K2 Aquatics: Aquatic Ecosystems

Btw, the nutrient cycling stuff of K1 form CI manual A is combined in here & there is a bit of K1 for aquatics bc I messed up

List the importances of ripairan buffers (3)

• eorsion control inc WQI

• slows waters = inc infiltration

• asthetic - inc property price if next to house

Compare and contrast the characteristics and impacts of turf (as in sterotypical grass lawn) vs native grass. What would you say to someone concerned about the asthetic losses when choosing native over turf?

turf:

• short roots + short grass above = inc erosion bc holds ground less and less filtration

• requries inc maintanenace → more water needed + fertilizer

native grass:

• longer roots, taller body

• adapted to climate so doesnt need extra maintenance

• protects against invasives

• you can still get pretty grass by choosing the right ones for your needs

The place where the atmospheric pressure = water pressure is called the…

water table

How does porosity change as you go down?

Decreases bc of inc pressure from weight

In what situations might the impact of climate change be closer to neutral?

• if the species can adapt/migrate fast enough

• if humans act now to change their practices, they can mitigate cliamte change

How does climate changes’ impact on temperature impact aquatic ecosystems

alter metabolic rate of aquatic specieies → alter/harm productivity, biodiversity, disrupt life cycles

dec in cold water predators = inc in nuissance plants/organisms

How will climate changes impact habitats

Shifts them upwards; inc habitat for warm water fish, dec for cool. If organisms lack dispersal corridors or physical ability to migrate, they may face extinction/exctirption (eg crabs cant move far)

How does changes in ice melt due to climate change impact aquatic ecosystem

dec in ice melt in spring & dec in permafrost = lower water table =…

• lower stream discharge

• dier wetlands = inc risk of peat fires = CO2 released

• drier boreal peats release CO2 + methane bc due to decomposition or burning

Inc sea levels = risk of flooding coastal wetlands

Describe + draw the parts of the carbon cycle. Include the ocean.

CO2 → photosynthesis → primary producer → up the food chain —. plants/animals die → return carbon to ground → turns into CO2 during decomposition or burned as fossile fuel

Respiration → CO2 into atmosphere

In ocean:

CO2 dissolved into water creating carbonic acid

shell making organisms create shells out of calcium carbonate → org die and shells settle to floor → create limestone

for areas with coral reefs (must be shallower waters), same thing

Limestone in ocean subducts / undergoes metamorphism → releases CO2 into atmopshere

Describe nitrogen fixation

N2→NH3→NH4+ (when NH3 reacts with water)

^occurs via…

• lightening (requires high amount of energy to break apart N2 diatomic molecule)

  • N2 + O2 → NO2 => +H2O = HNO3-

• haber bosch process → industrial fixation: high pressure + catalyst @400-500*C

  • processd into urea and ammonium nitrate (NH4NO3)

  • N2 + 3H2 ←→ 2NH3

• via nitrogen fixating bacteria (rhizobia): symmbiotic relationship with legumes (eg beans, soybeans, termites, shipworms, peas, cloves, alafa) living in balls called nodules on the roots

  • rhizobia fix nitrogen into ammonia, legumes give sugars & sends chemical signals to rhizobia in the nodules

What % of the atmosphere is made of N2 and how mcuh of that is actually fixed and why?

85%

5-8% bc of high energy needed to break diatomic molecule

Describe nitrification

NH4+ → NO2- → No3- via aerobic bacteria like cyanobacteria and arachae

Describe denitrification

NO3- → N2 by aerobic denitrficying bacteria (eg Pseudomonas; where NH3 is used as an energy source and NO3- as the oxidizing element)

Note: in deep sediment/hypoxic conditions, ammonia accumulates

Describe leaching

NO3- leached from rainwater (leached more than NH4+ bc of higher CEC)

describe ammonification

microrganisms/deocomposers turn organic nitrogen into NH4+

volatilization

In places with pH > 7: urease OR when fertilizer/manure is left on the surface, it turns into NH3 gas

describe assimilation

NO3- and NH4+ → organic nitrogen (taken up by plants)

Urea (CO(NH2)2 will can also be taken up, but it usually turns into NH4+)

List the top two sources of nitrogen by humans

1. Air pollution

2. Artifical fertilizers

Describe air pollution’s contrubutions to the nitrogen cycle and its impacts

Combustion of fossil fuels produces nitrogen oxides (nitric oxid (NO) > produced than nitrogen oxide (NO2) in cars)

• nitrogen oxide is reddish and poisonous

• nitric oxide is flammable but colorless & will turn into NO2 by combining with O2

impact:

• creates smog: .2 ppm for smog, 0.01ppm for normal conditions

• forms nitric acid when combining with rain water → HNO3

  • damages aquatic life and trees; erodes marble and limestone

Nitric acid may also be created industrially (NH3+O2 → HNO3 + H2O)

• used in fertilizers & explosives

Describe fertilizers’s contrubutions to the nitrogen cycle and its impacts

accounts for half of nitrogen on land

• 90 megatons of biologically fixated nitrogen = 1 million tons of nitrogen created

impact: causes eutrophication

Describe the phosphorous cycle

List and describe sources of phosphorous

List the two methods of stream ordering and describe them

Strahler (most common): add streams only when they are the same, otherwise carry on with largest order. flaw: basically ignores what little streams are contributing

Shreve’s method: additive; may be referred to as magnitutes rather than order; accounts for little streams

For the follow stream, determine the magnitude using strahler vs shreve’s method

Strahler: 4

Shreve: 9

What orders correspond to diff river continuum sections?

1-3: headwaters

4-6: midreaches

7+: lower reaches

Describe the characteristics of the lower reaches

Describe the characteristics of the mid reaches

Describe the characteristics of the headwaters