Which of the following microorganisms is known for its photosynthetic capabilities and unique cellular structures?

Diatoms are a group of unique algae that are recognized for their remarkable photosynthetic capabilities. They possess specialized cellular structures known as frustules, which are made of silica and provide them with a distinctive and intricate appearance. This structure not only aids in their buoyancy but also serves protective functions.

Diatoms are crucial players in aquatic ecosystems, contributing significantly to primary productivity by converting sunlight into chemical energy through photosynthesis. Their ability to harness solar energy makes them essential to the food web, supporting both phytoplankton and the larger ecosystem by producing oxygen and organic material.

In contrast, the other options refer to categories of microorganisms that do not possess these photosynthetic traits or unique structural features. Anaerobes are organisms that thrive in environments without oxygen, halophiles are adapted to high salt concentrations, and alkaliphiles survive in alkaline environments. None of these categories inherently include the photosynthetic capabilities or the distinct cellular structures that define diatoms.