Aquatic Ecosystems

pH- how acidic or basic the water is.• If the water is really acidic it will

sustain all aquatic plant and animal life that neutral water would not.

Factors that affect pH• Bedrock• Acid rain• Carbon Dioxide etc…

• Dissolved Oxygen-The concentration of oxygen dissolved in water, where saturation is the maximum amount of oxygen that can theoretically be dissolved in water at a given altitude and temperature.

• As dissolved oxygen levels in water drop below 5.0 mg/l, aquatic life is put under stress. The lower the concentration, the greater the stress. Oxygen levels that remain below 1-2 mg/l for a few hours can result in large fish kills

Alkalinity• Basically it is the ability of a solution to

neutralize acids.

To maintain a fairly constant pH in a water body, ahigher alkalinity is preferable. High alkalinity

meansthat the body of water has the ability to neutralizeacidic pollution from rainfall or basic inputs fromwastewater.

• If the water flow, water temperature, water turbidity , and surface tension are too high in an aquatic ecosystem, then aquatic life will die off.

• When water flows down a slope, it tends to gather in small depressions on the surface along the way. This concentration of moving water stimulates the process of erosion. As the water erodes rock and other material in the depression, it forms a channel. The stream channel is the landform, not the water carried in it.

• A stream's speed determines its ability to erode, transport, and deposit sediment. Sediment is rock debris such as clay, silt, sand, gravel, or even larger material. A fast-moving stream carries more sediment and larger material than a slow-moving one. A stream that is turbulent can also lift and carry more rocks and sediment than one that flows gently. Turbulence is due to the friction caused by rocks and steps in the stream's channel.

How water influences water flow, channel shape and habitat types

The Water Cycle

•Surface runoff can carry pollutants into the water which can kill aquatic organisms.•Acid rain causes lakes and streams become more acidic when the water itself and its surrounding soil cannot buffer the acid rain enough to neutralize it.