Diatoms

Definition

Diatoms are a group of microalgae characterized by their unique silica cell walls, which have intricate and beautiful patterns. These single-celled organisms are a major component of phytoplankton in marine and freshwater ecosystems, playing a crucial role in primary production. They convert sunlight into energy through photosynthesis and contribute significantly to global oxygen production and carbon cycling.

5 Must Know Facts For Your Next Test

1. Diatoms account for about 20% of the global oxygen supply, making them vital for sustaining life on Earth.
2. They reproduce rapidly through asexual reproduction, doubling their population in just a few hours under optimal conditions.
3. Diatoms can be found in a wide range of habitats, from oceans and lakes to moist soils, demonstrating their ecological versatility.
4. Their silica cell walls accumulate on the ocean floor over time, forming diatomaceous earth, which is used in various industries including filtration and as a natural pesticide.
5. Different species of diatoms are indicators of environmental changes and water quality, making them important for ecological monitoring.

Review Questions

• How do diatoms contribute to primary production in aquatic ecosystems?
  • Diatoms play a significant role in primary production by converting sunlight into chemical energy through photosynthesis. As primary producers, they form the foundation of the aquatic food web, providing energy for various organisms such as zooplankton and fish. Their ability to thrive in diverse aquatic environments allows them to sustain high levels of productivity, impacting overall ecosystem health.
• Discuss the ecological importance of diatoms in relation to carbon cycling and oxygen production.
  • Diatoms are critical for carbon cycling as they absorb carbon dioxide during photosynthesis and convert it into organic matter. When they die, their silica shells sink to the ocean floor, sequestering carbon away from the atmosphere. This process not only helps regulate atmospheric CO2 levels but also contributes to oxygen production; diatoms generate around 20% of the Earth's oxygen through photosynthesis.
• Evaluate the impact of environmental changes on diatom populations and how this affects broader ecosystems.
  • Environmental changes such as temperature fluctuations, nutrient availability, and water quality can significantly impact diatom populations. A decline or shift in diatom species can disrupt primary production, leading to cascading effects throughout the food web. For example, if nutrient levels decrease, it may result in reduced diatom growth, which could subsequently diminish food sources for herbivores like zooplankton, ultimately affecting higher trophic levels including fish and marine mammals.

Related terms

Phytoplankton: Microscopic organisms that live in aquatic environments and perform photosynthesis, forming the base of the aquatic food web.

Silica: A natural compound made of silicon and oxygen that diatoms use to construct their intricate cell walls.

Primary Production: The process by which autotrophs, like diatoms, convert light energy into chemical energy stored in organic compounds.