Water Flashcards
The biological activity of an aquatic ecosystem ultimately depends on
The activities of the primary producers (phytoplankton)
What are primary producers in the ocean
Algae
Cyanobacteria
Phytoplankton serve as ___ for chemeheterotrophs
A food source
The activities and net number of phytoplankton and net numbers of phytoplankton depend on
- Temperature
- Light received
- Availability of specific limiting nutrients such as nitrogen and phosphorus
What is photic zone
In clear water, light will penetrate to a maximum of 300 m
How deep the light penetrates in coastal waters
50 m
Why in open ocean there is more light penetration than in the coastal region
Near the coat there is more particles dissolved
What organisms live in the ocean and why ( salt)
High salinity (3%)-> halotolerant or hylophylic
What is pelagic zone
the water column of the open ocean, and can be further divided into regions by depth. . It goes from the surface almost to the bottom
75 % of the ocean is deeper than
1000 m
What is the pressure at the deepest place in the ocean
1100 atm
What is the correlation between the depth and the pressure
every 10 m increasing by 1 atm
Below 100 m the temperature of the ocean is constant
2-3C
The open ocean is ___ (low nutrients)
oligotrophic
What is the outcome of the fact that the open ocean is oligotrophic
primary productivity is very low due to the lack of inorganic nutrients ( nitrogen, phosphorus, iron) that are required byp hytoplankton
Temperature of the water is ___ closer tot he shore
Warmer
What happens in some regions due to wind and ocean currents
Upwelling of water from the ocean floor bringing nutrients to the surface and promoting productivity
What is an indicator of the primary productivity
Chlorophyll
Chlorophyll concentration depends on
The season
bulk of primary productivity comes from
prochlorophytes
What are procholorophytes and there latin name
Tiny phototrophs phylogenetically related to the cyanobacteria.
Prochlorococcus
General adaptations seen in pelagic (open ocean) microorganisms
- Reduced size (high surface//volume ration)
- High affinity transport system
Who are trichodesmium and there characteristics
- Filamentous cyanobacteria
- Contains phycobilins ( help to capture light)
- Nitrogen fixation
As the primary productivity is higher in coastal water, how it can be called
Eutrophic
Where the influx of nutrients coming from to costal waters
Influx of nutrients from rivers and other polluted water sources (agricultural runoff= excess nitrogen, phosphorus)
There can be red tides near the coastal region caused by
Ceratium (dinoflagellate)
What is the limiting nutrient in red tides
Nitrogen
A higher level of primary productivity supports a higher concentration of ___
Zooplankton and aquatic animals
What is marine snow
As plants and animals near the surface of the ocean die and decay, they fall toward the seafloor, just like leaves and decaying material fall onto a forest floor. In addition to dead animals and plants, marine snow also includes fecal matter, sand, soot, and other inorganic dust.
explain marine carbon pump
The carbonate pump starts with marine organisms at the ocean’s surface producing calcium carbonate This CaCO3 is what forms hard body parts like shells.The formation of these shells increases atmospheric CO2
Particulate organic carbon, created through biological production, can be exported from the upper ocean in a flux commonly termed the biological pump
What happens in the ocean between 300 and 1000 m
Chemoheterotrophs degrade organic matter that falls from the photic zone
What are the conditions and who live in the area 300 to 1000 m
2-3C
Psychrophiles
What happens below 1000 m and who live there
Organic matter is scarce, oligotrophic, no light. Very few microorganisms ( psychrophylic and barophylic or barotolerant)
What organisms was found at 5000 m deep
Xenophyophore- large protist
Hydrothermal vent is a source of
Heat, nutrients, electron donors, electron acceptors
What are tube worms
Symbiosis with sulfur oxidizing chemoautotrophs. Tube worms trap and transport nutrients to the bacterial symbionts
Lake is more ___ compared to the ocean
Highly variable
Microbial populations in the lake depend on
The availability of nutrients, and the availability of light and oxygen. Limited by the availability of nitrogen and phosphorus
Mixing and aeration in lakes and rivers
Lakes (poor mixing/ aeration)
Rivers (good mixing/ aeration)
What are oligotrophic lakes
N and P are limiting
What are conditions in oligotrophic lakes
Growth of aerobic chemoheterotrophs is limited by nutrient supply; oxygen concentration remains high: Rate of oxygen dissolution is higher than the consumption rate
Oxygen saturated
Lake remains aerobic even at depth and organic matter is degraded completely
Clear water (deep penetration of light)
Example of an oligotrophic lake
Lake in the mountains
Eutrophic lake is
nutrient rich
Describe eutrophic lake
Primary production is high (algal bloom), availability of organic matter is high
Rapid growth of chemoheterotrophs, rapid depletion of dissolved oxygen
Low oxygen
Anaerobic zones are created
Poor light penetration
What are health risks in eutrophic lakes
Pathogens, bloom of cyanobacteria/algae (secrete toxins)
Example of eytrophic lake
a pound, blooming lake
What happens at the bottom sediments in eutrophic lake
They are anaerobic and contain organic matter (dead primary producers) which support growth of denitrifiers, methanogens and sulfate reducers (H2S)
What eutrophic anaerobic organism use for photosynthesis
Uses H2S as electron do not and produces sulfate, which is used by sulfate reducers
What gives a bad odor to the lake
Excessive production of organic acids from fermentation
What is bad in eutrophic lake for animals
The lack of oxygen and/or presence of H2S may kill fish and other aerobic organisms
What can happen as a result of summer stratification
Anaerobic zones get created
What is epilimnion and how it get formed
As the air temperature increases, the surface water is warmed resulting in the formation of a warm upper layer-epiliminion- less dense, aerobic
What is hypolimnion
The colder, bottom layer, denser anaerobic - is seperated from the epilimnion by a zone of rapid temperature change
What is the name of the zone of rapid temperature change between epilimnion and hypolimnion
thermocline
In what seasons the lake has thermocline
Summer and winter
What happens in spring and fall with the water in lake
It does have zones , it is circulating
In spring-> 4 C
In fall-> 10C
The mixing brings the nutrient back up the water column
What is the result of good mixing. aeration in rivers
Ensures that organic matter, within limits, is degraded effectively ( no fermentation, no H2S production)
Excess organic matter in rivers can result in
Anaerobic areas with consequences similar to those in eutrophic lakes
What is pollution of freshwater
Deliberate discharge of effluents into a waterway-> major source is sewage
Characterize sewage water
It is rich in organic matter and contains a large number of organisms (some may be pathogens)
What is BOD
Biochemical oxygen demand-- it is used ti measure the extent of pollution by organic matter.
In polluted water is there a lot of oxygen
Water tends to become anaerobic, microbial metabolism: fermentation, sulfate reduction, nitrate reduction
What is the biofilm
Microbial cells embedded inside an extracellular matrix. usually produced by a mixed population of species
Explain the structure of biofilm
Extracellular matrix composed of proteins , polysaccharides, DNA
What is the advantage of the biofilm than an individual cell
Cells inside the biofilm are more resistant to stresses that planktonic (free-living cells)
Where biofilms are found
In water systems( natural and man-made), on wet surfaces, growing on medical devices, etc.
Water borne pathogens are coming from
They grow in the intestinal tract and transmission is mediated by fecal contamination of water supplies
Sources of water infection
- Potable water (drinking and food preparation)
- Recreational water (swimming)
7 water-borne bacterial pathogens and viruses
- Salmonella typhi
- Vibrio cholerae
- Shigella spp
- Salmonella spp
- Campylobacter spp
- Enterovirus:norovirus, rotavirus
- Hepatitis A virus
Salmonella typhi causes
Typhoid fever in humans, systematic infection, healthy carriers
Vibrio cholerae causes
cholera, severe diarrhea (enterotoxin)
Shigella spp causes
Shigellosis; bacterial dysentery (bloody diarrhea, inflammation of the intestinal mucosa)
Salmonella spp ( other than typhi) causes
Salmonellosis
Gastroenteritis
Campylobacter spp causes
Gastroenteritis, most common cause of gastroenteritis in Canada
The name of the organisms that cause amoebic dysentery
Entamoeba histolytica
What does Giardia lamblia cause
Giardiasis (backpacker’s disease/beaver fever), chronic diarrhea,
How can you get Giardia lamblia
often associated with drinking water in wilderness areas ( beavers and muskrats are frequent carriers- source of contamination of streams)
What does Crystosporidium parvum cause
Chronic and acute diarrhea. Is not a problem for healthy individuals, but a major problem for immunosuppressed individuals
Crystosporidium parvum the presence in sewage and river waters
In sewage (90%) 75% in rover water
What are the problems with cysts of Crystosporidium parvum and Giardia lamblia
resistant to a number of disonfectants, including chlorine
C.parvum cysts are not effectively removed by filtratin process in water-plants, because they are too small
Most water-borne pathogens are associated with
Fecal material
How the water quality is assessed
Test for organisms that are present in large amounts in feces. If these organisms are there, there is a chance that the water may also contain pathogens
Two indicators of water quality
- Coliforms
- Fecal coliforms
What are coliforms
Includes a variety of bacteria not all of intestinal origin. Facultative aerobic, Gram-negative, non spore-forming, rod shaped that can ferment lactose with gas formation within 48 hours at 35 C.
What are fecal coliforms
Coliforms derived from the intestines of warm-blooded animals (can grow at 44.5C, thermotolerant)
What is the organism that serves as an indicator of fecal contamination
The presence of fecal coliforms, especially E.coli
Why the absence of fecal coliforms does not ensure goof water quality
Cysts are more resistant than fecal coliforms
What is MPN
Most probable number
Test for coliforms: samples are added to lactose broth, If gas production is detected, test is positive
Then the tables are used to estimate the MPN of coliforms in the original sample
Describe membrane filtration test
Test for coliforms and fecal coliforms
Can test large volume of water (100 ml)
Faster and easier than MPN
Eosin-methylene blue medium is selective and deferential for
Lactose-fermenting bacteria
What are the aims for water treatment
- Remove pathogens
- Improve clarity of water
- Remove compounds that give bad smell or taste
- Soften the water
Steps in water treatment
1) Sedimentation
2) Flocculation treatment
3) Filtration
4) Disinfection
Describe what happens during sedimentation step
- Water is left to stand in a reservoir
- Allow large particle (sand) to settle
Describe what happens during flocculation treatment step
- Coagulant is added
- Water is transferred to a flocculation basin and allowed to settle for 6 hours
- As the flocs(flaky participates) form, they trap fine particles (clay, bacteria, viruses, protists)
- Some organic chemicals are also absorbed by the flocs
How much bacteria are removed during flocculation treatment
around 80% of bacteria , color and particles
What is happening in filtration step
The water is filtered through sand to remove remaining particles, even more bacteria and any remaining G. lamblia cysts
How many bacteria is removed after filtration
98-99.5%
What is done with filtration to avoid clogging
Backflushed
What is done during disinfection step
CHLORINATION->Chlorine is very reactive in water, it forms strong oxidizing agents. It kills remaining microorganisms, neutralizes most of the chemicals that give water a bad smell/taste
What is residual chlorine
Amount of chlorine that remains in the water leaving the treatment plant. Desired/ required to protect the distribution system
Ozone is more effective that chlorine ( kills G.lamblia and C.parvum cysts). Why it is not so widespread?
Very short half-life
What is the threshold for safe water for humans
Less than 10 coliforms /100 ml
less than 1 fecal coliform/ 100 ml
What are the ais for wastewater( sewage) treatment
- Reduce BOD(remove/ destroy organic matter)
- Destroy pathogens
What happens during primary treatment of sewage water
Sedimentation tanks: 40-70% of suspended solids settle. Produces primary sludge (Dried and incinerated or secondary treatment).
Primary treatment reduces the BOD to__ and bacteria by ___
BOD to 25-40%
Bacteria by 25-75%
What happens after primary treatment
Wastewaters can be discharged to waterways or go though secondary treatment: use microorganisms to reduce the BOD and the concentration of bacteria further
What is trickling filter, how it reduces BOD and bacteria
Liquid from primary treatment that 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%
What is activated sludge, how it reduces BOD and bacteria
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. BOD reduced by 85-95%, bacteria by 90-98%
What happens after the sludge is created
The primary and secondary sludge, containing cellulose and other organic compounds, is subjected to microbial digestion under anaerobic conditions. CH4 produced can be used to power the treatment plant. BOD reduced by 90%. Material that remains is incinerated or buried.
What is tertiary treatment
May involve
- Biological treatment( ponds: algae)
- Flocculation
- Filtration
- Chlorination or ozonation
How can the final liquid effluent be used
It comes after all 3 treatments and may be suitable for drinking (coliforms and fecal coliforms below limits)
What is septic tank
-minimal treatment of sewage
-Within the tank: settling of the material and minimal sludge digestion- requires periodic emptying
BOD reduced by 60%
What does the leaching to the fields do with the water from the sepric tank
The water still have a lot of coliforms. It reduces amount of water in the tank. Soils act as a filter and organisms decompose organic matter. BUT careful not to contaminate groundwater and nearby waterways
