Effects of Unsafe Levels

pHpH• Safe levels: Safe levels: Between 6.5 and 9

• Sources: Sources: decaying matter causes acidic conditions

• Effects of Unsafe Effects of Unsafe Levels: Levels: too high or too low can kill organisms; not all organisms can live in 6.5 to 9 range

NitratesNitrates• Safe levels: Safe levels: Less than 1 mg/L for aquatic

life & less than 10 mg/L for drinking • Sources: Sources: fertilizers, animal wastes, &

decomposing matter• Effects of Unsafe Levels: Effects of Unsafe Levels: can cause

excessive plant and algae growth in a process called eutrophicationeutrophication; this process harms or kills animals and can kill plants due to overcrowding

PhosphatesPhosphates• Safe levels: Safe levels: 0.01 to 0.03 mg/L• Sources: Sources: phosphate containing rocks and

solids; animal waste, fertilizers, pesticides, cleaning products, and industrial processes

• Effects of Unsafe Levels: Effects of Unsafe Levels: can also cause excessive plant growth in a process called eutrophication (click for video description.)(click for video description.)

Cause and effects… Cause and effects… … … of changes in temperature, dissolved of changes in temperature, dissolved oxygen, turbidity, and bio-indicators oxygen, turbidity, and bio-indicators

TemperatureTemperature• Different species

have different temperature preferences

• Warm water dissolves more solids

• Warm water dissolves less dissolved gases • Very warm water may not contain enough DO for life to exist

Oxygen enters water through diffusion with air and photosynthesis of aquatic plants

When dissolved oxygen levels decline, sensitive animals may move away, weaken, or die

Dissolved OxygenDissolved Oxygen

TurbidityThe more suspended solids in the water the less transparent it is

High turbidity can lead to increased water temperatures, low dissolved oxygen, and physical impairment of organisms

Bio-indicatorsBio-indicators Good water quality is indicated by a variety of macroinvertebrates

Poor water quality is indicated by a few of one type of macroinvertebrates in one place

BIOINDICATOR DIAGRAM:

The white ring of environmental variables includes factors that may be directly altered by disturbance or stress. These alterations may then affect individual organisms, populations, or the community as a whole. The outermost colored ring represents individual organisms, the middle colored ring represents populations of those organisms, and the innermost colored ring represents the community in which all three species coexist. Disturbance or stress may negatively affect energy resources (e.g., food, light), biotic interactions (e.g., competition), and the physical or chemical (e.g., nutrients) environment. These environmental changes may increase or decrease growth and reproduction of an organism, consequently impacting the size and productivity of the population and interactions with other species in the community.

The Domino EffectThe Domino EffectYou notice a pond in a golf course

downhill from the grass is covered in green algae.

Cause: Too much nitrates/phosphates cause overgrowth of algae which causes…

Effect: Increased turbidity which causes… Increase temperature which causes… Decreased dissolved oxygen which

causes… Death of organisms living in pond &

eutrophication

The Domino EffectThe Domino EffectYou notice that the water in your fish tank is

very cloudy and your favorite goldfish looks like it is struggling to live.

Cause: Increase turbidity causes…

Effect: Increase temperature which causes… Decreased dissolved oxygen which causes… Death of goldfish

Acid OceansWhat are the effects of an unsafe pH level, and rising temperatures in the ocean?

Watch Discovery video- American Museum of Natural History Science Bulletins: Acid Oceans