Rhodovulum: A genus of facultatively or obligately anaerobic marine phototrophic bacteria, in the family RHODOBACTERACEAE.Phototrophic Processes: Processes by which phototrophic organisms use sunlight as their primary energy source. Contrasts with chemotrophic processes which do not depend on light and function in deriving energy from exogenous chemical sources. Photoautotrophy (or photolithotrophy) is the ability to use sunlight as energy to fix inorganic nutrients to be used for other organic requirements. Photoautotrophs include all GREEN PLANTS; GREEN ALGAE; CYANOBACTERIA; and green and PURPLE SULFUR BACTERIA. Photoheterotrophs or photoorganotrophs require a supply of organic nutrients for their organic requirements but use sunlight as their primary energy source; examples include certain PURPLE NONSULFUR BACTERIA. Depending on environmental conditions some organisms can switch between different nutritional modes (AUTOTROPHY; HETEROTROPHY; chemotrophy; or phototrophy) to utilize different sources to meet their nutrients and energy requirements.Rhodobacter: A genus of gram-negative bacteria widely distributed in fresh water as well as marine and hypersaline habitats.Heterotrophic Processes: The processes by which organisms utilize organic substances as their nutrient sources. Contrasts with AUTOTROPHIC PROCESSES which make use of simple inorganic substances as the nutrient supply source. Heterotrophs can be either chemoheterotrophs (or chemoorganotrophs) which also require organic substances such as glucose for their primary metabolic energy requirements, or photoheterotrophs (or photoorganotrophs) which derive their primary energy requirements from light. Depending on environmental conditions some organisms can switch between different nutritional modes (AUTOTROPHY; heterotrophy; chemotrophy; or PHOTOTROPHY) to utilize different sources to meet their nutrients and energy requirements.Thiosulfates: Inorganic salts of thiosulfuric acid possessing the general formula R2S2O3.North SeaSulfur Compounds: Inorganic or organic compounds that contain sulfur as an integral part of the molecule.Bacteriochlorophyll A: A specific bacteriochlorophyll that is similar in structure to chlorophyll a.Asia, Central: The geographical area of Asia comprising KAZAKHSTAN; KYRGYZSTAN; TAJIKISTAN; TURKMENISTAN; and UZBEKISTAN. The desert region of Kara Kum (Qara Qum) is largely in Turkmenistan and the desert region of Kyzyl Kum (Kizil Kum or Qizil Qum), is in Uzbekistan and Kazakhstan. (From Webster's New Geographical Dictionary, 1988, p233, 590, 636)Proteobacteria: A phylum of bacteria consisting of the purple bacteria and their relatives which form a branch of the eubacterial tree. This group of predominantly gram-negative bacteria is classified based on homology of equivalent nucleotide sequences of 16S ribosomal RNA or by hybridization of ribosomal RNA or DNA with 16S and 23S ribosomal RNA.Organic Chemicals: A broad class of substances containing carbon and its derivatives. Many of these chemicals will frequently contain hydrogen with or without oxygen, nitrogen, sulfur, phosphorus, and other elements. They exist in either carbon chain or carbon ring form.Chemoautotrophic Growth: Growth of organisms using AUTOTROPHIC PROCESSES for obtaining nutrients and chemotrophic processes for obtaining a primary energy supply. Chemotrophic processes are involved in deriving a primary energy supply from exogenous chemical sources. Chemotrophic autotrophs (chemoautotrophs) generally use inorganic chemicals as energy sources and as such are called chemolithoautotrophs. Most chemoautotrophs live in hostile environments, such as deep sea vents. They are mostly BACTERIA and ARCHAEA, and are the primary producers for those ecosystems.Bacterial Physiological Phenomena: Physiological processes and properties of BACTERIA.Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.Sulfides: Chemical groups containing the covalent sulfur bonds -S-. The sulfur atom can be bound to inorganic or organic moieties.Rhodospirillaceae: A family of phototrophic bacteria, in the order Rhodospirillales, isolated from stagnant water and mud.RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.Genes, rRNA: Genes, found in both prokaryotes and eukaryotes, which are transcribed to produce the RNA which is incorporated into RIBOSOMES. Prokaryotic rRNA genes are usually found in OPERONS dispersed throughout the GENOME, whereas eukaryotic rRNA genes are clustered, multicistronic transcriptional units.DNA, Ribosomal: DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.Rhodobacteraceae: A family in the order Rhodobacterales, class ALPHAPROTEOBACTERIA.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Pigments, Biological: Any normal or abnormal coloring matter in PLANTS; ANIMALS or micro-organisms.Carotenoids: The general name for a group of fat-soluble pigments found in green, yellow, and leafy vegetables, and yellow fruits. They are aliphatic hydrocarbons consisting of a polyisoprene backbone.Photosynthetic Reaction Center Complex Proteins: Protein complexes that take part in the process of PHOTOSYNTHESIS. They are located within the THYLAKOID MEMBRANES of plant CHLOROPLASTS and a variety of structures in more primitive organisms. There are two major complexes involved in the photosynthetic process called PHOTOSYSTEM I and PHOTOSYSTEM II.Seawater: The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.RNA, Bacterial: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.