Clustered Stonewort vs common bubble snail

Tolypella glomerata compared with Akera bullata

Key Differences

Clustered Stonewort is Vulnerable while common bubble snail is Least Concern.

Taxonomic Classification

Rank	Clustered Stonewort	common bubble snail
Kingdom	Plantae (bitki)	Animalia (hayvan)
Phylum	Charophyta (Charophyta)	Mollusca (Yumuşakçalar)
Class	Charophyceae (Charophyceae)	Gastropoda (Karından bacaklılar)
Order	Charales (Charales)	Aplysiida (Aplysiida)
Family	Characeae	Akeridae
Genus	Tolypella	Akera
Species	Tolypella glomerata	Akera bullata

Conservation Status

Clustered Stonewort

VU — Vulnerable

common bubble snail

LC — Least Concern

Physical Characteristics

Attribute	Clustered Stonewort	common bubble snail
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Clustered Stonewort

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Sweden. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

common bubble snail

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Denmark, Norway, Portugal, and Sweden.

Clustered Stonewort

Tolypella glomerata, the clustered stonewort, is a charophyte alga in the family Characeae, found in calcareous, nutrient-poor freshwater habitats including lakes, ponds, ditches, and slow-flowing water in northwestern and northern Europe. Charophytes are macroscopic green algae with a distinctive whorl-like arrangement of branches and a complex, plant-like structure that distinguishes them from other algae. T. glomerata is encrusted with calcium carbonate deposits (hence 'stonewort'), giving it a pale, grey-green appearance and rough texture. The species colonizes clear, low-nutrient water over fine sediment or gravel substrates where competition from vascular plants is reduced by nutrient limitation. It is listed as Vulnerable by the IUCN, reflecting significant declines driven by eutrophication (nutrient enrichment from agriculture and sewage), which promotes the growth of vascular plants and phytoplankton that shade out stoneworts. Drainage, water abstraction, and peat cutting also threaten its habitats. Charophyte diversity has declined substantially across lowland Europe and North America over the past century, with many species becoming locally extinct from sites they once colonized.

common bubble snail

The common bubble snail (<em>Akera bullata</em>) is a marine gastropod mollusc found in the coastal waters of Denmark, Norway, Portugal, and Sweden. This species typically inhabits terrestrial and aquatic environments including forests and freshwater-adjacent marine areas, often occurring in shallow subtidal and intertidal zones of temperate European seas. It is classified as Least Concern on the IUCN Red List. As a member of the family Akeridae, the common bubble snail is characterized by its thin, fragile shell and its ability to swim briefly by flapping its large, wing-like parapodia. The species often forages on algae and detritus in sandy and muddy seafloor habitats, particularly in sheltered bays and estuaries. The common bubble snail typically aggregates in large numbers during the spawning season, producing gelatinous egg masses. Biological traits of this species remain poorly documented in the scientific literature.