Monactinus Biwae

monactinus biwae

Monactinus Biwae is a beautiful, microscopic green alga renowned for its striking star-like geometric symmetry. Operating as a free-floating colonial organism, it consists of a single-layered disc of cells precisely arranged in concentric rings. This microalga plays a vital role in freshwater food webs, serving as a primary producer that converts solar energy into organic matter while oxygenating its aquatic environment.

Habitat: Inhabits the open waters of freshwater lakes, reservoirs, and slow-moving rivers, thriving as a component of floating phytoplankton.

Appearance

Under a microscope, Monactinus Biwae resembles a green, wheel-like structure or gear. It forms flat, disc-shaped colonies (coenobia) typically consisting of 8, 16, 32, or 64 cells. The inner cells are polygonal and fit tightly together, while each outer cell is characterized by a single, prominent, outward-pointing horn or spine, giving the entire colony a starburst appearance. The cells are rich in green chlorophyll, which gives them a vibrant, grass-green coloration.

KingdomPlantaePhylumChlorophytaClassChlorophyceaeOrderSphaeroplealesFamilyHydrodictyaceaeGenusMonactinus

Photo: Michele JonesCC BY 4.0 · iNaturalistView original ↗

Monactinus Biwae

Interesting facts

It is named after Lake Biwa in Japan, the country's largest freshwater lake, where it was historically studied in detail.

Its outer cells feature a single horn-like projection, which distinguishes the genus Monactinus from its close relative Pediastrum, which typically has two.

The number of cells in a colony is determined at birth and does not increase; individual cells simply grow larger as the colony matures.

Special abilities

The flat, single-layered disc structure maximizes surface area exposure to sunlight, optimizing the efficiency of its photosynthetic process.

During reproduction, motile zoospores gather inside a temporary vesicle and spontaneously align into a perfect geometric colony before developing cell walls.

The cell wall contains robust, decay-resistant biopolymers that protect the colony from sudden osmotic shifts and physical damage.

Measurements & details

Length: 0 cm
Clutch Size: 8-64

Diet & Feeding

As a photosynthetic organism, it manufactures its own food using sunlight, carbon dioxide, and dissolved inorganic nutrients from the water.

Primary Foods

Sunlight
Carbon dioxide
Dissolved nitrates
Dissolved phosphates

Foraging Method

Photosynthesis

Ecological connections

Eaten by

Common Water Flea

Daphnia pulex

Serves as a vital source of nutrition for filter-feeding zooplankton.

Competitor

Microcystis

Microcystis aeruginosa

Competes for dissolved phosphorus and nitrogen in freshwater lakes.

Traits

No trait badges are assigned for this object yet.

Also known as

No aliases listed yet.

Collections

Collections for this object will appear here as more themes are added.

Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Monactinus Biwae?

Start with the whole plant, then compare leaf arrangement, leaf edges, stems and any flowers or fruit. Opposite leaves grow in pairs; alternate leaves come one at a time along the stem. These details tell you far more together than a single green leaf does. Plant Identifier: upload a photo and compare the visible details.

How long is Monactinus Biwae?

0 cm

What does Monactinus Biwae eat?

As a photosynthetic organism, it manufactures its own food using sunlight, carbon dioxide, and dissolved inorganic nutrients from the water.

Where is Monactinus Biwae usually found?

Inhabits the open waters of freshwater lakes, reservoirs, and slow-moving rivers, thriving as a component of floating phytoplankton.

How does Monactinus Biwae hunt?

Photosynthesis

How many eggs does Monactinus Biwae lay?

8-64