NRES 251 Final

How do we measure groundwater elevation in the field?

• Slotted PVC wells or piezometers are installed to access groundwater.

• Water depth is measured continuously with transducers or manually in the field.

Determine which direction groundwater flows

Groundwater flows from high to low hydraulic head very slowly

Understand and be able to use Darcy’s Law based on real life data

Darcy’s Law:

• Q = s · K · A

• s (Hydraulic Gradient): Difference in hydraulic head between two wells / distance between wells (ft/ft)

• K (Hydraulic Conductivity): Soil’s ability to transmit water (ft/day)

• A (Cross-Sectional Area): Area the groundwater travels through (ft²)

Identify all the proper structures commonly observed in groundwater and understand what is required for unique groundwater attributes to develop

Hydraulic Conductivity (K):

• Varies widely due to differences in soil structure.

• Larger pores or fractures = higher K.

• In the field, K is often measured directly (e.g., slug test) due to mixed soil/media types.

Understand the structure of H2O and why this structure results in unique properties

• Water (H₂O) has 2 hydrogen atoms covalently bonded to 1 oxygen atom.

• Its dipolar structure creates slight positive and negative charges.

• Water molecules stick to each other (cohesion) and to surfaces (adhesion).

• Hydrogen bonds constantly form and break, keeping water dense in liquid form.

Identify how water molecules bind to each other

Cohesion

Describe all the specific properties of water that make it unique

• Only substance on the Earth’s surface that can be found in all 3 states (solid, liquid, and vapor)

• Liquid water has one of the highest specific heat capacities of substances of Earth

• Universal solvent – dissolves polar substances very well due to dipolar nature

Describe the variables commonly used to assess water quality

• Physical – Temperature, Turbidity/Clarity

• Chemical – Nutrients, Road salts, Conductivity, Heavy metals, Organic pollutants (pesticides, hydrocarbons, PCBs, emerging contaminants), Acidity

• Biological – Dissolved Oxygen, BOD, COD, Chlorophyll

• Rapid Bioassessment – IBI (Index of Biotic Integrity), EPT (Ephemeroptera, Plecoptera, Trichoptera)

Be able to understand the water quality parameters we collected during lab and why they may change in an aquatic ecosystem

• Turbidity – how well light can penetrate the water

• Nutrients – when available in excessive amounts on no limitations → excessive primary production

• Chloride is emerging as a potential contaminant in waterbodies

• Heavy Metals – cause neurologic disorders, cancer, and other internal organ diseases

Bioassessment – why is bioassessment used quite frequently by federal/state agencies

• Chemical tests only show a snapshot in time and may miss pollutants or interactions.

• Bioassessment uses the health of living organisms to detect long-term or unexpected pollution, including synergistic effects.

• Often more cost-effective and informative over time.

Explain the process of eutrophication

increase in organic matter (typically N or P) that results in DO depletion

Describe all the ecological and anthropogenic concerns regarding excessive algal growth in aquatic ecosystems.

Toxins, negative effects on tourism, hypoxia

Understand all the nitrogen processes, the conditions they occur in, and the products/reactants involved

• Nitrogen Fixation:

  • N₂ → Organic N

  • Bacteria (Rhizobia, cyanobacteria), aerobic, high energy

• Mineralization (Ammonification):

  • Organic N → NH₄⁺

  • Decomposers, aerobic/anaerobic

• Nitrification:

  • NH₄⁺ → NO₂⁻ → NO₃⁻

  • Nitrosomonas, Nitrobacter, aerobic only

• Assimilation:

  • NH₄⁺ or NO₃⁻ → Organic N in plants/microbes

• Immobilization:

  • NH₄⁺ or NO₃⁻ → Microbial biomass

• Denitrification:

  • NO₃⁻ → N₂ or N₂O gas

  • Denitrifiers, anaerobic, needs organic matter

• Leaching:

  • NO₃⁻ lost with water → groundwater/surface water

• Sorption/Desorption:

  • NH₄⁺ ↔ Soil particles (clay/organic matter)

• Erosion:

  • Soil-bound NH₄⁺ transported to waterbodies

Determine the behavior of nitrogen compounds in the water/soil environment

• Fixation – Bacteria convert N₂ → organic N (requires energy)

• Mineralization – Decomposers release NH₄⁺ from organic N

• Nitrification – NH₄⁺ → NO₂⁻ → NO₃⁻ (aerobic bacteria)

• Sorption – NH₄⁺ sticks to soil; desorbs if outcompeted

• Assimilation – Plants take up NH₄⁺ or NO₃⁻

• Death – Returns organic N to soil

• Immobilization – Microbes take NH₄⁺/NO₃⁻ for growth

• Erosion – NH₄⁺ on soil particles lost to water

• Denitrification – NO₃⁻ → N₂/N₂O (anaerobic + organic matter)

• Leaching – NO₃⁻ easily moves with water

How have humans altered the global nitrogen cycle

• Inorganic fertilizer – Increases nitrate and ammonium

• Manure additions – Increases organic nitrogen, leading to more ammonium and nitrate over time

• Deposition – Adds nitrate to the environment

Understand all the phosphorus processes, the conditions they occur in, and the products/reactants involved

•Driven by physical processes and plant uptake.

• Phosphorus binds easily to cations:

  • In soil: sticks to Al³⁺/Fe³⁺ in clay.

  • In water: forms solids with Ca²⁺ and settles.

• Leaves land mainly through erosion or poor manure management (e.g., CAFOs).

• In lakes, phosphorus can resuspend and is difficult to remove permanently.

Determine the behavior of phosphorus compounds in the water/soil environment

• W – Weathering (releases orthophosphate from minerals)

• U – Uptake/Immobilization (plants/microbes use P for ATP)

• M – Mineralization (decomposers release orthophosphate)

• S – Sorption (P binds to clay via Al/Fe)

• E – Erosion (moves bound P to waterbodies)

• P – Precipitation (P forms insoluble solids with Ca, Mg, Fe, Al)

How have humans altered the global phosphorus cycle

• Inorganic fertilizer adds excess orthophosphate

• Manure overuse builds up organic phosphorus in soils

• Poor erosion control causes phosphorus runoff into waterbodies

Describe in-stream formation of compartments/habitat types

• Riffle – pollution intolerant, low predation (Caddisflies, darters,

• Run – predators (trout, dragonfly larvae, etc.)

• Pool – pollution tolerant, larger organisms (Suckers, blackfly larvae, etc.)

Explain why streams migrate

• Individual stream substrate is being moved every day

Understand how lakes are formed and why different formation results in different lake morphologies

• Glacial lakes form from glacial movement, leaving behind outwash, till, and ice blocks.

• Rift lakes form where tectonic plates pull apart.

• Volcanic lakes form in volcanic craters.

Explain how trophic status in combination with stratification can impact lake function (i.e., how do lakes develop low oxygen conditions)

• Stratification – separates hypolimnion from atmospheric input of O2(g)

– Oligotrophic – little primary production/organic matter → no % DO variation

– Eutrophic – high primary production/organic matter → DO is depleted in hypolimnion due to decomposition

• Turnover events replenish water column with O2

How do we define wetlands?

a. What are the unique properties that help define a wetland?

b. How do these properties develop?

Saturated soils or standing water persist long enough in the growing season to support:

• Hydric soils – formed in low-oxygen conditions.

• Hydrophytic vegetation – plants adapted to low-oxygen environments.

What kind of functions do wetlands provide?

• Water Storage, groundwater recharge, carbon storage, nutrient removal, habitat