Lakes: Inland bodies of still or slowly moving FRESH WATER or salt water, larger than a pond, and supplied by RIVERS and streams.Great Lakes Region: The geographic area of the Great Lakes in general and when the specific state or states are not indicated. It usually includes Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin.Fresh Water: Water containing no significant amounts of salts, such as water from RIVERS and LAKES.Eutrophication: The enrichment of a terrestrial or aquatic ECOSYSTEM by the addition of nutrients, especially nitrogen and phosphorus, that results in a superabundant growth of plants, ALGAE, or other primary producers. It can be a natural process or result from human activity such as agriculture runoff or sewage pollution. In aquatic ecosystems, an increase in the algae population is termed an algal bloom.Cichlids: Common name for perch-like fish of the family Cichlidae, belonging to the suborder Labroidei, order PERCIFORMES.Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.Zooplankton: Minute free-floating animal organisms which live in practically all natural waters.Phytoplankton: Free-floating minute organisms that are photosynthetic. The term is non-taxonomic and refers to a lifestyle (energy utilization and motility), rather than a particular type of organism. Most, but not all, are unicellular algae. Important groups include DIATOMS; DINOFLAGELLATES; CYANOBACTERIA; CHLOROPHYTA; HAPTOPHYTA; CRYPTOMONADS; and silicoflagellates.Geologic Sediments: A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)Ecosystem: A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)Africa, Eastern: The geographical area of Africa comprising BURUNDI; DJIBOUTI; ETHIOPIA; KENYA; RWANDA; SOMALIA; SUDAN; TANZANIA; and UGANDA.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.Perches: A common name for fish of the family Percidae, belonging to the suborder Percoidei, order PERCIFORMES.Microcystis: A form-genus of CYANOBACTERIA in the order Chroococcales. Many species are planktonic and possess gas vacuoles.Plankton: Community of tiny aquatic PLANTS and ANIMALS, and photosynthetic BACTERIA, that are either free-floating or suspended in the water, with little or no power of locomotion. They are divided into PHYTOPLANKTON and ZOOPLANKTON.Antarctic Regions: The continent lying around the South Pole and the southern waters of the Atlantic, Pacific, and Indian Oceans. It includes the Falkland Islands Dependencies. (From Webster's New Geographical Dictionary, 1988, p55)DNA, Ribosomal: DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Fishes: A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.Microcystins: Cyclic heptapeptides found in MICROCYSTIS and other CYANOBACTERIA. Hepatotoxic and carcinogenic effects have been noted. They are sometimes called cyanotoxins, which should not be confused with chemicals containing a cyano group (CN) which are toxic.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Biodiversity: The variety of all native living organisms and their various forms and interrelationships.Environmental Monitoring: The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.Sodium Chloride: A ubiquitous sodium salt that is commonly used to season food.Cladocera: A suborder of CRUSTACEA, order Diplostraca, comprising the water fleas. They are benthic filter feeders that consume PHYTOPLANKTON. The body is laterally compressed and enclosed in a bivalved carapace, from which the head extends.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.Water Pollution: Contamination of bodies of water (such as LAKES; RIVERS; SEAS; and GROUNDWATER.)Water Pollutants: Substances or organisms which pollute the water or bodies of water. Use for water pollutants in general or those for which there is no specific heading.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Water Pollution, Chemical: Adverse effect upon bodies of water (LAKES; RIVERS; seas; groundwater etc.) caused by CHEMICAL WATER POLLUTANTS.Eichhornia: A plant genus of the family PONTEDERIACEAE that is used as a biological filter for treating wastewater.Daphnia: A diverse genus of minute freshwater CRUSTACEA, of the suborder CLADOCERA. They are a major food source for both young and adult freshwater fish.Alligators and Crocodiles: Large, long-tailed reptiles, including caimans, of the order Loricata.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Halobacteriaceae: A family of extremely halophilic archaea found in environments with high salt concentrations, such as salt lakes, evaporated brines, or salted fish. Halobacteriaceae are either obligate aerobes or facultative anaerobes and are divided into at least twenty-six genera including: HALOARCULA; HALOBACTERIUM; HALOCOCCUS; HALOFERAX; HALORUBRUM; NATRONOBACTERIUM; and NATRONOCOCCUS.Salmonidae: A family of anadromous fish comprising SALMON; TROUT; whitefish; and graylings. They are the most important food and game fishes. Their habitat is the northern Atlantic and Pacific, both marine and inland, and the Great Lakes. (Nelson: Fishes of the World, 1976, p97)Salinity: Degree of saltiness, which is largely the OSMOLAR CONCENTRATION of SODIUM CHLORIDE plus any other SALTS present. It is an ecological factor of considerable importance, influencing the types of organisms that live in an ENVIRONMENT.China: A country spanning from central Asia to the Pacific Ocean.Eukaryota: One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.Water Movements: The flow of water in enviromental bodies of water such as rivers, oceans, water supplies, aquariums, etc. It includes currents, tides, and waves.Rivers: Large natural streams of FRESH WATER formed by converging tributaries and which empty into a body of water (lake or ocean).Humic Substances: Organic matter in a state of advanced decay, after passing through the stages of COMPOST and PEAT and before becoming lignite (COAL). It is composed of a heterogenous mixture of compounds including phenolic radicals and acids that polymerize and are not easily separated nor analyzed. (E.A. Ghabbour & G. Davies, eds. Humic Substances, 2001).Smegmamorpha: Group of fish under the superorder Acanthopterygii, separate from the PERCIFORMES, which includes swamp eels, mullets, sticklebacks, seahorses, spiny eels, rainbowfishes, and KILLIFISHES. The name is derived from the six taxa which comprise the group. (From http://www.nanfa.org/articles/Elassoma/elassoma.htm, 8/4/2000)DNA, Archaeal: Deoxyribonucleic acid that makes up the genetic material of archaea.Wetlands: Environments or habitats at the interface between truly terrestrial ecosystems and truly aquatic systems making them different from each yet highly dependent on both. Adaptations to low soil oxygen characterize many wetland species.Geography: The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)Biomass: Total mass of all the organisms of a given type and/or in a given area. (From Concise Dictionary of Biology, 1990) It includes the yield of vegetative mass produced from any given crop.Genetic Speciation: The splitting of an ancestral species into daughter species that coexist in time (King, Dictionary of Genetics, 6th ed). Causal factors may include geographic isolation, HABITAT geometry, migration, REPRODUCTIVE ISOLATION, random GENETIC DRIFT and MUTATION.Base Composition: The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.Cyanobacteria: A phylum of oxygenic photosynthetic bacteria comprised of unicellular to multicellular bacteria possessing CHLOROPHYLL a and carrying out oxygenic PHOTOSYNTHESIS. Cyanobacteria are the only known organisms capable of fixing both CARBON DIOXIDE (in the presence of light) and NITROGEN. Cell morphology can include nitrogen-fixing heterocysts and/or resting cells called akinetes. Formerly called blue-green algae, cyanobacteria were traditionally treated as ALGAE.Phosphorus: A non-metal element that has the atomic symbol P, atomic number 15, and atomic weight 31. It is an essential element that takes part in a broad variety of biochemical reactions.UtahCold Climate: A climate characterized by COLD TEMPERATURE for a majority of the time during the year.Actinobacteria: Class of BACTERIA with diverse morphological properties. Strains of Actinobacteria show greater than 80% 16S rDNA/rRNA sequence similarity among each other and also the presence of certain signature nucleotides. (Stackebrandt E. et al, Int. J. Syst. Bacteriol. (1997) 47:479-491)Freshwater Biology: The study of life and ECOLOGIC SYSTEMS in bodies of FRESHWATER.Bacteroidetes: A phylum of bacteria comprised of three classes: Bacteroides, Flavobacteria, and Sphingobacteria.