Midterm Flashcards
What is an inland water?
All freshwater bodies. All water landward on land-ocean boundary.
What is an ecosystem?
All biotic and abiotic factors in an environment. “…a biotic community or assemblage and its associated physical environment in a specific place.”
What are natural alterations an ecosystem can have/go through?
-Climate -Nutrients -Light -Turbidity
What are examples of human impacts that alter ecosystems?
-Nutrient and sediment input -Climate change -Toxins -Habitat destruction
True/False: Water bodies are independent from one another.
False.
What are estuaries?
A mix of salty and fresh water, tidal dependent. A river’s connection to the ocean.
What are the physical gradients of aquatic systems?
Turbulence and currents
How does physics influence aquatic ecosystems?
-Influences the type of life-form (drifting vs. attached) -Vertical movement: temperatures, sunlight -Horizontal movement: habitat, **depth**, turbidity, etc.
What are the chemical gradients of aquatic systems?
Dissolved ion concentrations (salts) -ex: High salinity lakes have fewer biodiversity. **Osmotic pressure**
How do geological gradients influence aquatic ecosystems?
By the amount and type of substrates, both dissolved and undissolved, as well as the hydrology via underwater slope and basin infrastructure (seepage, groundwater, etc.)
What biological factors influence and distinguish ecosystems?
Presence/ absence of food resources, predators, refuges, etc.
What are lentic systems?
Lakes, wetlands, ponds
What are lotic systems?
Streams, rivers, anything that flows
What does athalassohaline mean?
Not sea salt inland water. They typically contain Ca & Mg carbonates and sulfates.
What part per thousand defines saline/freshwaters?
3ppt dissolved salts
Why are the oceans generally saltier than inland waters?
Oceans receive inland water runoff and water evaporates more quickly thus increasing salt concentrations. Evaporation rates > precipitation rates.
What is ocean acidification?
Increased CO2 content. CO2 diffuses into oceans from atmosphere.
What distinguishes different kinds of aquatic ecosystems?
The physical, chemical, geological, biological, and climate-scale gradients.
What are the commonalities and major differences of different aquatic systems?
Standing vs running water. Salt content.
What makes lakes saline?
The difference between precipitation and evaporation rates. Net evaporation processes.
Where are the saline lakes in North America?
West side of the continent. Many, but not all, are formed from inland extensions of the sea that became isolated over geological time.
Hypersaline lakes tend to have very simple food webs of few trophic levels, why?
Very few species are able to live in these high salinity environments due to the hyper-osmotic pressure.
What characteristics do freshwater wetlands differ in?
Permanence, depth, vegetation wetlands tend to be small and seasonal
What characteristics do lakes differ in?
Climatic zone, mixing regime, trophic status (fertility), electrolytes (alkalinity, hardness) lakes are larger and are more affected by large scale features
What is the significance of 4 degrees C?
It is the highest density of water. Water sinks at this temperature and causes mixing to occur.
What is the significance of the mixing regime?
It controls the biology of the water.
What are the physical factors that cause lakes to mix on different time scales and at different frequencies?
Temperature, latitudinal location of lake.
How do you calculate the water hardness?
Sum of cations
What can water hardness determine?
Productivity of lake
What is the maximum hardness a lake can reach?
50 ml/L CO2
What is an oligotrophic lake?
A lake with low nutrients, low organic matter, and high hypolimnion O2 content.
What is a eutrophic lake?
A lake with abundant nutrients, abundant organic matter, and low hypolimnion O2 content.
What does a higher volume in lakes mean for nutrient levels?
Higher dilution of nutrients.
What mostly controls plant growth in lakes?
Nutrients!
Describe the Strahler classification. (aka stream order)
Smallest permanently flowing stream is called a “first order” Union of two streams of order n creates a stream of order n+1 Union of a stream of order n with a stream of order <n></n>
**Implication of stream order**
**
What orders are the Ohio, Mississippi, and Amazon rivers?
8th, 10th, 12th respectively
What is the pattern with stream order and size?
Increase in stream order, results in an increase of size. *Exponentially increasing but with lots of variability within a given order
Name two properties of water then compare with other substances and explain its importance to aquatic systems.
Density - Under standard pressure, maximum is 3.94*C, not 0. Expands upon freezing. Allows lake stratification and surface freezing rather than bottom freezing. Absorption of radiation - Large in the infrared region, but moderate in the photosynthetic/visible region. Allows greater heat absorption in surface water, but reduced surface absorption at shorter wavelengths, allowing a greater penetration of PAR.
What is the most important factor in lake water column stability?
Density - it affects phytoplankton growth and hence entire food web.
What is surface tension and its importance in the water column?
A measure of the strength of film at the water surface. It keeps surface waves from breaking; alters heating and cooling. It allows organisms to live in surface film. It decides what wavelength and how much light gets through.
What is viscosity and its importance in the water column?
A measure of resistance to flow. It alters heating and cooling. It makes water act like a “gel” to small organisms. It offers good resistance for swimming.
What amount of absorption is in the infra-red region? And what does it do for the water system?
Large; it moderates temperature extremes.
What amount of absorption is in the photosynthetic region? And what does it do for the water system?
Small; it allows plants to grow deep in clear water.
How much of continental freshwater is frozen in glaciers and icecaps?
77%
How much of Earth’s water is in the oceans?
97.2%
How much of Earth’s water is continental water?
2.8%
How much of Earth’s water is in the atmosphere?
0.001%
What percentage does the deepest water make up Earth’s radius?
0.07%
T/F: Small lakes cover more area than large ones.
True
T/F: Small lakes make up the largest number of water impoundments.
True
T/F: Larger lakes make up the largest area of impoundments.
True
What are the three categories of water usage and their impact in water quality?
Consumption (large changes in quality), physical uses (moderate to severe changes), passive uses (little impact on quality)
T/F: Ohio uses more water annually on average than the US.
True
Why are surface freshwaters used disproportionately (i.e., vs. groundwater) for industrial, agricultural, and domestic supplies?
It’s cheap to use, can be pumped rapidly, usually renewed quickly, traditional water sources, i.e., infrastructure is already in place.
Why have hydroelectric power usage on the decline?
Awareness of dam-effects
T/F: Recreational boating (as a passive water use) is on the decline.
False.
T/F: Freshwater anglers’ expenditures (as a passive water use) are on the decline.
True
Where does our local water come from?
Griggs Reservoir
What happens to water after precipitation?
It is lost in evaporation and evapotransiration
T/F There is a balance between evaporation from ocean and what returns to the ocean via precipitation.
False
What is residence time? (in regards to water)
The amount of time the average water molecule resides in that “box” before moving into another “box” retention time in a body of water
What is a watershed?
An area of land that intercepts and drains precipitation and collects water for a particular stream, lake, or other water body (aka drainage basin or catchment)
T/F Everything that happens to a watershed can affect what ends up in the water.
True
What is flux?
The movement of mass and time
What do the watershed/catchment exports reflect?
Geology, land cover, soils, vegetation, slope, human impacts (fertilizer use, sewage treatment), deposition from air pollutants (acidity, Hg), variation in hydrology (timing and amounts of precip and runoff)
What do the watershed/catchment loading reflect?
Integrated export from watershed, watershed (aquatic system area ratio, aka drainage ratio), upstream aquatic systems (lakes upstream reduce export downstream)
What is the hydraulic water residence time?
The length of time (days or years) required to completely flush a water body. gamma = V/Q
Why should we care about water budgets?
They affect human society.
What are the three sources of storage?
- Precipitation (falls DIRECTLY on water bodies) 2. Surface runoff from watershed 3. Groundwater
What are the four losses in storage?
- Surface outflow 2. Groundwater seepage 3. Evaporation 4. Evapotranspiration
What input and loss terms are easy to measure in the water budget?
Precipitation, surface outflow, evaporation, surface runoff
What input and loss terms are difficult to measure in the water budget?
Underground things, groundwater input, seepage
Give the equation(s) of the hydrological mass balance equation.
Inputs = Outputs + dStorage (or dStorage = Inputs - Outputs)
Precipitation (P) + Runoff (R) + Groundwater (G) = Evaporation (E) + Seepage (S) + Surface Outflow (O) + dStorage
dStorage = P + R + G - E - S - O
Draw a diagram depicting all inputs and outputs of the hyrological balance equation.
If storage is equal to 0, what is the hydrological mass balance equation?
P + R + G = E + S + O
Often P, R, E, and O can be measured, so at a steady state: (list balance equation)
G - S = E + O - P - R
Difficult to measure = Easy to measure
What factors should be considered when choosing a tracer?
Reactivity, negative effects, solubility, ease of measure, toxicity
How was groundwater input in the West Basin of Long Lake determined?
Tracer: LiBr
Outflow was estimated by labeling the lake with LiBr and measuring decline over time, change in storage was measured as change in lake height (staff gauge), R = 0 (no surface inflows), precipitation was measured with a rain gauge, evaporation was estimated as proportion of precipitation (~30%)
Seepage was assumed to be constant for Mirror Lake in both wet and dry weather conditions, but what did a study find to actually be true and what does this show about variables?
A huge variation in runoff, precipitation, and outflow between wet and dry conditions was found, thus seepage has to be variable. This shows that variables are truly difficult to estimate.
What fluxes and other factors can a water budget help estimate?
Chemical fluxes, impacts of nutrients, toxins, pH balance
What different processes lead to lake formation?
Tectonic, volcanic, glacial, etc
How would you predict the distribution of lentic ecosystems relates to vegetation and human population density?
Higher, nutrient-rich vegetation because of a water source and higher amount of farms around lakes for irrigation purposes. Higher human population density - source of water, irrigation for farms, etc
At what latitudes are most of the world’s lakes located? Why?**
45*N, 0*, 45*S
**
T/F Small lakes were initially thought to cover more area of the Earth than large lakes
False. Large lakes initially thought
Why were larger lakes originally thought to cover more area of the Earth?
Small lakes were previously under-sampled
