Chironomidae: A family of nonbiting midges, in the order DIPTERA. Salivary glands of the genus Chironomus are used in studies of cellular genetics and biochemistry.Eichhornia: A plant genus of the family PONTEDERIACEAE that is used as a biological filter for treating wastewater.Rivers: Large natural streams of FRESH WATER formed by converging tributaries and which empty into a body of water (lake or ocean).Bromelia: A plant genus of the family BROMELIACEAE. Members contain karatasin and balansain (ENDOPEPTIDASES) and BROMELAINS.Eryngium: A plant genus of the family APIACEAE. Members contain SAPONINS.Larva: Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.Diptera: An order of the class Insecta. Wings, when present, number two and distinguish Diptera from other so-called flies, while the halteres, or reduced hindwings, separate Diptera from other insects with one pair of wings. The order includes the families Calliphoridae, Oestridae, Phoridae, SARCOPHAGIDAE, Scatophagidae, Sciaridae, SIMULIIDAE, Tabanidae, Therevidae, Trypetidae, CERATOPOGONIDAE; CHIRONOMIDAE; CULICIDAE; DROSOPHILIDAE; GLOSSINIDAE; MUSCIDAE; TEPHRITIDAE; and PSYCHODIDAE. The larval form of Diptera species are called maggots (see LARVA).Invertebrates: Animals that have no spinal column.Population Density: Number of individuals in a population relative to space.BrazilBiodiversity: The variety of all native living organisms and their various forms and interrelationships.Fresh Water: Water containing no significant amounts of salts, such as water from RIVERS and LAKES.Fungi: A kingdom of eukaryotic, heterotrophic organisms that live parasitically as saprobes, including MUSHROOMS; YEASTS; smuts, molds, etc. They reproduce either sexually or asexually, and have life cycles that range from simple to complex. Filamentous fungi, commonly known as molds, refer to those that grow as multicellular colonies.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)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.Population Dynamics: The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.