Fan-shaped diatom
Meridion circulare
Meridion circulare is a unicellular diatom that forms distinctive fan-shaped or circular colonies. Individual cells are wedge-shaped and connected at their narrow ends by mucilage. It preferentially colonizes cold, oxygen-rich running waters, springs, and streams. As an autotrophic organism, it makes a significant contribution to primary production in aquatic ecosystems.
Details
Oxygen production
High, contributes significantly to oxygen saturation in streams.
Habitat function
Colonizes stones and aquatic plants (periphyton) and provides structure to microhabitats.
Nutrient uptake
Absorbs dissolved silicates, nitrates, and phosphates for biomass production.
Food source for
Food source for insect larvae (e.g., mayflies) and small crustaceans.
Human use
Used in limnology for biological water quality monitoring.
Ecology
Ecological role
Important primary producer; base of the food chain in running waters.
Natural predators
Protozoa, rotifers, and benthic invertebrates (grazers).
Competitor species
Other diatoms such as Diatoma vulgare or Gomphonema species.
Ecosystem service
Oxygen production through photosynthesis and fixation of carbon dioxide.
Threats
Eutrophication of water bodies, chemical pollution, and excessive warming of running waters.
Scientific profile
Protection & threats
Main threats
Eutrophication (nutrient input from agriculture), water warming due to climate change, structural degradation of springs and headwaters.