Ch.27 Environmental Micro

Question 1

what is the hydrologic (water) cycle?

Answer 1

is the cyclic exchange of water between the atmosphere and biosphere

Question 2

what are the steps to the hydrologic water cycle?

Answer 2

1. water precipitates as rain; falls to earth
2. It is returned by evaporation to the air

Question 3

what carries nutrients into the river and what does it increase?

Answer 3

1. water
2. increases BOD

Question 4

what accelerates microbial respiration?

Answer 4

Carbon runoff

Question 5

what is BOD?
Biochemical oxygen Demand

Answer 5

it is the amount of O2 removed from the environment through respiration

Question 6

what creates BOD?

Answer 6

Microbial Oxygen Consumption

Question 7

how is BOD measured?

Answer 7

with how fast oxygen is removed

Question 8

where are dead zones or zones of hypoxia?

Answer 8

large regions of the ocean

Question 9

what is an example of a dead zone or zone of hypoxia?

Answer 9

Gulf of Mexico, off the Louisiana coast

Question 10

when did the dead zone expand?

Answer 10

by 2010 oil spill

Question 11

Heterotrophs in a large region of the ocean that have become dead zones or zones of hypoxia increase in response to what?

Answer 11

the influx of organic nutrients

Question 12

what depletes oxygen in large regions of the ocean that have become dead zones or zones of hypoxia?

Answer 12

aerobic respiration

Question 13

when does eutrophication occur?

Answer 13

from an influx of excess nutrients that triggers hypoxic zones in the water

Question 14

Eutrophication results in high levels of what?

Answer 14

aerobic respiration

Question 15

what decreases the BOD and the level of human pathogens before water is returned to local rivers?

Answer 15

wastewater treatment

Question 16

what are the steps to wastewater treatment?

Answer 16

1. Preliminary treatment
2. Primary treatment
3. Secondary Treatment
4. Tertiary (advanced) treatment

Question 17

what does the preliminary treatment do?

Answer 17

removes solid debris

Question 18

what does the primary treatment do?

Answer 18

fine screens & sedimentation tanks remove insoluble particles.

Question 19

what does secondary treatment do?

Answer 19

microbial decomposition of organic content

Question 20

what does tertiary advance treatment do?

Answer 20

chlorination or other chemical application to eliminate pathogens

Question 21

what is the activated sludge process?

Answer 21

a process for treating wastewater using air and a biological floc composed of bacteria and protozoa.

Question 22

why is flocculation important?

Answer 22

floc formation is critical in promoting the setting of bacteria

associated microbes from the treatment process.

Question 23

what does flocculation yield?

Answer 23

abundant, clarified effluent

Question 24

what is important in floc formation?

Answer 24

filamentous bacteria

Question 25

what is a healthy sludge(brown floc) largely composed of?

Answer 25

Saprotrophic bacteria

Question 26

what does saprotrophic bacteria feed on?

Answer 26

feed on decayed matter

Question 27

what is the protozoan flora composed of?

Answer 27

amoebae ciliated protozoans stalked ciliates

Question 28

true or false? Nitrogen has more oxidation states than any other major biological element

Answer 28

true

Question 29

What can't the nitrogen cycle exist without?

Answer 29

it cannot exist without prokaryotes

Question 30

what is the major accessible nitrogen source?

Answer 30

atmosphere

Question 31

what is artificial nitrogen fixation accomplished by?

Answer 31

by the Haber process

Question 32

what is the Haber process?

Answer 32

it generates fertilizers for agriculture N2+3H2----> 2NH3

Question 33

What is ammonification?

Answer 33

the catabolism of organic N sources (proteins); release ammonia (NH3)

Question 34

The N2 is catalyzed by what?

Answer 34

nitrogenase

Question 35

does N2 fixation function anaerobically or aerobically?

Answer 35

anaerobically

Question 36

what does symbiotic mean?

Answer 36

bacterial associations with certain types of plants

Question 37

what does N2 fixation occur in?

Answer 37

free-living types and symbiotic types of bacterial

Question 38

cyanobacteria in oceans and freshwater compartmentalize N2 fixation in what?

Answer 38

heterocysts

Question 39

what is the formula for N2 fixation?

Answer 39

N2----->NH3----NH4+

Question 40

steps to symbiotic N2 fixation:

Answer 40

1. Rhizobia attaches to root hair 2. An infection thread is formed through which bacteria enter root cells 3. Bacteria change into bacteroids; packed roots enlarge 4. Enlarged root cells form a nodule

Question 41

What is the formula for nitrification?

Answer 41

NH4+--->NO2- ---->NO3-

Question 42

what is lithotrophy?

Answer 42

oxidation of NH4+ provides electrons and energy.

Question 43

what does denitrification represent?

Answer 43

represents anaerobic respiration

Question 44

what does denitrification lead to?

Answer 44

loss of nitrogen from the environment

Question 45

what stimulates denitrification?

Answer 45

influx of nitrate(NO3-) into areas lacking O2

Question 46

what happens in hypoxic areas during denitrification?

Answer 46

anaerobic respiration using NO3- causes: NO2- buildup then used to for N2O

Question 47

what happens when water passes through the ground and picks up nutrients?

Answer 47

carbon runoff accelerates microbial respiration 02 becomes depleted

Question 48

High BOD can threaten what?

Answer 48

viability of fish & other aquatic animals

Question 49

when does high BOD threaten the viability of aquatic animals?

Answer 49

when O2 levels are < 5 mg L

Question 50

what is the process of Eutrophication?

Answer 50

1. influx of N, P boosts levels of phototrophs ex: alage & cyanobacteria; a mat of growth occurs 2. once excess N, P is used up, the algal mass dies and falls to the bottom 3. Hetertropic bacteria on the organic matter feast on organic matter 4. Aerobic respiration depletes oxygen from the water- fish killed