Cladophora, Genus, spp., Multiple species,

Genus
Multiple species

blanketweed

Cladophoraceae Worldwide (fresh, brackish, marine)

Overview

Cladophora is a genus of branching filamentous green algae in the family Cladophoraceae, found in fresh, brackish, and marine waters worldwide. The plants are built from chains of large, multinucleate cells joined end to end into coarse, wiry, much-branched filaments that form green tufts, mats, or floating masses. In flowing water the filaments anchor to rock, wood, or shells and stream out as long green threads; in still or enriched water they can form thick, cottony blankets. The texture is harsher and more wiry than soft green algae like Spirogyra, and the branching, cell structure, and attached habit help separate it. Cladophora grows quickly where light and nutrients are high, and several species form heavy nuisance blooms in lakes, rivers, and on shores enriched by run-off, sometimes washing up in rotting drifts. The genus tolerates a wide range of light, temperature, and water chemistry. Reproduction is by swimming spores and gametes and by simple fragmentation of the filaments. In the Great Lakes and elsewhere, blooms tied to nutrient pollution and invasive mussels have made some species a recurring problem. The coarse, branched, attached filaments mark out the genus.

Native Range

Cladophora occurs worldwide in fresh, brackish, and marine waters, attached to rock, wood, shells, and other surfaces in rivers, lakes, tide pools, and shallow seas, and sometimes floating free. Several species are widespread and form nuisance blooms in nutrient-rich waters.

Suggested Uses

Ball-forming Cladophora, sold as marimo moss balls, is kept in aquariums as a low-care ornamental. The genus is studied as an indicator of nutrient pollution and as a cause of nuisance blooms in lakes and rivers. Beach-cast Cladophora is sometimes used as fertiliser.

How to Identify

Identify by the coarse, wiry, much-branched green filaments built from large cells joined end to end, attached to rock or other surfaces or forming floating mats. The harsh, branched texture separates Cladophora from soft, unbranched green algae such as Spirogyra. Branching pattern and cell features confirm the genus under a microscope.

Appearance

Colors

Foliage Colors

green

Bloom Information

Cladophora does not flower. It reproduces by swimming spores and gametes and by simple fragmentation, with broken filaments growing into new plants. Growth is fastest in warm, well-lit, nutrient-rich water, when nuisance blooms can develop.

Growing Conditions

Water & Climate

Water Needs

High

Care & Maintenance

Care Guide

Cladophora grows in fresh, brackish, or marine water on hard surfaces, tolerating a wide range of light, temperature, and chemistry, and growing fastest where nutrients and light are high. In aquaria most species are treated as a nuisance to be reduced by cutting nutrients, improving flow, and manual removal, though the ornamental ball-forming species are kept on purpose. Nutrient pollution and strong light encourage heavy growth. Low nutrients and grazing reduce it.