| Abstract from DBPedia | Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats can be classified by different factors, including temperature, light penetration, nutrients, and vegetation. There are three basic types of freshwater ecosystems: Lentic (slow moving water, including pools, ponds, and lakes), lotic (faster moving water, for example streams and rivers) and wetlands (areas where the soil is saturated or inundated for at least part of the time). Freshwater ecosystems contain 41% of the world's known fish species. Freshwater ecosystems have undergone substantial transformations over time, which has impacted various characteristics of the ecosystems. Original attempts to understand and monitor freshwater ecosystems were spurred on by threats to human health (for example cholera outbreaks due to sewage contamination). Early monitoring focused on chemical indicators, then bacteria, and finally algae, fungi and protozoa. A new type of monitoring involves quantifying differing groups of organisms (macroinvertebrates, macrophytes and fish) and measuring the stream conditions associated with them. Threats to freshwater biodiversity include overexploitation, water pollution, flow modification, destruction or degradation of habitat, and invasion by exotic species. Climate change is putting further pressure on these ecosystems because water temperatures have already increased by about 1°C, and there have been significant declines in ice coverage which have caused subsequent ecosystem stresses.陸水生物学（りくすいせいぶつがく、英: Freshwater biology）とは、陸水を生息域とする生物の生活や生態系を扱う、生物学の一分野である。湖、川、池に生息する動物、植物、微生物を研究対象としている。陸水の生息域は、温度、光、植生により分類される。 (Source: http://dbpedia.org/resource/Freshwater_ecosystem) |
