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Unit 3: Water Chemistry & Contaminants Exam Review. Exam Review. Organic vs. Inorganic Organic contains carbon Percentage of Freshwater 2.5% of the planet’s water is fresh water Common elements in organic molecules Carbon , hydrogen, and oxygen Hydrophilic “water loving” - PowerPoint PPT Presentation
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Unit 3: Water Chemistry & Contaminants Exam Review
Exam Review
• Organic vs. Inorganic– Organic contains carbon
• Percentage of Freshwater– 2.5% of the planet’s water is fresh water
• Common elements in organic molecules– Carbon, hydrogen, and oxygen
• Hydrophilic– “water loving”– A solute that will dissolve in water
• Hydrophobic– “water fearing”– A solute that will not dissolve or mix in water
Exam Review
• Alkalinity– The ability of a solution (body of water) to buffer
against a change in pH, specifically an increase in acidity
Exam Review
• Carbonate system
CO2(g)
CO2(aq)
H2O
H2CO3
H+
HCO3–
H+
CO32-
CaCO3(s)limestone
Ca2+
Carbonic Acid
Bicarbonate
Carbonate
pH
8 1064
Exam Review
• Diatoms – – Most common brown algae
• Euglena – – Has both animal & plant features, protist, prominent
flagella• Paramecium –
– Protist covered in cilia• Hydra –
– Animal with a tremendous regenerative ability• Amoeba –
– Protist that uses phagocytosis to consume other organisms
Exam Review
• Microbes & biomass– Microbes account for ~ 50% of all biomass on
Earth– They are ubiquitous on the surface and deep
within the earth• Species richness
– the total number (biodiversity) of different species present
• Species abundance– the total number of individuals in a sample
Exam Review
Exam Review
• Guilds– Metabolically related microbial populations– Microbial species richness and abundance is a
function of the kinds and amounts of nutrients available in a given habitat
• Niche– Job/role an organism plays within its environment
• Prime Niche– For each organism there exists at least one
niche in which that organism is most successful (thrive)
Exam Review
• Biofilms– Assemblages of bacterial cells adhered to a surface and
enclosed in an adhesive matrix excreted by the cells– The matrix is typically a mixture of polysaccharides
• Formation & purpose of biofilms– Self-defense
• Biofilms resist physical forces that sweep away unattached
cells, phagocytosis by immune system cells, and penetration of
toxins (e.g., antibiotics)
– Allows cells to remain in a favorable niche
– Allows bacterial cells to live in close association with one
another
Exam Review
Exam Review
• Biochemical Oxygen Demand (BOD)– The microbial oxygen-consuming capacity of
a body of water
• Prochlorococcus– > 40% of the biomass of marine phototrophs – ~50% of the net primary production– Most of the primary productivity in the open
oceans
Exam Review
• Psychrophilic/tolerant– cold-loving– Can survive the cold, but does not thrive
• Barophilic/tolerant– pressure-loving– Can survive the pressure, but does not thrive
Exam Review
• Change in ratios of archaea/bacteria through aquatic life zones
Exam Review
• Hydrothermal vent microbes– Chemolithotrophic prokaryotes that utilize
reduced inorganic materials emitting from the vents form endosymbiotic relationships with vent invertebrates such as vent tube worms
• Chemolithotrophic– Organisms that use inorganic matter (chemicals)
to create their own food (chemo-auto-trophs)
Nitrogen Cycle
Exam ReviewSimplified Nitrogen Cycle
NH4+
AmmoniumNO2
–
NitriteNO3
–
NitrateN2
Nitrogen
NitrosofyingBacteria
NitrifyingBacteria
DenitrifyingBacteria
Nitrogen Fixation
Nitrification Denitrification
Aerobic Anaerobic
Exam Review
• Bioremediation– Refers to the cleanup of oil, toxic chemicals, or
other pollutants from the environment by microorganisms
– Often a cost-effective and practical method for pollutant cleanup
• Xenobiotics –– chemically synthesized compounds that have never
occurred in nature (pesticides, herbicides, plastics).• Phytoremediation:
– Degrading a pollutant using sunlight/UV light– Downsides: only the surface is effected, and its slow
Exam Review
• Chemical Cocktails – – A mixture of chemicals that, when consumed
independently cause no/little harm, but when put together can have damaging, and rarely studied effects.
Exam Review
• Oxygen depleting contaminants– organic carbon + O2 + bacteria →
CO2 + H2O + more bacteria
– if oxygen is depleted in natural water, most aquatic life will die (Ex. fish kills)
• C:N:P molar ratio ideal for bacterial growth– 100:10:1– Phosphorous is often the limiting factor in
bacterial/algal growth
Exam Review
• Cyanotoxins - – Produced by algal blooms (blue-green algae) that
is toxic to humans and most animals. Under the right conditions, these blooms can reduce DO to the point that nearby organisms will asphyxiate.
• Effects of Total Dissolved Salts– Measured as Total Dissolved Solids (TDS)– High salt concentration can damage crops, reduce
soil’s permeability– In drinking water, recommended that
TDS < 500 mg/L
Exam Review
• Thermal pollution– Primarily cooling water from power plants and
other industries– ↑Temperature, ↓Dissolved oxygen– ↑Temperature, ↑bacterial growth, ↓DO
Exam Review
• Sources of Nitrates in water– Septic systems (on-site waste water disposal systems)– Runoff and leaching from agricultural land, residential
lawns and gardens (nitrogenous fertilizers)– Animal wastes (ranging from confined animal feeding
operations to horses in the pasture)• Methemoglobinemia
– In humans, nitrate (NO3-) is reduced to nitrite (NO2
-)– Nitrite binds with hemoglobin to form
methemoglobin, a substance that cannot bind and transport oxygen
– Methemoglobinemia effects children & preganacies
Exam Review
• Chlorine byproducts (DBPs)– Chlorine is a common disinfectant in drinking
water– Excellent oxidizing disinfectant– Inactivates most bacteria, viruses and certain
protozoa– Most DBPs are regulated based on their suspected
human carcinogenicity (known carcinogenicity to laboratory animals)
– Epidemiologic evidence that chlorine DBPs, primarily trihalomethanes, are related to adverse reproductive outcomes
Exam Review
• Trihalomethanes –– The most common DBP, highly volatile
• Viruses – – Smallest known microbial contaminant– Consist of a DNA/RNA filled capsid & enzymes
• Bacteria – – Simple internal organization, simple life cycle,
flagellated– Creates spores when stressed
Exam Review
• Protozoa – – Complex, single-celled organisms– Complex life cycle– Forms cysts/oocysts when stressed
• Helminths – – Parasitic worms ranging in size from microscopic
to over one meter in length– Very complex life cycles– Eggs serve as the environmentally resistant form
for helminths
Exam Review
• E. coli – – bacteria– Small number of US outbreaks & low number of cases. 3
to 5% fatal• Fomite –
– An inanimate object that houses pathogens
• Salmonella – – Bacteria– 12 to 30% mortality, low # of outbreaks, slightly higher #
of cases
Exam Review
• Vibrio cholera – – Bacteria– Low rate of infection within the US, but
responsible for a many-decade pandemic in Asia, Africa, and Latin America
• Giardia – – Protist– Larger number of US outbreaks higher rate of
infection than common infectious bacteria
Exam Review
• Cryptosporidium – – Protist– Small number of US outbreaks yielding an extremely
high rate of infection (421,473 cases)– 1-3% US, 5% Asia, 10% Africa infected at any given time
• Toxoplasmosis – – Oocysts are extremely resistant to common disinfectants– Cats are the definitive host for Toxo– Close to 25% of US population is infected– Life threatening to immuno-compromised individuals – Congenital infected children
Exam Review
• Platyhelminthes –– “flat” worms– Common examples: tape worms, flukes
• Ashelminthes – – “round” worms– Hookworms, ascaris, trichinella, etc
• Lung Fluke – • Hookworms –
– Extensive lifecycle: burrowing into skin, travelling through blood, lungs, stomach, then small intestine
– Shed 10,000 to 20,000 eggs per day– Can consume 0.2mL of blood per adult per day
Exam Review
• Trichinella –– “Biblical worm”– Most commonly found in swine muscle tissue & our first
example of nature/parasites/illnesses changing/shaping human culture
– Causes painful & aching muscles in infected humans • Ascaris –
– Large (25-45 cm) & most common infectious worm – Common where sanitation is poor & human feces is used
as fertilizer
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