he pH of the water. The amount of sunlight received also plays a large role in the Columbia River Basins ecosystem. The light from the sun provides light for the primary producers, plants. There are many factors that can affect the intensity and length of time that the ecosystem is exposed to sunlight. The first is the angle at which light strikes the surface of the water. During the day when the sun is high in the sky, more light can be absorbed into the water due to the directness of the light. At sunset, light strikes the water surface more acutely, and less water is absorbed. The aspect of the sun during times of the day will vary depending on the time of the year. The cloud cover of an area will inevitably affect intensity and length of time that light strikes the water of a freshwater ecosystem. Species of plants rely on a critical period of time where they receive light for photosynthesis. The 4 seasons in an ecosystem are very different, and this is because less light and heat is available from the sun in winter and vice versa for summer. In the Columbia River Basin this year the high temperature was 98F in June, and the lowest was 24F in November. These varying conditions will affect which organisms are suited to them. Altitude will also affect the aspect of which sunlight hits the freshwater ecosystem, therefore playing a part on which organisms will occupy it.Rainfall and temperature play another large role in the Columbia River Basin. In the year 1999-2000 this area received 33.25 inches of rainfall, that is 2.37 inches bellow normal, and the ninth driest year since 1941. This lack of rain greatly effects the surrounding organisms. The areas that received less than 30 cm of rain per year in the Columbia River Basin are seeing great effect on wildlife. Populations of both grassland and shrub-steppe species such as the sage grouse, Columbian sharp-tailed grouse, sagebrush vole, upland sandpiper, grasshopper sparrow, and pro...
