Exam 2 Flashcards

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1
Q

Role of “movement” in biogeochemical cycles? What affects “movement”?

A

Biological vectors can move materials against chemical or physical gradients.

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2
Q

Role of “sticking” in biogeochemical cycles? What affects “sticking”?

A

-determines retention
-impacts how available a material is (more stuck less available)
-chemical properties (solubility, charge, size) influence stickiness.

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3
Q

Role of “change” in biogeochemical cycles? What affects “change”?

A

-phase changes, changes in bonds
-often coupled with changes in mobility
-storage and release of energy

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4
Q

Cycling takes place via _________.

A

Redox reactions

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5
Q

Major pools and fluxes in N cycle?

A

pool - atmosphere
flux - internal cycling

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6
Q

Chemical/physical processes in N cycle?

A

-Biological nitrogen fixation makes N bioavailable
-plants and marine biomass have shortest turnover time
-atmosphere has longest turnover time

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7
Q

What are anthropogenic fluxes like in the N cycle?

A

similar in size to nitrogen fixation fluxes because we have doubled the N input from using/making fertilizers

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8
Q

Major pools and fluxes in P cycle?

A

pool - sediments
flux - internal cycling

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9
Q

Chemical/physical processes in P cycle?

A
  • weathering (physical) makes P bioavailable
  • internal cycling has shortest turnover
  • belowground pools have longest turnover
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10
Q

What are anthropogenic fluxes like in the P cycle?

A

more than doubled the rate at which P has changed from non-bioavailable to available (increased weathering and increased mining of P for fertilizers)

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11
Q

Similarities between P and N cycles?

A
  • abiotic pools are larger than biotic pools
  • humans have doubled the rate at which N and P become bioavailable
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12
Q

Differences between P and N cycles?

A
  • P cycle is more linear than N cycle
  • No atmosphere component in P cycle
  • N cycle has a lot more biological processes involving organisms
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13
Q

Watershed

A

topographic area that is drained by a stream / total land area above some point on a stream or river that drains past that point and that is enclosed by a continuous hydraulic drainage divide

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14
Q

Hydrologic Unit Code (HUC)

A

code used to classify and divide a land area based on hydrologic features

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15
Q

What are some of the different HUC orders?

A

HUC 2 : 21 - regions
HUC 4 : 221 - subregions
HUC 6 : 352 - basin
HUC 8 : 2149 - subbasin
HUC 10 : 22000 - watershed
HUC 12 : 160000 - sub watershed (ALLEN CREEK)

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16
Q

Why take a watershed approach?

A
  • limits are defined clearly by topography and runoff patterns
  • entire area is physically linked by water flow
  • upstream processes/activities directly impact downstream areas
  • shows how the surrounding land-use can impact water
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16
Q

What factors control stream flow?

A

topography
vegetation
climate
geology

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16
Q

Watershed drawbacks?

A

watersheds provide boundaries for management, but do not comply with “political” boundaries

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17
Q

What factors control watershed water quality?

A

sediments
nutrients
organic matter
other contaminants

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17
Q

Infiltration

A

water soaks into the ground - depends on:
- soil characteristics (clay vs sand)
- soil saturation (saturated soil cant absorb more water)
- land cover (impervious “fast lane” and vegetation allows water to seep into ground and slows runoff)
- slope

18
Q

Evapotranspiration

A

evaporation - depends on temperature and wind
transpiration - depends on land cover and primary production

19
Q

water balance equation

A

P - R - Et = ^S

20
Q

P = precipitation

A

varies most over time and is sensitive to climate change

21
Q

Et = evapotranspiration

A

most sensitive to land use change
- less vegetation cover
- pavement does not infiltrate, so water accumulates and evaporates
sensitive to climate change

22
Q

^S = change in storage

A

most directly relates to water availability for people
assumed to be 0

23
Q

Key Biological Components of Aquatic Ecosystems

A

Phytoplankton (access to sun)
Periphyton - benthic phytoplankton (can collect more nutrients/oxygen)
Macrophytes - rooted and free floating (shallow water, access nutrients AND sunlight)
Bryophytes - mosses (withstand heavy stream flow but could be covered easily losing access to sunlight)

24
Q

Allochthonous Inputs

A

particulate and dissolved organic matter introduced from a different environment
(NET HETEROTROPHIC)

25
Q

Autochthonous inputs

A

photosynthesis by algae and other aquatic plants which is self-introduced
(NET AUTOTROPHIC)

26
Q

CPOM - Coarse Particulate Organic Matter

A

leaves, needles, wood
pulsed seasonally (BIGGEST - more towards headwater streams)

27
Q

FPOM - Fine Particulate Organic Matter

A

breakdown of CPOM
feces
soil particles from surrounding land and streambank (MIDDLE - more downstream)

28
Q

DOM - Dissolved Organic Matter

A

Typically largest pool of OM
can be important energy source
sources are groundwater, surface flow, and leachate from leaves
(SMALLEST - in more open water)

29
Q

Lentic

A

standing water such as lakes and ponds

30
Q

Lotic

A

running water such as rivers and streams

31
Q

Riparian Zone

A
  • dissipates flood water
  • moderates drought
  • store surface waters
  • reduces erosion
32
Q

Hyporheic Zone

A
  • active exchange between groundwater and surface water
  • areas of strong oxidation and biogeochemical gradients
  • helps regulate stream temperature, esp. in small streams (active exchange between groundwater and surface water)
33
Q

Lake Mixing - Summer

A

Summer water is in layers that do not mix with each other, different levels of circulation, so the nutrients in different layers do not mix

34
Q

Lake Mixing - Fall

A

Overturn - thermal stratification, mixing between layers

35
Q

Lake Mixing - Winter

A

Water is under a sheet of ice, 4 degrees C, so there is not much circulation at all

36
Q

Lake Mixing - Spring

A

Overturn - thermal stratification, mixing between layers

37
Q

Watershed Order

A

1 meet 1 = 2
2 meets 2 = 3
3 meets 3 = 4
and so on…

38
Q

How does land-use and urbanization have an effect on stormwater runoff?

A

rural - steady even runoff
urban - “flashy” response then slow runoff after

39
Q

Discharge

A

cross sectional area (distance x depth) x velocity

40
Q

Load

A

tells us how much nutrients is entering the water body

discharge x concentration (kg/d)

41
Q

Yield

A

gives an idea of the impact of different land uses

load / area (kg/d/ha)

42
Q

Nutrient Calculation

A

y = mx + b
x = absorbance

43
Q

Schoonover et al

A

As land use becomes more urbanized, stream water quality declines - fecal coliform bacteria in urbanized areas consistently exceeded EPA’s criterion (during baseflow and to greater extent during stormwater).

44
Q

Johnson et al

A

Large increases in dairy production were coincident with declining nitrate concentrations which SUGGEST that dairy management practices may have improved.

BUT

In reality, dairy production was fueled by large imports of feed, which meant that nitrate was going to other watersheds elsewhere NOT the Fall Creek Watershed.

45
Q

Duan et al

A

Phosphorus release from sediments was temperature dependent.

P increased with watershed impervious surface and was lowest in small watersheds with forests/low-density residential land.

46
Q

LTHIA

A
  • Commercial contributed most to heavy metal runoff
  • Commercial produced most total runoff
  • Water quality becomes worse as moves from forest to agricultural to commercial