has not been assessed under IUCN criteria and is classified as Not Evaluated. Its documentation contributes to understanding the diversity of colonial chrysophyte forms in northern European freshwater ecosystems.

Chrysosphaerella coronacircumspina is a colonial chrysophyte alga in the genus Chrysosphaerella, family Chromulinaceae. Its compound specific epithet corona-circumspina (Latin: crown of surrounding spines) references the distinctive arrangement of silica spines forming a ring or crown around each cell in the colony. Each cell in a Chrysosphaerella colony bears both flat siliceous scales and long, projecting spines, with the spine arrangement being species-specific and taxonomically diagnostic. The colonial organization is held together by organic matrix material, creating a spherical or semi-spherical aggregate visible under light microscopy. C. coronacircumspina is found in freshwater phytoplankton communities in Scandinavia, consistent with the broader distribution of Chrysosphaerella in cold-temperate and subarctic lakes. The silica structures produced by Chrysosphaerella cells are deposited in lake sediments upon cell death, creating millennial-scale paleoenvironmental archives. Chrysophytes are sensitive to lake acidification, nutrients, and temperature, making them useful climate proxies in paleolimnological research. The species has not been assessed for conservation status by the IUCN and is listed as Not Evaluated.

Shared Countries

Both species can be found in 2 countries:

🇳🇴 Norway 🇸🇪 Sweden