Chlorobium is a genus of green sulfur bacteria that are known for their ability to perform photosynthesis using light energy. These bacteria contain chlorosomes, which are specialized structures that help capture light, allowing them to thrive in low-light environments, such as deep water or sediments. They primarily use hydrogen sulfide as an electron donor, converting it into sulfur granules. These bacteria play a crucial role in the ecosystem by participating in the sulfur cycle. They contribute to the breakdown of organic matter and help recycle nutrients in aquatic environments. Chlorobium species are often studied for their unique metabolic processes and potential applications in biotechnology.