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174 Cards in this Set
- Front
- Back
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Name 9 Lake Formation Processes
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Glacial, Tectonic, Fluvial, Aeolian, Landslide, Volcanic, Solution, Coastal, Biotic
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Scour Basins
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formed by glaciers
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Moraine Dams
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?
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Kettle Lakes
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Depressions created by partially-buried glacial ice blocks as they melt
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Cirques
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A steep bowl-shaped hollow occurring at the upper end of a mountain valley, especially one forming the head of a glacier or stream
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Ox Bow Lake
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bow-shaped lake formed in a former channel of a river
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Playa Lake
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A shallow temporary sheet of water covering a playa in the wet season
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Paternoster Lakes
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A series of lakes that form in the low spots of a u-shaped valley. They are linked by a stream that flows through the valley. The presence of such lakes is diagnostic of recent glaciation
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Fjords
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A long, narrow, deep inlet of the sea between steep slopes
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Cenote
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freshwater-filled sinkhole typically found in the Yucatán Peninsula
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Graben Lakes
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Formed in adepression in the earth's crust between two parallel faults. A graben lake is a type of lake that forms in the depression of a graben, and tend to be deep lakes.
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Diked Lake
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?
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Caldera Lakes
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Form within a volcano.
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Fetch
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Affect of wind on a lake.
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4 Factors Surface Area Influences
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1. Amount of sunlight entering lake.
2. Quantity of evaporation. 3. Fetch 4. Gas exchange between lake and atmosphere |
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3 Factors That Volume Influences
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1. Mass of water and other materials present.
2. Residence times. 3. Potential for sediment/water interactions. |
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3 Factors Depth Influences
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1. Thermal structure of lake.
2. Vertical mixing patterns. 3. Vertical distribution of biota and biotic processes. |
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Littoral
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Pertaining to the lake shore
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Pelagic
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Pertaining to the open lake
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Bathymetric
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measurement of lake depth
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Warmer water is more or less dense?
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Less
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Maximum water density
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3.98 degrees celcius
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Viscosity increases or decreases w/increasing temperature?
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decreases
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Specific Heat
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Number of calories required to raise the temperature of a substance 1 degree celcius
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Do you have a larger or smaller heat capacity with larger volume?
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Larger
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Light has major influence on (3)
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1. Physical features
2. Amount and distribution of primary production. 3. Spacial distributions of organisms. |
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Light
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Radiation of packets of energy called photons
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Much of light energy hitting water is in what frequency?
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IR
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Light intensity varies w/ (6)
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1. Time of Day
2. Season 3. Latitude 4. Local Weather 5. Shape of landscape surrounding lake 6. Size of landscape surrounding lake |
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Ability of lake to absorb light depends on:
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wavelength
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Absorption (light)
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Diminution of light energy with depth by transformation to heat
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What part of light spectrum is most important to heating lakes?
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IR
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Dissolved substances increase or decrease the absorptivity of water?
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Increase
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DOC facilitates or blocks UV radiation?
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Blocks
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Attenuation
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The sum of light scattering and absorption. The total reduction of light energy with depth.
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3 Ways to Measure Light
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1. Secchi disk: measures light attenuation w/depth.
2. Photometer:measures photon flux w/in a band of wavelengths. 3. Spectroradiometer: Measures photon flux from a specific wavelength. |
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4 Causes of Density Differences in Lakes
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1. Temperature
2. Pressure 3. Solutes 4. Suspended particles |
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Holomixis
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lakes where wind-driven circulation mixes the entire water column
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Epilimnion
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Upper thermal layer of lake
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Hyolimnion
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Lower thermal layer of lake
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Thermocline
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Layer of lake where temperature gradient is greatest.
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6 Types of Thermal Stratification
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1. Amictic: never mixes
2. Cold monomictic: Lake mixes all summer and freezes in winter. 3. Dimictic: stratifies in summer and winter, mixes in spring and fall. 4. Warm monomictic: stratifies in summer, circulates in winter 5. Oligomictic: circulates rarely 6. Polymictic: circulates almost continuously |
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Meromictic Lakes
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Never circulate top to bottom due to density differences caused by salinity differences
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Ectogenic Meromixis
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results when an external source causes a change in salinity of a portion of the
water column |
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Crenogenic Meromixis
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salts are liberated by decomposition in the sediments, and collect in the
monimolimnion. Can occur in relatively deep lakes with little fetch |
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Stability
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Amount of work required to fully mix a lake until it is a uniform density. Work usually performed by wind. Highest stability when most dramatically stratified.
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More or less water goes directly back into the oceans compared to how much evaporates? How about for lakes/groundwater?
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Less; More
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Volume of water in lake determined by (2)
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1. Shape of Basin
2. Balance between sources/losses of water. |
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Sources of Lake Water (3)
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1. Precipitation
2. Inflow from watershed 3. Groundwater |
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Losses of Lake Water (4)
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1. Surface outflow (streams/rivers)
2. Groundwater seepage 3. Evaporation 4. Evapotranspiration |
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Water Residence Time
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Length of time required to completely flush a lakes water
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Water Renewal
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Amount of water required to replace the lake volume in a given time interval.
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Name 5 forces acting on water bodies
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1. Wind
2. Atmospheric Pressure 3. Gravity 4. Coriolis 5. Inflowing rivers and streams |
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Laminar Flow
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Smooth flow
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Name 4 factors that affect whether flow is laminar of turbulent.
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1. Density
2. Density gradient 3. Gravity 4. Velocity gradient |
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Wave height if a function of (2)
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1. Wind speed
2. Fetch |
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Ekman Spirals
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Created by the friction on the lake surface due to the coriolis.
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Langmuir Circulation
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Causes streaks on water surface when wind speeds are high, due to helical circulations
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Surface Seiches
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Wind causes water to accumulate at one end of lake. When wind stops/changes direction seiching starts.
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Which are higher, internal or surface waves?
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Internal
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Metalimnetic Entrainment
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turbulent flow from internal seiches erodes the
metalimnion and deepens the epilimnion. Important for mixing nutrient-rich metalimnetic waters to the surface. |
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Thermal bars
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Shallow water warms faster than the offshore water forming a barrier to
lateral mixing. |
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Oxygen solubility is affect by (3)
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1. Temperature: increasing T decreasing solubility
2. Pressure: increasing P increases solubility 3. Salinity: increasing salinity increases solubility |
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Sources of oxygen in aquatic ecosystems (2)
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1. Atmosphere
2. Photosynthesis |
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Losses of oxygen in aquatic ecosystems (3)
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1. Atmosphere
2. Respiration 3. Chemical oxidation processes |
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Biological Oxidation Demand (BOD)
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Rate at which volume of water consumes oxygen through respiration.
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Factors that affect BOD (3)
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1. Positively correlated with temperature
2. Positively correlated with amount of organic substrate available to organisms 3. Influenced by allochthonous material |
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Orthograde oxygen profile
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Oxygen concentration same throughout lake
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Clinograde oxygen profile
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oxygen concentration high in epilimnion and low in hypolimnion
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Positive heterograde oxygen profile
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oxygen concentration increases at metalimnion
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Negative Heterograde Oxygen Profile
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oxygen concentration decreases at metalimnion and increases slightly into hypolimnion
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Daily changes in oxygen concentration affected most by:
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Light conditions that affect photosynthesis.
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Seasonal changes in oxygen concentration driven mainly by (2)
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1. Seasonal changes in light conditions
2. Seasonal changes in thermal stratification. |
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Winterkill
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Seen in very productive shallow lakes during ice cover. No light can penetrate, respiration exceeds photosynthesis. Fish die.
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Summerkill
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Seen in very productive stratified lakes during summer. Hypolimnion slowly loses oxygen, due to respiration from sediments and falling dead organic material. Oxygen in hypolimnion is depleted, fish needing colder waters die.
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Trophogenic zone
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Where organic matter is produced and photosynthesis is more than respiration.
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Tropholytic zone
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Where no oxygen is produced, but respiration consumes oxygen.
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Winkler Titration
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Used to measure oxygen concentration in water. Electronic Oxygen meter is much less precise.
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Productivity usually limited by
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phosphorus availability
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Phosphorus required for (5)
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ATP, DNA, RNA, bones, scales
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Most significant form of phoshporus in lakes is:
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PO4 3-
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All phosphorus ultimately comes from:
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lithosphere (solid portion of the earth)
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Most particulate phosphorus is in:
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biota
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Loss of phosphorus from lakes is due to (2)
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1. sedimentation
2. flushing |
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Phosphorus is generally found in high or low concentrations in lakes?
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Low
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Sources of phosphorus in lakes (4)
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1. Igneous rocks containing apatite
2. Inflowing rivers/streams 3. Mobile biota (salmon) 4. Humans: sewage, agriculture, detergents |
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Who/what can take up phosphorus directly from the water?
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Plants/bacteria
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How do zooplankton provide phosphorus to lakes?
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Sloppy feeding
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How does phosphorus get out of the sediments?
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Benthos
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Is Fe2+ soluble or insoluble?
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soluble
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Eutrophication
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Increase in nutrient input to a lake.
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Alkalinity
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Acid neutralizing capacity
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Biological nitrogen demand typically depends on its ratio to:
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Phosphorus
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Bacteria and algae can use N in what 4 forms?
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1. Molecular
2. Ammonia 3. Nitrate 4. Nitrite |
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Nitrogen in lakes is gained mostly from the:
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Atmosphere
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Sources of Nitrogen (4)
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1. Nitrogen fixation
2. Dry fall and precipitation 3. Surrounding watershed. Agriculture. 4. Excretion by terrestrial and aquatic consumers. |
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Nitrogen Fixation
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N2 --> RNH2 (organic nitrogen)
Energetically costly. Performed by bacteria. |
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Ammonification
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RNH2 --> NH4+
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Nitrification
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NH4+ --> NO2(-) --> NO3(-)
May be inhibited by DOC. Slowed in acidic bog lakes. Requires oxygen at every step. |
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Denitrification
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NO3(-) --> NO2(-) --> N2O --> N2
Requires anaerobic conditions. Rate decreases in acidic conditions. |
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In oligotrophic lakes NO3- increases or decreases with depth? NH4+?
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Increases; stays the same
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In eutrophic lakes NO3- increases or decreases with depth? NH4+?
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Decreases; increases
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pH of natural waters largely governed by:
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H2CO3
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pH is increased or decreased in hard water when carbonate and bicarbonate increase in concentration?
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Increased
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At low pH, medium pH, and high pH which form of organic carbon dominates?
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CO2; HCO3(-); CO3 (2-)
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Sources of carbon dioxide (3)
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1. Atmosphere
2. Respiration 3. Solution of mineral carbonates |
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Losses of carbon dioxide (2)
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1. Diffusion into atmosphere
2. Uptake during photosynthesis |
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Distribution of pH in oligotrophic lake
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Same everywhere
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Distribution of pH in eutrophic lake
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Decreases with increasing depth.
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Very productive lakes give or take carbon dioxide from atmosphere?
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Take
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Redox potential is affected by (3)
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1. pH
2. Oxygen concentration 3. Temperature |
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Sources of sulfur to lakes (4)
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1. Atmosphere
2. Volcanoes 3. Burning Fossil Fuels 4. Marine Sediments |
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Do SO4(3-), H2S, and FeS increase or decrease w/increasing depth in a eutrophic lake?
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decrease; increase; increase
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Silica usually found in lakes as:
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SiO2
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Main source of Silica
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Feldspar rocks
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Main loss of silica in lakes
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Diatom blooms
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In eutrophic lakes, does SiO2 increase or decrease with increasing depth?
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Increase
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Differences in reproductive behavior of fish due to (4)
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1. Degree of parental care
2. Courtship behavior 3. Time of Spawning 4. Location of Spawning |
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Anadromous
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Spawn in freshwater but spend most of life in saltwater
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Catadromous
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Spawn in marine systems but spend most of life in freshwater.
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Planktivores
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Fish that mostly prey on plankton
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Piscivores
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Fish that prey mostly on other fish
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Benthivores
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Fish that feed mostly on benthic organisms.
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Most important environmental factors that mediate ecology of fishes (5)
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1. Temperature
2. Oxygen concentration 3. pH 4. Light regimes 5. Habitat heterogeneity |
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Fish production of lake influenced most by (2)
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1. Depth
2. Total Dissolved Solids (TDS) |
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Reproductive strategy of rotifers
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Parthenogenesis, occasionally sexual reproduction
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Reproductive strategy of cladocerans
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Parthenogenesis, occasionally sexual reproduction
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Reproductive strategy of copepods
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Sexual reproduction
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Are viscous forces important at high or low reynolds numbers?
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Low
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Zooplankton adaptations to resist predation (3)
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1. Behavioral: avoid visual feeding predators by coming out at night.
2. Morphological: change body shape 3. Life-history: increased allocation of energy to reproduction, decreased size at maturity, decreased age of maturity |
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Zooplankton provide important source for (2)
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Nitrogen and phosphorous
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At low N:P ratio, do blue-green algae dominate the system?
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Yes
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Factors that affect growth and cell division rates of algea (2)
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1. Light
2. Temperature |
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Nutrient starved cells have higher or lower uptake rate than nutrient rich cells?
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Higher
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Cell quota
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cellular content of a nutrient in a phytoplankton cell. A minimum cell
quota is required for growth and reproduction of phytoplankton. |
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Luxury Uptake
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ability of some phytoplankton species to uptake more limiting nutrients than they need for growth and reproduction. Adaptation to life in patchy environment.
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Vectors for exotic species introduction (4)
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1. Ballast water
2. Government stocking 3. Aquarium trade 4. Bait fish |
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Primary Production
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Rate at which carbon is fixed in photosynthesis.
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Standing stock
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Measure of plant biomass.
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Strategies for measuring primary production (2)
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1. Light and dark bottle method
2. Carbon 14 uptake |
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Factors that control rate of primary production (4)
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1. Light
2. Temperature 3. Grazing rates 4. Nutrient loading |
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Trophic cascades
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Effects that top predators have on the plants at the bottom of the food web.
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Sources of carbon for photosynthesis (2)
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1. Atmosphere (very productive lakes)
2. Respiration (mainly allochthonous material) |
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Name the 3 types of rooted macrophytes.
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1. Emergent plants
2. Floating leafed 3. Submerged |
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Name the 4 major groups of macrophytes.
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1. Macrophytic algae
2. Mosses 3. Fern allies 4. Angiosperms |
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heterophylly
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Differences in leaf morphology on a single plant.
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Name the 2 types of nonrooted plants.
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1. Floating
2. Submerged |
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Is transpiration from emergent macrophytes high or low?
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High
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Where do rooted macrophytes gain most of their nutrients? unrooted?
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roots; water
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Name 4 functions of macrophytes in aquatic systems.
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1. Major contributor to primary production
2. Provide habitat 3. Nutrient pumps from sediment 4. Provide substratum for growth of other plants. |
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Marshes
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dominated by emergent aquatic macrophytes (e.g. Typha) and can have some floating or submergent macrophytes. There is a distinct absence of woody plants (trees and shrubs). Peat
accumulation in marshes can be substantial. Marshes have an external water supply such as overflow from rivers or groundwater. |
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Swamp
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contain woody plants such as trees and shrubs. Macrophytes can grow in the open, sunlit areas. Unlike marshes, swamps usually do not accumulate large amounts of peat. Swamps also have an external water supply.
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Bogs
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accumulate peat and the vegetation is dominated by acidophilic mosses and sedges. Trees and
macrophytes are generally rare. Bogs have little or no external inputs of water and are dependent on a high water table that is replenished by rainwater. |
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ombrotrophic
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minerals enter from rainwater
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Fens
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distinguished by mineral-rich
groundwater inputs that result in a higher pH than bogs |
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Minerotrophic
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minerals are loaded via groundwater
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lacunae system
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Hollow spaces in stems and roots allow oxygenation of roots buried in sediments. Only functions in dry season.
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Are most wetlands N or P limited?
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N
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Wetland services to lakes (3)
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1. Nursery habitat for fish
2. Reduce nutrient loading to lakes 3. Provide lakes w/DOC |
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Sediment dating techniques (4)
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1. C14: useful for lakes <40,000 yrs
2. Pb210: useful for lakes <150 yrs old 3. Cs137: useful for lakes <25 yrs old 4. Sediment varves |
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Lotic
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characterized by fast flowing waters
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Lentic
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Characterized by low water velocities
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Freshwater services to humans (3)
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1. Water supply
2. Supply of other goods 3. Instream benefits |
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4 H's (reasons for salmon population decline)
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1. Harvest
2. Habitat degradation 3. Hatchery operations 4. Hydroelectric dams |
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What's wrong with hatcheries (5)
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1. Loss of genetic variability
2. Behavioral differences 3. Ecological effects 4. Overfishing of wild stock 5. Physiological |
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Salmon as ecosystem engineers (4)
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1. Sediment export
2. Nutrient export 3. Algal abundance 4. Insect phenology |
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What controls whether a lake will be acidified? (3)
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1. Hydrogen ion loading w/in a region
2. Buffering capacity of lake 3. Extent of biological alkalinity generation in lake. |
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Chemical effects of increased acidity in aquatic systems (2)
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1. Increased metal solubility
2. Loss of humic DOC |
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Biological effects of increased acidity in aquatic systems (3)
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1. Reproductive failures in fish
2. Fish, zooplankton, and phytoplankton death 3. Food web alterations |
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Biomagnification
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incremental increase in
concentration of a contaminant at each level of a food chain |
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Does lower pH increase or decrease body burden of mercury on fish? Increase in DOC?
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Increase, increase
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How does DOC affect mercury?
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Prevents demethylation of mercury by UV radiation.
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Is methymercury more or less toxic than inorganic mercury?
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More
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Sources of mercury to aquatic systems (2)
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1. Volcanoes
2. Humans |
