Home >> Science & Nature >> Nature

Facts on Abiotic Fresh Water Biomes

Freshwater biomes are characterized by the low salt content of the waters and are predominantly found around lakes, ponds and rivers. The abiotic factors are the non-living aspects of the biome that affect the living organisms, such as plants and animals. Favorable abiotic conditions are needed to maintain a biome and allow the living organisms to thrive and reproduce.

Sunlight
- Sunlight is an important abiotic factor in any biome, but it affects each in an individual way. In a freshwater biome the aspect of the sun affects the absorption of light. During the day when the sun is at it height, more light is absorbed by the water. At night the reverse is true. The presence of cloud cover affects the intensity of sunlight able to reach the water and decreases the length of time the water has to absorb sunlight. Some freshwater plant species rely on a specific amount of sunlight daily for photosynthesis, so variations in sunlight affect which plants are able to survive.
Oxygen
- Whether water moves, or is still, affects the biome's organisms. It can particularly affect the amount of oxygen available to living organisms. The oxygen concentration in water determines which species can survive in it as animals rely on oxygen for aerobic respiration. Three key factors affect water's oxygen concentration: the size of the surface area exposed to air, the circulation of water by convection currents plus oxygen produced by plant respiration. As temperature has an effect on oxygen levels, the depth of the water also has a bearing on oxygen levels.
Temperature
- Living organisms thrive at specific optimum temperatures. Within lakes, for example, there may be a huge difference between the temperature close to the surface of the lake and that at the bottom. This varies with the season. During summer the temperature on the surface may be 22 degrees C, while at the bottom it's only 4 degrees C. During winter, the bottom of the lake may still be 4 degrees C, while at the top it's at freezing point. Winds help regulate temperatures in a lake by mixing water from the different layers and creating a balance.
Precipitation
- The water cycle plays an important role in maintaining freshwater biomes. The biomes, particularly the larger ones, also have an effect on climate. Lakes need rainfall to replenish water lost through evaporation. This moisture, or water vapor, is collected in the air and forms clouds. Once over land, the collected moisture falls as rain, or precipitation. This precipitation runs back into the lakes. Melting snow is another source of water that keeps lakes topped up.

Nature