Diatoms

Definition

Diatoms are a group of microalgae characterized by their unique silica cell walls known as frustules. These single-celled organisms are essential to aquatic ecosystems, playing a significant role in biomineralization, as they extract dissolved silica from their environment to create intricate and beautiful structures. Their ability to photosynthesize makes them key contributors to the global carbon cycle, influencing both marine and freshwater habitats.

5 Must Know Facts For Your Next Test

1. Diatoms are among the most abundant organisms on Earth, accounting for approximately 20% of the global carbon fixation.
2. They reproduce asexually through a process called binary fission, leading to rapid population growth under favorable conditions.
3. Diatoms have a diverse range of shapes and sizes, with over 100,000 known species varying in their frustule patterns.
4. Their frustules contribute significantly to the geological record, forming deposits like diatomaceous earth, which is used in various industrial applications.
5. Diatoms play a crucial role in aquatic food webs, serving as primary producers that support various organisms, including zooplankton and fish.

Review Questions

• How do diatoms contribute to biomineralization in aquatic ecosystems?
  • Diatoms contribute to biomineralization by extracting dissolved silica from their surroundings to form their unique silica-based cell walls, known as frustules. This process not only provides structure and protection for the diatoms but also influences the overall silica cycle in aquatic ecosystems. The presence of diatoms can affect the availability of nutrients and contribute to the geochemical dynamics within marine and freshwater environments.
• Discuss the ecological importance of diatoms in relation to carbon fixation and primary production.
  • Diatoms play a critical role in carbon fixation as they are responsible for about 20% of the Earth's total primary production. Through photosynthesis, they convert sunlight into energy while absorbing carbon dioxide from the water, which contributes to reducing atmospheric CO2 levels. This ability positions them as key players in mitigating climate change and supporting marine food webs by providing energy and nutrients to higher trophic levels.
• Evaluate the impact of environmental changes on diatom populations and their subsequent effects on aquatic ecosystems.
  • Environmental changes such as pollution, climate change, and habitat destruction can significantly impact diatom populations by altering nutrient availability, water temperature, and light conditions. A decline in diatom abundance can disrupt primary production in aquatic ecosystems, leading to reduced food resources for herbivorous species. Furthermore, changes in diatom diversity can affect biogeochemical cycles, potentially destabilizing entire aquatic food webs and altering ecosystem health.

Related terms

Frustule: The hard and porous outer wall of diatoms, composed primarily of silica, which provides structural support and protection.

Silica: A mineral composed of silicon dioxide (SiO2), which diatoms use to construct their frustules and is a key component in biomineralization.

Photosynthesis: The process by which diatoms and other plants convert light energy into chemical energy, producing oxygen and organic compounds from carbon dioxide and water.