7. Microbiology - Water Flashcards
- the biological activity of an aquatic ecosystem depends on ____A______? give 2 examples
- these ____A_____ serve as a ______ source for chemoheterotrophs (bacteria, protozoa, zooplankton), fish, other aquatic organisms
the activities and net numbers of phytoplankton depend on (3)
- depends on primary producers! (photoautotrophs, phytoplankton) –> can do carbon fixation! ie algae and cyanobacteria!
*cyanobacteria = very good for ecosystem bc source of food for other microorgs BUT if grow uncontrollably = bad - primary produces serve as food source for chemoheterotrophs…
- temperature
- light received
- availability of specific limiting nutrients like Nitrogen and Phosphorus (in water) –> typically this that limits growth of microorgs (vs temp and light)
what is the photic zone?
- open ocean vs coastal waters
PHOTIC ZONE
- zone/depth of water colum where light can penetrate!
- in clear water, can penetrate to a maximum depth of 300m
- best for metabolic diversity
*microorgs must be able to harvest light that reaches them (accessory pigments)
OPEAN OCEAN:
- when water is clear: light can go until 200-300m –> red on goes a few meters, blue can go very deep, that’s why ocean we see is blue
COASTAL WATERS:
- close to the coast: lots of particles: rain from land carry particles to sea
- best case scenario: 50m deep of photic zone
MARINE ENVIRONMENT
- high/low salinity? means that which orgs can live there?
- ____% of ocean is deeper than 1000m –> deep sea = ________ ZONE
- at the ocean’s deepest (_____ km below surface) –> pressure is about ____ atm
- below 100m, temperature is constant at ___-____°C –> what type of orgs can survive there?
- high salinity (3%) –> halotolerant or halophile
- 75% –> deep sea = PELAGIC zone
- 11km below surface –> 1100 atm (bc 1 atm/10 m ish)
- 2-3°C –> psychrophiles (fridge temps)
OPEN OCEAN
- in the pelagic zone, primary productivity is very high/low due to WHAT
- SO, open ocean is _______trophic
- temperatures are hotter/cooler and more/less constant than in area closer to shore
- in some regions, what can happen –> promotes/decreases productivity
- measure concentration of what to measure productivity?
- very LOW due to lack of inorganic nutrients (nitrogen, phosphorus, iron) that are required by phytoplankton
- OLIGOTROPHIC (ocean desert)
- cooler and more constant than shore
- wind and ocean currents cause an upwelling of water from ocean floor bringing nutrients to surface/water column and promoting productivity
*ie gulf stream and labrador current near nova scotia and newfoundland –> sediments at -200m are brought back to surface! = more microorgs = more fish! - concentration of chlorophyll! marker of photosynthesis
OPEN OCEAN:
- bulk of primary productivity comes from _________________ –> describe. example?
- general adaptations seen in pelagic (open ocean) microorgs: (2)
- trichodesmium –> does 3 things/adaptations
- from prochlorophytes –> tiny phototrophs phylogenetically related to cyanobacteria –> prochlorococcus (filaments!)
1) reduced size (high surface/volume ratio)
2) high affinity transport systems (ie ABC transport)
TRICHODESMIUM (type of prochlorophyte?)
- filamentous cyanobacteria
- contains phycobilins: to harvest as much light as possible
- nitrogen fixation
COASTAL WATER:
- primary producers: (2)
- productivity is usually higher/lower due to WHAT
- so, coastal water is _______trophic
- can cause _____ _________
- what is a limiting nutrient
- higher/lower level of primary productivity supports WHAT
- algae, cyanobacteria
- higher due to influx of nutrients from rivers and other polluted water sources (ie agricultural runoff (cause excess nitrogen and phosphorus) + sewages)
*very shallow: mix of water will bring back sediments into the water column/photic zone = lots of nutrients - EUTROPHIC! = very rich in nutrients
- can cause red tides (algal bloom, dinoflagellates, neurotoxins)
- nitrogen is a limiting nutrient
- higher level of primary productivity supports a higher concentration of zooplankton and aquatic animals
DEEP SEA:
- WHAT zone?
- depth: between ____ and ____m
- temp?
- which type of orgs (like chemo/photo hetero/auto troph) degrade organic/inorganic matter that fall from WHAT?
BELOW 1000m:
- what is very scarce –> _______trophic
- light?
- what types of microorgs are there?
is there life at > 10 000m?
DEEP SEA:
- pelagic zone
- 300 to 1000m, still some O2 though
- 2-3°C –> psychrophiles
- chemoheterotrophs degrade organic matter that falls from the photic zones (ie a whale that dies)
BELOW 1000:
- organic carbon is very scarce –> oligotrophic
- no light
- very few microorg (psychrophilic + barophilic or barotolerant)
yes! we don’t understand it at all though
HYDROTHERMAL VENT
- source of (4)
- do microorgs and animals live around it? around what?
- tube worms: symbiosis with what? explain
*hydrothermal vents = exceptions ish –> very deep but:
- source of heat, nutrients, electron donor and electron acceptors
- communities of microorgs (microbial mats) and animals live around the CHIMNEY
TUBE WORMS: symbiosis with sulfur oxidizing chemoautotrophs
- tube worms trap and transport nutrients to the bacterial symbionts, which supplies the worm with organic material
*bacteria supplies worm with organic material
FRESHWATER ENVIRONMENT:
- highly variable/constant –> why?
- microbial populations depend on (3)
- 2 types ish: good or bad mising/aeration
- highly variable! isolated system compared to ocean bc they are ISOLATED!
1) availability of nutrients –> limited by the availability of nitrogen and phosphorus!
2) availability of light
3) availability of oxygen
1) lakes: POOR mixing/aeration: no waves, no current, no mixing down water column
2) rivers: GOOD mixing/aeration –> more O2 going in water
*but some rivers/lakes are oligotrophic: very few nutrients, very clear, can see bottom, not many microorgs
OLIGOTROPHIC LAKES
- which 2 substances are limiting?
- primary production is high/low, availability of organic matter is high/low
- growth of aerobic/anaerobic _____________ is limited by WHAT
- oxygen concentration remains high/low
- rate of oxygen dissolution is higher/lower than consumption rate
- lake remains aerobic/anaerobic even at depth, and organic matter is _____________ completely
- oxygen depleted/saturated
- clear/dark water
- N and P!
- low and low!
- aerobic chemoheterotrophs is limited by nutrient supply!
- O2 concentrations remain high!
- rate of O2 dissolution is HIGHER than consumption rate!
- remains aerobic even at depth and org matter is degraded completely
- oxygen SATURATED (ie good for fish)
- clear water –> deep penetration of light
smells good, super clean
*as soon as there’s some organic matter (ie rabbit pees in it), all the organic carbon is fully oxidized by chemotrophs
EUTROPHIC LAKE
- primary production is high/low, availability of organic matter is high/low
- rapid growth of _______________, rapid depletion of what?
- low/high concentrations of O2
- rate of oxygen dissolution is higher/lower than consumption rate
- aerobic/anaerobic zones created
- deep/poor light penetration
- health risk? (2)
- high and high!
- rapid growth of chemoheterotrophs, rapid DEPLETION of dissolved oxygen
- LOW O2 concentrations
- rate of O2 dissolution is lower than rate of consumption!
- ANAEROBIC zones are created –> so microorgs do anaerobic resp + fermentation –> produce bad smells
- POOR light penetration
- pathogens + bloom of cyanobacteria/algae (secrete toxins)
EUTROPHIC LAKE:
- bottom sediments are aerobic/anaerobic and contain organic/inorganic matter (ex) which support growth of (3)
- anaerobic/aerobic photosynthesis uses WHAT as electron donor and produces WHAT, which is used by WHO
- excessive production of WHAT and production of WHAT from _____________ can give water a bad odor
- what (2) may kill fish and other aerobic organisms?
- ANAEROBIC + contain ORGANIC matter (ie dead primary producers, etc.) which support growth of denitrifiers, methanogens and sulfate reducers (produce sulfide! H2S)
- ANAEROBIC photosynthesis uses H2S as e- donor and produces sulfate which is used by SULFATE REDUCERS
- excessive production of H2S and the production of organic acids from fermentation can give water bad odor
- lack of O2 and/or presence of H2S may kill fish and other aerobic organisms
LAKES IN TEMPERATE CLIMATES:
- anaerobic/aerobic zones may develop as a result of WHAT –> lakes become __________ stratified
- describe the 4 stages
- when is there mixing?
anaerobic zones may develop as a result of summer stratification! lakes become thermally stratified
1. WINTER: ice on top, 4°C water = most dense –> go to the bottom, crust of earth heats up bottom water ish to 4°C
2. SPRING TURNOVER as ice melts, ice goes down water column and warmer water goes up = mixing!
3. SUMMER STRATIFICATION: as air temp increases, surface water is warmed = formation of a warm upper layer (epilimnion) –> much less dense than 4° water + O2 = aerobic respiration VS bottom layer (hypolimnion) = more dense, anaerobic
*epilimnion and hypolimnion are separated from each other by a zone of rapid temperature change: thermocline
4. FALL TURNOVER: top layer cools down to the same temp as bottom layer –> mixes stuff up: mixing brings back nutrients up water column + rings O2 down water column
*mixing only in the spring and fall! brings nutrients back up the water column
RIVERS:
- good or bad aeration and mixing?
- ensures that WHAT is degraded effectively?
- is there fermentation and H2S production?
- excess organic matter may still result in ___________ with consequences similar to those seen in ___________ lake
- good!!!
- ensures that organic matter, within limits, is degraded effectively! –> more tolerant to organic matter bc mixing = less accumulation of toxins
- no fermentation or H2S production –> more diffusion of O2
- may still result in anaerobiosis with consequences similar to those seen in eutrophic lakes
*more resistant to atrophication (?)
POLLUTION
- define pollution of freshwater
- major source? –>describe that source
- ________ & ________ organisms reduce/oxidize organic matter using WHAT
- what is BOD –> used as a measure of what?
- deliberate discharge of effluents into a waterway
- SEWAGE! rich in organic matter (fecal, urine, soap, food) and contins a large number of organisms (may contain pathogens!)
- aerobic and facultative organisms OXIDIZE org matter using dissolved oxygen
- Biochemical oxygen demand –> used as a measure of the extent of pollution by organic matter + measure of metabolic activity/amount of O2 consumed by orgs
ie high BOD = lots of chemoorganotrophs that burn nutrients through aerobic respiration
what happens to
a) O2
b) bacteria, organic C and BOD
c) algae and cyanobacteria
d) NO3-
e) NH4+ and PO4^3-
as distance downstream of sewage increases
- normal water:
- normal O2
- low b,c,d,e - input: sewage, other waste-waters
- O2 starts to decrease, and reaches a very low level as b) peaks
- bacteria, organic C, BOD increases! reaches peak!
- c) decreases a little
- d) and e) increase - further downstream:
- increase in algae and cyanobacteria
decrease in b), d) and e) bc MORE DILUTION with time and distance
- bc b, d and e decrease, O2 goes back to normal levels
BIOFILM
- define
- usually produced by a single or a mix of species?
- extracellular matrix composed of (3)
- cells inside biofilm are resistant?
- biofilms are found where (4)
- Biofilm: microbial cells embedded inside an extracellular matrix
- Usually produced by a mixed population of species. –> multispecies!
- composed of proteins, polysaccharides, DNA (holds everything together)
- Cells inside the biofilm are more resistant to stresses than planktonic (free-living) cells –> ECM acts a bit like a capsule! protects against predation, desinfectant, mechanical stress
- water systems (natural and man-made) (ie clogging of water pipe, biofouling of a ship full)
- on wet surfaces (ie shower, pink stuff)
- growing on medical devices (can be source of infection = bad)
- can grow on surface of river! = microbial mat in river
WATER-BORNE PATHOGENS
- most of these pathogens grow WHERE and how are they transmitted to humans?
- sources of infection (2) –> increasing or decrease throughout the years?
- grow in intestinal tract of animals! – transmission is mediated by fecal contamination of water supplies/bodies –> if humans drink that water = can acquire pathogen = bad
*fecal - oral route
1) potable water: drinking and food prep (ie wash veg)
- decreasing throughout the years –> better at making water safe
2) recreational water: swimming, water skiing, canoeing…
- increasing throughout years –> bc more water being contaminated by sewage/waste
give examples of water-borne BACTERIAL pathogens (5) and VIRUS (2)
- Salmonella spp. (other than typhi): salmonellosis, gastroenteritis –> localized diarrhea
- Salmonella typhi: typhoid fever in humans, healthy carriers –> NOT localized –> systemic infection = more lethal!
- Vibrio cholerae: cholera, severe diarrhea (enterotoxin) –> can lose 20L per day
- Shigella spp.: shigellosis; bacterial dysentery (bloody diarrhea, inflammation of the intestinal mucosa) –> GI infection
- Campylobacter spp.: gastroenteritis, most common cause of gastroenteritis in
Canada. - Enterovirus: poliovirus, norovirus, rotavirus (children) –> very contagious, cruise ships!
- Hepatitis A virus.
give examples of water-born pathogenic PROTOZOA/protists (3) + describe
- Entamoeba histolytica: amoebic dysentery. –> amoeba –> GI infection
GIARDIA LAMBLIA:
- giardiasis (backpacker’s disease/beaver fever)
- chronic diarrhea, often associated with drinking water in wilderness areas (beavers and muskrats are frequent carriers – source of contamination of streams/pees in stream)
CRYPTOSPORIDIUM PARVUM:
- acute diarrhea in healthy individuals –> self-limiting
- chronic diarrhea & major problem in immunocompromised individuals (AIDS, chemo), no reliable treatment
- Present in 90% sewage samples, 75% river waters and 28% of drinking waters –> prevalence is high + hard to ged rid of
G. lamblia and C. parvum can form ______A_____ that are resistant to WHAT
- C. parvum ____A_____ are NOT effectively removed by what?
- CYSTS! resistant to several disinfectants, including chlorine!
- C. parvum cysts are VERY small –> not effectively removed by filtration process in water plants
WATER-QUALITY CONTROL
- goal?
- is it possible to check for all pathogens? –> what to do instead?
- 2 indicators
- presence of the 2nd one, especially ________, indicates WHAT
- absence of both indicators ensures that the water quality is good?
- goal = make sure water is safe for drinking!
- Impossible to check for all pathogens –> bc most water-borne pathogens are associated with fecal material –> Test the water for organisms that are present in large numbers in feces – use these organisms as indicators of fecal pollution – if these organisms are present, there is a chance that the water may also contain pathogens.
1) COLIFORMS:
- facultative aerobic, Gram-negative, non spore-forming, rod-shaped bacteria that can ferment lactose with gas formation within 48 hours at 35°C –> not super specific
*ferment lactose –> MacConkey agar
- Includes a variety of bacteria not all of intestinal origin.
- indicates general contamination
2) FECAL COLIFORMS
- coliforms derived from the intestines of warm-blooded animals (can grow at 44.5°C, thermotolerant)
- ie E. coli
- indicates contamination from fecal matter
- presence of fecal coliforms, especially E. coli, indicate FECAL CONTAMINATION and that the water is unsafe for human consumption.
- absence of fecal coliforms/coliforms does NOT ensure good water quality (cysts are more resistant than fecal coliforms).
what are 2 ways to test for coliforms? explain
1) MEMBRANE FILTRATION
- test coliforms and fecal coliforms
- test large volume of water (100mL) –> pour sample in flask but has to pass through membrane filter –> put membrane filter on culture medium (probs smtg that can identify lactose fermentation) –> check growth of colony + color of colonies
- have to concentrate sample bc need to detect 1 bacteria/100 mL
- faster and easier than MPN
2) MOST PROBABLY NUMBER (MPB)
- test for coliforms: samples are added to lactose broth. If gas production is detected (change color (?)), test is positive = safe (?)
- Use statistical tables to estimate the MPN of coliforms in the original sample –> look at number of large wel; and # of small well –> where they interact = MPN number
- Presumptive tests, further tests needed for confirmation.
*can also use PCR to detect DNA –> but doesnt mean bacteria is alive
what are the 4 aims of water treatment?
- extent of treatment needed depends on what?
*death rates of typhoid fever in USA decreased after WHAT began?
- remove pathogens –> not trying to sterilize!
- improve clarity of water
- remove compounds that give bad smell or taste
- soften the water/adjust mineral quantity
*overall goal: make water potable - depends on the quality of the source of water
*after chlorination began
why is New York city water disgusting even though it comes from really good natural sources?
bc distributing pipes are really old and bad
explain the steps of drinking water treatment (3 big steps + explain)
- COAGULATION, FLOCCULATION, SEDIMENTATIONS
- Water is left to stand in a reservoir (sedimentation basin) –> Allow large particle (sands, dead fish) to settle
- chemicals are added to the water to neutralize dirt = coagulation
- Flocculation: flocculating chemical (coagulant/floculins –> binds to things in suspension = fall to bottom) is added –> Water is transferred to a flocculation basin and allowed to settle for ~6h.
- SEDIMENTATION: As the flocs (flaky precipitates) form, they trap fine particles (clay, bacteria, viruses, protists). Some organic chemicals are also absorbed by the flocs
- ~80% of bacteria, color and particulates have been removed –> 80% = not even a 10-fold reduction - FILTRATION
- The water is filtered through sand to remove remaining particles, even more bacteria and any remaining G. lamblia cysts.
- after this stage, 98-99.5% of the bacteria have been removed (but not cryptosporidium spores) –> much cleaner, most pathogens are eliminated
- Filter is backflushed regularly to prevent clogging. - DESINFECTION
- Chlorine is very reactive in water + cheap + need low dose –> it forms strong oxidizing agents –> Kills remaining microorganisms (some are resistant) + Neutralizes most of the chemicals that give water a bad smell/taste.
* OR use Ozone: more effective that chlorine (kills G. lamblia and C. parvum cysts) but very short half-life. - water is now stored + safe for human consumption.
what is residual chlorine? why?
why is ozone sometimes used for desinfection?
what are the thresholds for coliforms and fecal coliforms in montreal?
what happened in the Walkerton tragedy?
Residual chlorine: amount of chlorine that remains in the water that left the treatment plant
- Desired/required to protect the distribution system –> oxidizes pathogens/microorgs that are in the pipes! helps remove biofilm in distribution pipes
Ozone: bc more effective than chlorine –> kills G. lamblia and C. parvum cysts
- used for certain sources that are more susceptible to cyst contamination
Quality control (Montreal): < 10 coliforms/100ml; <1 fecal coliform/100ml
massive E.coli outbreak bc messed up filtration system –> didn’t have good tests bc of budget cuts + water from farms
- half of population got sick
is water purification a new concept?
no! Tikal in Mexico used it > 2000 years ago
- romans also used it
what are the 2 aims of wastewater/sewage treatment?
- how many treatment steps ish? describe general steps
- reduce BOD (by removing and destroying organic matter, N and P) –> to prevent negative effect of BOD into a river/body of water –> decrease eutrophication
- destroy pathogens
- PRIMARY treatment: wastewater –> screening –> sedimentation –> into solid (sludge) and liquid
- SECONDARY treatment
- anaerobic digestion of sludge + drying/incineration/use as fertilizer
- aerobic oxidation of liquid + desinfection
PRIMARY TREATMENT of wastewater/sewage:
- sedimentation tanks: ___-____% of suspended solids settle
- WHAT can be added?
- produces WHAT (2)
- reduces BOD of wastewater to ___-____% and bacteria by ___-____%
- what happens after? (2)
- 40-70% settle
- FLOCCULATING chemical can be added to further separate
- produces PRIMARY SLUDGE at the bottom (dried and incinerated OR secondary treatment) + LIQUID
- BOD: decrease to 25-40%
- bacteria: decrease by 25-75%
- wastewaters can be discharged to waterways OR go through secondary treatment (use microorgs to reduce BOD and concentration of bacteria further)
*in mtl: only do primary treatment: dump in St-Laurent river after
SECONDARY treatment of wastewater/sewage –> LIQUID
- overall principle?
- 2 types + explain
*BOD and bacteria reduced by how much?
- use microbes already present in liquid –> give them right condition so they can consume organic C in water + P and N –> grow and form particles that we can collect
TRICKLING FILTER:
- liquid from primary treatment is sprayed over a bed of rock or plastic honeycomb
- microorganisms form biofilms, coating the surface and oxidize the organic matter present in the sewage
- BOD reduced by 80-95%, bacteria by 90-95%.
ACTIVATED SLUDGE:
- air is blown through the liquid from primary treatment
- Slime-forming bacteria grow and clump together to form flocs (activated sludge) that oxidize the organic matter
- Then, the material passes to a settling tank, sludge is removed for disposal or secondary treatment (or can be inoculated again in aeration tank to accelerate process
- BOD reduced by 85-95%, bacteria by 90-98%.
SECONDARY treatment of wastewater/sewage –> SLUDGE
- ________ and _______ sludge, containing (2) is subjected to WHAT under aerobic/anaerobic conditions –> 3 steps ish
- WHAT is produced? –> can be used for what?
- BOD reduced by ___%
- what happens to material that remains? (2)
- primary and secondary sludge –> contain cellulose and other organic compounds –> subjected to microbial digestion under ANAEROBIC conditions
*complex polymers hydrolyzed by microbial enzymes –> forms monomers (sugars, FA, aa) –> fermented into acetate and H2 and CO2 –> methanogenesis –> forms CH4 - CH4 can be used to power the treatment plant
- BOD reduced by 90%
- material that remains (sludge) is incinerated or buried
TERTIARY treatment of wastewater/sewage
- what does it do?
- may involve any or a combination of (4)
- produces potable water?
- Further reduces the BOD, bacteria and the concentrations of N and P.
1) Biological treatment (pump water into a pond –> where you grow algae to further reduce N and P)
2) Flocculation
3) Filtration
4) Chlorination or ozonation - The final liquid effluent that come from wastewater treatment plant that uses primary, secondary and tertiary treatments MAY be suitable for drinking (if coliforms and fecal coliforms below limits).
what happens if you don’t live close to a water treatment facility? use what instead? explain
- BOD reduced by ___%
- effluent flows to a _________ _________ + details
- minimal treatment of sewage –> use SEPTIC tank!
- Within the tank: settling of the material + minimal sludge digestion –> requires periodic emptying.
- BOD of effluent reduced by 60%.
Effluent flows to a LEACHING field (tile field):
- Still contains > 10,000 coliforms/ml.
- Reduce amount of water in the tank.
- Soils act as a filter and organisms decompose organic matter –> Care has to be taken to prevent contamination of groundwater and nearby waterways
*might get grass that grows really well on top of the sewage pipes
