Effects of Pollution on Biodiversity

How do we know when water is polluted?

-Some forms are easy to detect (e.g. oil spills), but most are not.
-Two ways of testing water:
1. Chemical indicators – measuring chemical concentrations of water
2. Biological indicators – measuring how much life the body of water is supporting.
Types of water pollution (General):
-seep into the ground as runoff from watering or rain
-seep into the ground as runoff from watering or rain
-not poisonous by nature, but cause health problems in large quantities.
-can lead to the creation of dead zones: areas where the bottom water (the water at the sea floor) are anoxic, meaning that they have a low concentration of dissolved oxygen.
-this is caused by an excess of nutrients that cause phytoplankton (algae) growth which deplete the oxygen supply.
-“creeping dead zones” – dead zones that are increasing in size
-frequently found at the mouths of major rivers
-excess fertilizer runs off farms and makes its way into waterways and eventually the river mouths. This fertilizer serves as extra food for the phytoplankton.
Map of Dead Zones:
Dead Zones Map
Dead Zones Map

-Oil spills and runoff:
-oil floats on the water’s surface, cutting off oxygen to the sea life below.
(Animal covered in Oil)
-biggest danger is oil tanker accidents: example – Exxon Valdez spilled 11 million gallons of oil.
-many marine habitats are regularly exposed to oil pollution even without the oil tanker spills, especially those near developed areas. Oil pollution in water comes from street runoff, industrial liquid wastes, and intentional discharge from ships flushing their oil tanks.
-Ocean littering problems:
-entangles wildlife (especially Seals)
(Plastic six pack ring tangled on a duck)
-litter can look like a food source (Example: Seabirds have been found with plastic in stomachs)
-smothers plants
-means for small organisms to invade non-native areas
-contributes to toxic water pollution
-Some scientists once thought it was safe to dump garbage into the oceans, believing that the oceans were large enough to take it in.
-Summer of 1988: massive amount of debris washed up on the Atlantic seaboard, forcing 803 beaches to close.
-1994: hundreds of dead dolphins washed up on the Mediterranean shores, infected by a virus from water pollution.
-Laws against ocean dumping: Title I of the Marine Protection, Research, and Sanctuaries Act of 1972, often referred to as the Ocean Dumping Act (http://www.eoearth.org/article/Ocean_Dumping_Act,_United_States), which has been amended many times making the regulations more strict.
-marine litter will stay in the environment for anytime from two weeks (cardboard box) to 450 years (plastic bottles)
-can cause brain damage and other problems
-can be passed to humans by eating animals with mercury poisoning
-it is carried to rivers and streams by rainwater from coal-burning power plants, garbage incinerators, and metal smelters.
-most rapidly growing form of water pollution.

[Click on link to see larger version of image.]



What is the government doing to try to prevent water pollution?

-Federal Water Pollution Control Amendments of 1972-(Clean Water Act)
goal: restore and maintain quality of American waters
1. Prohibits dumping of Toxic Pollutants and proper disposal of household chemicals
2. Federal government funding for publicly owned waste treatment plants
3. States required to begin planning for water pollution control
4. Established research facilities to research options to end water pollution
5. Require EPA (enviromental Protection Agency) to publish a list of the toxic pollutants
-Clean Water Act (1977)-(Revisions)
- gave states even more authority
-EPA extended list of toxic pollutants
-Water Quality Act of 1987 (1987)
-applicable to storm water discharges

Where is water pollution most prevalent?


Which organisms are impacted by water pollution OR how is biodiversity affected?

  • All aquatic species are affected by water pollution and many amphibians absorb the chemicals, fertilizers, and various other pollutants.
  • Each type of water pollution can effect each type of aquatic organism. All species are at risk of absorbing or ingesting contaminants and ingesting needles, forceps, and many other forms of solid waste that are commonly found in all bodies of water.
  • In 1994 hundreds of dead dolphins washed up on Mediterranean beaches. They all died from a virus linked to water pollution.
  • In 2002, The Environmental Protection Agency's (EPA) National Fish and Wildlife Contamination Program reported that Mercury was the cause of 2,140 fish and wildlife consumption advisories. FACT: (If a human consumes an aquatic species that lived in mecury infested waters, that human is at large risk of getting mercury poisoning, which can be deadly.)
  • One growing problem relating directly to water pollution is biomagnification. Biomagnification ocurrs when a predator consumes a species that is contaminated with pesticides from the waters, and in turn its tissues absorb all of those pesticides from its prey.
  • This has been known to ocurr especially among bird higher in the food chain.
Ex. bald eagles and peregrine falcons
  • Biomagnification proves that not only are the species in polluted waters affected by contaminants, but their pollution has the great potential of spreading to other land organisms fairly easily.