Shield-shaped diatom
Cocconeis placentula
This diatom is characterized by a flat, elliptical shield shape and belongs to the group of monoraphid diatoms. The cells typically live firmly attached to substrates such as stones or macrophytes, maintaining close contact with the surface. Their silica frustule is highly symmetrical and features fine pore structures that are visible under a microscope.
Details
Oxygen production
Significant contribution to oxygen enrichment in the benthic zone.
Habitat function
Forms dense biofilms that serve as settlement space for other microorganisms.
Nutrient uptake
Extensive uptake of nitrates, phosphates, and silicates for frustule construction.
Food source for
Grazers of the macrozoobenthos such as Gastropoda and Ephemeroptera larvae.
Human use
Used in paleolimnology as an indicator to reconstruct historical water levels and nutrient conditions.
Ecology
Ecological role
Important primary producer in the periphyton, producing oxygen and forming the basis of aquatic food webs.
Natural predators
Protozoa, rotifers, snails, and mayfly larvae.
Competitor species
Other periphytic algae such as Achnanthidium minutissimum or Gomphonema species.
Ecosystem service
Contribution to the self-purification of water bodies and fixation of atmospheric carbon.
Threats
Excessive eutrophication, herbicide input, and strong mechanical stress on substrates.
Scientific profile
Protection & threats
Main threats
Input of herbicides (e.g., atrazine), extreme eutrophication (light limitation due to plankton blooms), and acidification of water bodies.