Biosphere Flashcards
Ecotoxicology
the study of the ecological consequences of polluting the environment with various substances and radiation released by human activity.
Contaminant
any type of substance or radiation that is likely to cause harm to one or more ecosystems.
Types of contaminants:
a. The concentration (higher concentration=more toxic)
b. Type of organism it comes in contact with (contaminants are toxic to some organisms)
c. The length of exposure (longer exposed: risk of toxicity higher)
Toxicity threshold
the level of concentration above which a contaminant causes one or more harmful effects in an organism.
Lethal doses
LD50. Used to compare toxicity of contaminants and indicates the amount of contaminant necessary, in a single dose, to cause the death of an organism.
Bioaccumulation
the gradual accumulation of substances, such as pesticides or other chemicals, in ONE organism.
Biomagnification/bio amplification:
the rise or increase in the contaminated substances caused by the intoxicating environment. (Up the food chain).
Biodegradation
(organic breaks down organic). It is the breaking down of organic matter into inorganic matter by microorganisms.
Bioremediation
(bacteria eats toxins). It is a biotechnology for cleaning up a polluted site, using microorganisms that decompose the contaminants.
Phytoremediation
(plants absorb toxins but store them inside). It is a biotechnology that uses plants or algae to eliminate contaminants from a site.
Photosynthesis in carbon cycle
plants use solar energy to capture carbon dioxide found in the atmosphere or water.
Ingestion in CC
to take carbon to grow, animals eat plants or other animals.
Respiration in CC
carbon ingested returns to atmosphere as Carbon Dioxide.
Forest fires in CC
release immense amount of carbon into the atmosphere
Shells and skeletons in CC
CO2 in water reacts with molecules to form calcium to become calcium carbonate to form shells and skeletons. This also helps marine organisms.
Carbonate rock in CC
shells and skeletons calcium carbonate form carbonate rock, which is subject to tectonic movement and can go back to surface.
Volcanic eruptions in CC
releases CO2 (carbon goes back to atmosphere)
Fossil fuels in CC
dead organisms fall to ocean floor and carbon changes into fossil fuels such as coal and oil. Takes hundreds of millions of years to process. (Releases CO2 into atmosphere.)
Nitrogen cycle 5 steps
a. Nitrogen Fixation in NC: certain bacteria in the soil or water take the nitrogen from the atmosphere and converts into ammonia. Some of the ammonia reacts with hydrogen to form ammonium.
b. Nitrification in NC: bacteria oxidize ammonium to form nitrites. Other bacteria oxidize nitrites into nitrates.
c. Nitrogen Absorption by Plants and Animals in NC: plants can draw ammonium and nitrates from soil or water. Vegetation represents the only source of nitrogen available to herbivorous animals, which meet their need by eating plants. Meanwhile, carnivores obtain their nitrogen by eating herbivores or other animals.
d. Decomposition of Waste in NC: certain bacteria and fungi break down the nitrogen-containing substances in plant and animals waste (urine, dead organisms). They produce ammonia, which dissolves and forms ammonium.
e. Denitrification in NC: certain bacteria convert nitrates into molecular nitrogen, which returns to the atmosphere.
Types of nitrogen
N, N2, NH3, NH4, NO2, NO3
Erosion in PC
naturally occurring phosphorus is mostly in rocks. The wind and the rain slowly wear away small amounts of phosphorus from the rock, usually in the form of phosphates.
Absorption by Living Organisms in PC:
plants can rapidly absorb the phosphates need for growth. Herbivores ingest phosphates by eating plants. Carnivores eat herbivores or other animals.
Decomposition of Waste in PC:
digested phosphates are returned to the soil. All animals eliminate phosphates in their feces and urine. Phosphates are also released when decomposers break down dead plants and animals.
Proliferation of Plankton and Sedimentation in PC:
phosphates from rocks or from animal and decomposed excretions make their way into the oceans. Some phosphates promote the growth of plankton (tiny marine organism that are the food of many larger life forms). Other phosphates sink to the bottom of the water and blend with the sediment. Very slowly, over millions of years, this mixture forms rock, returning to its original state.
