Slender Diatom
Nitzschia gracilis
The slender Nitzschia (Nitzschia gracilis) is a widespread species of diatom primarily found in freshwater habitats. It is characterized by its extremely narrow and elongated cell shape, resembling fine needles. As part of both phytoplankton and phytobenthos, it plays a crucial role in the nutrient cycling of aquatic ecosystems. Its cell wall consists of a complex, two-part silica frustule that exhibits characteristic patterns under microscopic examination.
Details
Oxygen production
Produces oxygen as a byproduct of photosynthesis, contributing to water aeration.
Habitat function
Provides a food source for primary consumers in the pelagic zone and on underwater surfaces.
Nutrient uptake
Absorbs nitrates, phosphates, and silicates from the water, thereby regulating the nutrient balance.
Food source for
Zooplankton, protozoa, and various aquatic invertebrates.
Ecology
Ecological role
Important primary producer; base of the food chain for zooplankton and benthic microorganisms.
Natural predators
Zooplankton (e.g., Daphnia), ciliates, small crustaceans, and insect larvae.
Competitor species
Other diatom species and green algae competing for light and nutrients.
Ecosystem service
Oxygen production through photosynthesis and contribution to carbon fixation in inland waters.
Threats
Water pollution by herbicides, extreme acidification, and silicate deficiency.
Scientific profile
Profile
Distinguishing features
The species is characterized by extremely slender valves (width only 2-4 µm). The fibulae (keel puncta) are clearly visible at 12-18 per 10 µm, while the transapical striae are extremely fine (approx. 40-50 per 10 µm) and barely resolvable by light microscopy. The raphe is eccentric within a keel.
Reproduction
Asexual reproduction via vegetative cell division, where each daughter cell inherits one valve and synthesizes the smaller one; sexual reproduction via auxospore formation to restore cell size.
Protection & threats
Status not on standard scale
Main threats
Excessive eutrophication (hypertrophication), chemical pollutant input, and massive herbicide contamination in agricultural landscapes.
Conservation measures
Maintenance and restoration of natural water dynamics; reduction of diffuse nutrient inputs from agriculture.