Exam 2 Flashcards
1
Q
What are the major pools in the global N cycle?
A
Atmosphere < Benthic Sediment and Rocks < Dissolved N in oceans
The major pools for nitrogen include the atmosphere and soil, while phosphorus pools are primarily in soil and sediments.
2
Q
What are the major fluxes in the global N cycle?
A
Internal Cycling in oceans and plants, Biological fixation, Denitrification
3
Q
What are the major pools of the global P cycle?
A
Sediments < Dissolved P in oceans
4
Q
What are the major fluxes of the global P cycle?
A
Internal cycling (marine, plants)
5
Q
What is the role of biology in the global N cycle?
A
N-fixation converts N to biologically available forms (ammonia), fixation, denitrification by microbes, internal cycling
Biological processes convert atmospheric nitrogen into forms usable by plants, while phosphorus cycling involves biological uptake and release.
6
Q
What is the role of biology in the global P cycle?
A
Important component of DNA and RNA, biotic pools much less than abiotic, biologically mediated internal cycling
7
Q
What are the similarities between the global N and P cycles?
A
Abiotic pools store much more than biotic ones, internal cycling isn’t important.
They both play crucial roles in ecosystem productivity and nutrient availability.
8
Q
What is a watershed?
A
Topographic area that is drained by a stream; the total land area above some
point on a stream or river that drains past that point and is enclosed by a continuous hydraulic drainage divide
Watersheds can vary in size and are critical for managing water resources.
9
Q
What are Hydrologic Unit Codes (HUC) used for?
A
They are used to identify and categorize watersheds, US is divided into 6 nested levels of watersheds (Region, subregion, basin, subbasin, watershed, sub-watershed)
These codes help in water resource management and planning.
10
Q
What are the benefits of a watershed approach to water quality management?
A
- Limits clearly defined by topography and runoff patterns
- Entire area physically linked by water flow
- Upstream activities directly impact downstream areas
- Watersheds provide management boundaries
A watershed approach considers the interconnectedness of land and water.
11
Q
What are the drawbacks of a watershed approach to water quality management?
A
- High complexity
- Potential conflicting interests among stakeholders
- does not comply with “political” boundaries
The challenges can complicate management efforts.
12
Q
What factors control stream flow?
A
- Precipitation
- Infiltration
- Land use
- Soil saturation , soil characteristics
- Vegetation cover
- slope of the land
- storage in reservoirs
- water use by people
These factors influence the timing and quantity of water entering streams.
13
Q
What factors control the quality of water in a watershed?
A
- Land use practices
- Pollution sources
- Natural processes
Different land uses can lead to variations in water quality.
14
Q
What are the reservoirs in the basic hydrologic cycle?
A
- Atmosphere
- Surface water (Rivers, Lakes, Oceans)
- Groundwater
- Soil moisture
Understanding these reservoirs is essential for water management.
15
Q
What are the pathways in the basic hydrogeologic cycle?
A
evaporation, condensation, precipitation, runoff, infiltration, transpiration
16
Q
Fill in the blank: The water balance equation helps understand how different components vary over _______.
A
space and time
17
Q
What is the water balance equation
A
P - R - Et = change in S
18
Q
Use the water balance equation, if given
the input parameters and that you understand how the different components of the equation vary over space and time and in response to changing land-use
A
- P = Precipitation during time interval t
- R = Total water yield or streamflow at t (aka R)
- Et = Evapotranspiration at t
- change in S = change in storage at t
19
Q
How does land use influence the hydrologic cycle in a given watershed?
A
Increased impervious surfaces and deforestation increase runoff and decrease infiltration.
Urbanization can increase impervious surfaces, leading to increased runoff.
20
Q
How does urbanization influence the hydrologic cycle in a given watershed?
A
Decreased infiltration, increased surface runoff, increased runoff speed, increased runoff efficiency (storm drains), increased evapotranspiration (vegetation removal), increased infiltration due to irrigation and leakage, increased water withdrawals and inter-basin transfers
21
Q
How do impervious surfaces influence the hydrologic cycle in a given watershed?
A
Decreased infiltration, increased surface runoff, Decreased evapotranspiration (vegetation removal),
22
Q
How does slope influence the hydrologic cycle in a given watershed?
A
increased slope, increased speed of runoff
23
Q
How does vegetation influence the hydrologic cycle in a given watershed?
A
Decreased evapotranspiration due to vegetation removal, less plants obstructing flow of water and erosion.
24
Q
How does soil saturation influence the hydrologic cycle in a given watershed?
A
increased saturation reduces infiltration and therefore impacts groundwater recharge
25
What are the key biological components of aquatic systems?
- Aquatic Plants (algae, etc.)
- Bacteria
- Invertebrates
- Vertebrates
## Footnote
Each component plays a role in ecosystem function and health.
26
What is the dominant source of carbon to support the trophic structure
(autochthonous vs allochthonous) in freshwater ecosystems?
Allochthonous C inputs = from outside aquatic system, from terrestrial ecosystem, popular in smaller streams
Autochthonous C inputs = (Auto… self) Generated within that system by algae and aquatic plants, popular in larger streams/lakes
## Footnote
This relates to whether a system is net autotrophic or heterotrophic.
27
What is the P/R ratio? What does it tell us?
Ratio of photosynthesis/ Respiration … tells us where C comes from in ecosystem
28
What is a net heterotrophic ecosystem?
Respiration > photosynthesis (common in places where lots of terrestrial inputs)
29
What is a net autotrophic system?
Photosynthesis > respiration (only really in big rivers)
30
How does the dominant source of carbon relate to whether a system is net autotrophic or heterotrophic?
Net heterotopic = lower P/R ratio bc more terrestrial inputs and respiration
Net autotropic = higher P/R ratio bc more C generated in system via processes like photosynthesis
31
What are the main types of organic matter in aquatic ecosystems? What are
their characteristics, where do they come from, how do they relate to stages of
leaf decomposition in a stream channel?
CPOM = Coarse Particulate Organic Matter
(Leaves, needles, wood, other plant & animal parts)
FPOM = Fine Particulate Organic Matter (Breakdown of CPOM, Feces, Soil particles from surrounding land/ streambank)
DOM = Dissolved Organic Matter
(Typically largest OM pool, low bioavailability, important energy source, wide variation in bioavailability)
(Sources: groundwater, subsurface/ surface flow, leachate from leaves, throughfall)
## Footnote
Each type has distinct characteristics and impacts on macroinvertebrate feeding groups.
32
How do the main types of organic matter in aquatic ecosystems impact the types of
macroinvertebrate feeding groups found in the system?
CPOM - scrapers, shredders
FPOM - scrapers, collectors
DOM - scrapers, predators
33
How does carbon cycling differ between
Lotic (rivers/streams) and Lentic (lakes/ponds) systems? What are the differences in the flow regime? The heterogeneity? The riparian zone? How do these differences impact organisms and carbon cycling?
Lotic = flowing
- nutrients/ pollutants carried downstream
- much more heterogeneous
- riparian zone more influential
more rooted plants
Lentic = not flowing
- accumulation of OM and nutrients
- tend to be more homogenous
- riparian zone less influential
more floating plants
34
How does photosynthesis and respiration and the P/R ratio change with
discharge? Why?
As the discharge increases, more sunlight is able to enter the water, increasing the amount of photosynthesis.
In smaller discharge areas, there are more terrestrial inputs, increasing Respiration
35
What stream types that don’t follow the P/R ratio change with discharge pattern and why are they different?
Blackwater streams (huge amount of DOM in water, dark tea color water (not as much light penetration) are always heterotopic no matter how large
Arid lands … not any large plants blocking light, even in small streams … not much vegetation on banks, lots of light availability, not much falling into stream (not enough outside OM to fuel respiration)
36
What is nutrient spiraling in streams?
Combined process of uptake and excretion
Algal and microbial processes recycle limiting nutrients and carbon rapidly
Many sampling methods don’t account for spiraling
## Footnote
It is important for understanding nutrient availability and ecosystem productivity.
37
What are the basic zones of a stream?
Riparian, flood plain, zone of riparian influence, hyporheic zone
38
What is the riparian zone?
The area between land and a river in streams
## Footnote
It serves critical functions like habitat provision and water quality protection.
39
What functions does a riparian zone serve?
timing and amount of water yield
amount of soil for downstream transport, Reduce erosion
Dissipate flood energy, Moderate drought
Moderate in stream temperatures
Transport corridors for: Fish and wildlife, Energy and materials, Sediment
40
What is the hyporheic zone and why is it important? What functions does it
serve?
Active exchange between groundwater and surface water
Area of strong oxidation and biogeochemical gradients
Helps regulate stream temperature, especially in small streams
41
How does velocity vary within a stream channel?
line of maximum velocity, areas of deposition, erosion
42
How do riffles and pools contribute to diversity in stream ecosystems?
results in variable habitats along stream channel
43
What is channelization?
Dredging & straightening of stream channels
44
Why is channelization done?
Divert water for irrigation
Drain fields for agriculture
Increase “usable” land
Prevent flooding
45
Why is channelization a problem?
Altered flow regimes
Many species not adapted to different flows
Loss of habitat (Dredging reduces habitat complexity, reduces total stream area, Loss of floodplains
46
How does the thermal structure of lakes change seasonally?
Thermal stratification: little mixing between layers in summer
47
How does the seasonal change in the thermal structure of lakes influence seasonal patterns in nutrient regeneration in lakes?
temperate lakes: nutrients regenerated in deeper waters cannot reach the surface, vertical mixing in fall brings nutrient-rich water to the surface
48
What is thermal stratification in lakes?
The layering of water in lakes based on temperature differences
## Footnote
It affects nutrient regeneration and aquatic life seasonally.
49
What are the major threats to stream/river ecosystems?
Invasive Species (e.g., zebra mussel, lamprey)
Pollution
Habitat Modification (Channelization, Dams, Draining wetlands, Changes in terrestrial
landscape)
## Footnote
These threats can significantly alter ecosystem structure and function.
50
What are the major threats to lake ecosystems?
Excess nutrient loading
Other pollutants
Water withdrawals
Invasive species
Habitat destruction
Thermal stress
51
What is the river continuum concept?
How ecosystem processes change from small headwater to a river
52
How can the river continuum concept be used to predict how organic matter, C cycling (photosynthesis & respiration) and biota (plants and macroinvertebrates) change with stream order, and between streams and lakes?
Gives structure to think about how aquatic systems change based on the main source of resources, the riparian zone, what organisms live there, and flow volume
53
What are some limitations of the river continuum concept?
Developed for temperate forested
ecosystems in Northeastern US
Doesn’t address role of lateral flow,
floodplains and other local
conditions
54
How does the river continuum concept vary across different biomes or be altered by human activity?
Different climates and precipitation, species of organisms, riparian area diversity
When humans get involved, we change nutrient inputs, landscape, how much OM enters water
55
Examples of point sources?
pipes
ditches
sewage outfalls
56
Examples of non-point sources?
Runoff from agricultural fields, lawns, forestry, parking lots, golf courses etc.
Atmospheric Deposition = gaseous pollutants that dissolve in water
57
Point source vs non-point source pollution: which is more difficult to control?
Non-point source pollution
## Footnote
Non-point sources are diffuse and harder to manage effectively.
58
What are the dominant sources of stream impairment/contamination in the US?
AGRICULTURE
hydromodification, municipal waste, resource extraction
59
What are the dominant sources of stream impairment/contamination in NY state?
Urban stormwater runoff, nutrient eutrophication, habitat/hydrogeologic modification
60
How are causes of water quality impairment in NY state similar/different from the US as a whole, and why might that be?
less from agriculture, more from runoff/nutrients
may be due to more intensely developed areas/cities
61
What living organisms are pollutants?
PATHOGENS (viruses, worms, protozoa, bacteria)
untreated/improperly treated sewage
animal wastes in fields/ feedlots near waterways
meat-packing/ tanning plants that release untreated wastes into water
62
How do living organisms (pollutants) impact the ecosystem?
death, indicator organisms (Fecal coliform), beach closures
63
What pollutants are inorganic toxins?
Mercury, Lead, Arsenic, Cadmium
64
How do inorganic toxins impact the ecosystem?
Very persistent
65
What are the natural sources of inorganic toxins?
natural rock, volcanic eruption, aerosols, wind blown dust chunks, atmospheric deposition
66
What are the anthropogenic sources of inorganic toxins?
From industry, fossil fuels, car wear and tear, medical devices, used batteries, fungicides
67
How do acids (toxins) impact the ecosystem?
acid rain/ acidic fog
changes in aquatic pH
cause sediments to release metals
68
What are the natural sources of acids (toxins)?
Surrounding rocks and soils
69
What are the anthropogenic sources of acids (toxins)?
by product of
industrial processes
mining
Acid rain
mostly from the combustion of fossil fuel
Wastewater discharges from business and industry
70
What pollutants are organic toxins?
pesticides (chemically castrates and feminizes males)
herbicides (kills aquatic plants
cleaning agents
pharmaceuticals
71
How do organic toxins impact the ecosystem?
Persist in organisms
Bioaccumulation –ingested and metabolize, stored in fatty tissues
Biomagnification – more concentrated in successive trophic levels of food web
DDT - Raptors and fragile egg shells
72
What specific pollutants are sediment?
Erosion is removal and sedimentation is deposition
73
How does sediment pollution impact the ecosystem?
~80% of water quality degradation results from erosion
smother bottom dwellers
decrease water clarity, penetration for vegetation
nutrients/toxins attached to sediment particles
can fill waterways/ports, making boat
traffic difficult/ hazardous
74
What are the natural sources of sediment pollution?
erosion
75
What are the anthropogenic sources of sediment pollution?
Farms
construction sites
76
What pollutants are heat pollution?
Cooling water
Run off from parking lots & other dark
surfaces
77
How does heat pollution impact the ecosystem?
Decreases oxygen
Thermal shock – cold-blooded organisms (fish, invertebrates) can’t tolerate rapid temperature shifts
78
What are the anthropogenic sources of heat pollution?
Impervious surface runoff, power plants
79
How does plastic pollution impact the ecosystem?
Microplastics found in fish, humans, drinking water, products made from
freshwater
can absorb toxic chemicals, harbor
dangerous microbes
80
What are the sources of plastic pollution?
Humans.
81
What types of pollutants are nutrient pollutants?
Nitrogen, Phosphorus
82
How does nutrient pollution impact the ecosystem?
Eutrophication = an increase in
the supply of organic matter to
an ecosystem
decreased Dissolved oxygen
83
What are the natural sources of nutrient pollution?
increased plant production within system
84
What are the anthropogenic sources of nutrient pollution?
agriculture, municipal wastes, lawns with fertilizer
85
What is the L-THIA model used for?
To predict runoff and pollutant loads based on land use scenarios
## Footnote
It helps in understanding the impacts of development on water quality.
86
What is the L-THIA model output?
baseline values for planners and scientists to evaluate how altering a landscape will alter the hydrologic response
87
As land use changes from low to high development scenarios (forest ->
agriculture -> urban), how does run-off volume change? Why does this occur?
run off volume increases due to removal of vegetation and increased impervious surfaces
88
As land use changes from low to high development scenarios (forest ->
agriculture -> urban), how does the
nutrient (N&P) loads change? Why do this occur?
nutrient loads increase due to increased runoff
89
As land use changes from low to high development scenarios (forest ->
agriculture -> urban), how does the
pollutant loads of metals and bacteria change? Why does this occur?
pollutant loads increase due to more fecal material in wastewater
90
Recognize watershed discharge patterns for each of L-THIA landcover types, be able to predict patterns in water quality
associated with these landcover types.
From worst to best water quality:
commercial < residential < agriculture < current < forest
91
What techniques are used to evaluate discharge?
- Flow meters
- Cross Sectional Areas
Discharge = Area x Velocity
## Footnote
Accurate discharge measurements are essential for water management.
92
What techniques are used to evaluate nutrient load and yield?
Load = Discharge (kg/L) x Concentration (L/d)
Load (kg/d)/Area (ha)
93
What techniques are used to measure salinity?
Hach meter for conductivity
94
What techniques are used to measure oxygen?
Hach meter for dissolved oxygen
95
What techniques are used to measure temperature?
Hach meter, thermometer
96
What is the difference between load and yield?
Load indicates the total amount of a substance, while yield indicates concentration per area
## Footnote
Understanding these differences is crucial for assessing water quality.
97
What does load tell you?
mass of constituent entering body of water per unit time
98
What does yield tell you?
load/drainage area
Allows comparison between basins of different sizes
99
How does discharge change with changing land use?
increased peak flows and reduced low flows due to decreased infiltration and increased runoff
100
How does nutrient load and yield change with changing land use?
agricultural and urban expansions lead to increased nutrient runoff/ concentrations, causing water quality issues
101
How does salinity change with changing land use?
altered drainage patterns, increased irrigation, and saltwater intrusion
102
How does oxygen change with changing land use?
thermal pollution... decreases dissolved Oxygen
103
Main themes/findings in Schoonover, JE and BG Lockaby. 2006. Land cover impacts on stream
nutrients and fecal coliform in the lower Piedmont of West Georgia.
Journal of Hydrology. 331: 371-382.?
Watersheds with more than 24% total impervious surfaces exhibited higher nutrient and fecal coliform concentrations.
Elevated levels of nitrate, sulfate, and potassium observed in urban watersheds.
Pollutants from stormwater runoff found in higher concentrations in urban watersheds.
Urbanized watersheds have significant increase in fecal coliform levels, exceeding water quality regulations.
## Footnote
This study highlights the long-term impacts of land-use changes on water quality.
104
Main themes/ findings in Johnson, M.S. et al. 2007. Land-use change and stream water fluxes:
decadal dynamics in watershed nitrate exports. Ecosystems 10:1182-
1196.?
Land use improvements improve water quality
Externalization can make it seem like watershed has improved its agricultural methods
Relationship between lower N concentrations and improved dairy management needs more research
105
Main themes/ findings in Duan et al. 2012. Phosphorus export across an urban to rural gradient in
the Chesapeake Bay watershed. Journal of Geophysical Research:
Biogeosciences 117(G1).?
Urbanization leads to eutrophication
Impervious surfaces increase runoff
Increased streamflow increases phosphorus content in water
SRP concentration and release rate are temperature-dependent
Reducing P retention in urban areas remains a priority
