Ecological Engineering Exam 2
1. What is the difference between a keystone species and a foundation species?
-A keystone Species is an organism that helps define an entire ecosystem. Without a keystone species, an ecosystem would be dramatically different.(apex of the arch) -Foundation Species is used to refer to a species that has a strong role in structuring a community.
Explain why coastal wetlands are able to store lots of carbon in their soils.
-A lot of material that is not able to be decomposed because it is saturated with water so the material is just stuck there. Couple this with high productivity and organic carbon in the system and it doesn't break down very easily. -High productivity and that soils are saturated they are anoxic and it slows down microbial decomposition in the soil.
What are two ways in which the current mass extinction of species differs from earlier mass extinction events?
-A single species, humans drive to extinction and it is characterized primarily by large bodied animals and consumers in particular.
3. What is a trophic cascade and what did Jim Estes measure and where did he measure these variables to assess whether the ecological structure kelp beds in the Aleutian islands was under the control of a trophic cascade?
-A trophic cascade is when an apex predator controls the distribution of resources and they lead to cascades of indirect effects. (Fewer sea otters you have more sea urchins, less kelp) -Jim Estes measured the amount of kelp when he removed sea otters. He found that when they removed sea otters, kelp abundance declined. -Compared two locations, one with a lot of otters and one with a few otters
4. How are the concepts of alternative stable states and hysteresis related? Why is it important for ecosystem managers to be aware of these concepts?
-Alternative Stable State is an event that occurs when perturbations are of a sufficient magnitude and direction that they push an ecosystem from one basin into another. (aka an ecosystem exists under new 'states') -Hysteresis is a changing of the tipping point between ecosystem states depending on the direction of change. Multiple states may persist under equal environmental conditions. -It is important to be able to predict what these systems might do in the future.
Why is BOD removed in wetland treatment systems?
-BOD is the amount of DO needed by aerobic biological organisms to break down organic matter at a certain temperature over a specific time -DO is consumed through the oxidation of organic matter.
What are three approaches to improve infiltration and reduce run-off in urban environment. For each, explain how they work
-Bioretention: recovers storage by infiltration, has an underdrain for low infiltration soils. Plants over a "hallow" ground, when water seeps through the plant roots and soil into the "hallow" ground and purifies water -Permeable Pavements: they are interlocking concrete pavers with multiple layers composed of different materials. Multiple layers of different material to maximize the infiltration -Dry Wells: Runoff stored in void space, slowly percolates into the ground.
What two abiotic drivers create the zonation of species across a salt marsh from the tidal creek into the upland?
-Competition for nitrogen, and flooding
Why does the flow rate in losing streams decrease with distance downstream?
-Flow decreases with distance downstream because of losses to groundwater -This is when the stream is above the water table
Describe how you would collect data to assess whether a wetland treatment system you constructed was working in reducing N and P loads.
-Form of n and p -- relative form such as ammonium, phosphate -Take a water sample to test the inflows outflow. -Aggregate to test the whole system is testing to see if total phosphorus is removed.
Reflection on Tanner Reading -What was the goal of the study? -What were the main findings?
-Goal: Assess effects of plants in horizontal sub-surface flow wetlands -Findings: BOD and COD removal increases with mass loading, however, the presence of plants has little effect on their removal! Because water is below ground, disinfection (removal of fecal bacteria) is low too, a process which requires sunlight (phoytolysis!) driving fluctuations in pH and oxygen demand
2. Explain the Green World Hypothesis, how Robert Paine tested it and what his experiment revealed
-Green World Hypothesis is an idea that 'the world is green' because of predators keep herbivore abundance in check which allow plants to flourish. -Robert Paine tested it by removing Pisaster starfish from rocky shores. He created a food web to see who ate who. He found that Pisaster starfish was at the top of the food chain. He discovered that invertebrate biodiversity plummeted (15 species to 8 to 3) until it ended at a monoculture. One predator can regulate the composition of an entire community. He concluded that the Pisaster starfish are a keystone species.
In terms of CO2 fluxes, define gross primary production, net primary production, and net ecosystem productivity.
-Gross primary Production- CO2 fixed during photosynthesis -Net Primary Production- CO2 fixed - CO2 respired by autotrophs NPP = GPP - R(autotrophs) -Net ecosystem productivity- CO2 Fixed - CO2 respired by all organisms NEP = GPP -(Rautotrophs + Rheteroptrophs)
Why does Odum argue that man and nature are in conflict?
-Humans are in conflict with nature because they attempt to maintain ecosystems in an EARLY successional landscape that exhibit a high production/Biomass efficiency -Nature wants to do the opposite→ a high biomass/production ratio.
Definition of succession
-It is an orderly process of community development that is reasonably directional -It results in modifications of the physical environment: the community itself alters the physical environment (nutrient availability, physical stress)
What are three differences in how nutrient are cycled between early and late successional communities?
-Mineral cycles being open or closed -Nutrient exchange rate between organisms and the environment -Role of detritus in nutrient regeneration
Natural stream vs urban stream
-Natural has lots of leaves, urban has little leaves (shredders) -Natural has little N and P and therefore little algae -Urban has a lot of N and P and therefore a lot of algae (scrappers and gatherers)
Compare and contrast top-down and bottom-up ecosystem controls. Which is more important?
-Nutrients and physical environment driving complexity of food web -Top down: green world -Both of them are very important and act in a dynamic way
What is the P/R, shade amount, primary C source, organic matter texture and primary invertebrate for stream order 12
-P/R: <1 -Shade: high shade -OM texture: ultra fine -Invertebrate: collectors, gatherers, and phytoplankton
What is the P/R, shade amount, primary C source, organic matter texture and primary invertebrate for stream order 1-3
-P/R: <1 -Shade: very narrow, high shade -Primary C: allochthonous -OM texture: coarse -Invertebrate: Shredders
What is the P/R, shade amount, primary C source, organic matter texture and primary invertebrate for stream order 4-6
-P/R: ~1, >1 -Shade: low shade -Primary C: autochthonous -OM texture: fine -Invertebrate: collectors, gatherers, scrapers
Limnetic Zone
-Photic zone -open water -no shading
What is photolysis and how is it related to the performance of wetland treatment systems in breaking down pharmaceuticals?
-Photolysis is process by which we absorb photons. lIght initiating a chemical reaction (ours is sunlight) -Breakdown of pohar(idk what word this is supposed to be) depends on light coming down into system and initiating the reactions. -Wetland treatment systems are cleaning out these pharmaceuticals pollutants. To breakdown these compounds, you need light to to start these reactions.
What are three factors that motivate the increasing use of nature-based coastal defenses?
-Providing coastal protection -Protection through friction and water storage -Provide benefits in fisheries, biodiversity, carbon storage
What are some of the limitations of wetland treatment systems? Under what kind of conditions does it make sense to build them?
-Removal efficiencies and effluent concentrations are dependent on influent concentration and hydraulic loading rate -Space, dont need much land but its energy intensive -Cant be in urban areas because there isnt the land
5. What is meant by 'trophic downgrading of planet Earth'?
-Removing large apex consumers from nature.
Which is an autogenic influence to succession? a. Shading b. Fire c. Nutrient loading d. Hydrology
-Shading: early trees get up and they shade out the environment -autogenic influence: meaning biotic change, succession is organisms that are already there, what is their influence??? Availability of detrital resources
Compare the spatial organization of salt marsh plant communities across inundation gradients under low nutrient and eutrophic (N-enriched) conditions.
-Spatial distribution in salt marsh is determined by competition and flooding. Upper limits of each species set by competition of Nitrogen and lower limits of each species set by flooding -If you increase the Nitrogen in the ecosystem, then there is re-organization of plant communities and expansion of tall species that compete for light with N addition.
What is the difference between synthesis and analysis?
-Synthesis means "to put parts together"... to identify and understand the whole. Synthetic approach (holistic) top down or black box → looking at how they all work together. -Analysis means to "take apart"... to see how things are structured and processed. Analytic approach (reductionist) bottom up or white box -> separating the parts and studying them part by part to see how they work
How are oligotrophic lake and headwater stream similar?
-They are both low productivity environments -Oligotrophic: freshwater and headwater: fresh water -They are both relatively low nutrient systems
What is hydraulic loading rate? What goes into its calculation?
-Used to calculate particle capture -It is the ratio of flow divided by surface area of the wetland
Many rivers are characterized by an annual flood pulse. Name three things these floods transport between the river and floodplain.
-Water and solutes -sediments / OM -Seeds, larvae
Why is succession often considered to be an autogenic process?
-You have organisms that colonize the space first, they change the physical environment in a way that makes it better for other to follow. Without the first introduce of biotic, you get mid successional things, they change the environment that go to a max climax. -The living organisms modify the environment to make it better and benefit the future organism -Species in new communities are in tie replaced by others until the "climax" ecosystem is established
What is the difference between a 0th, 1st and 2nd order chemical reaction?
-Zero order reaction has a rate that is independent of the concentration of the reactants. -First order reaction depends on the concentration of one one reactant -Second Order reaction depends on the concentration of one second order reactant or on two first order reactants.
Climax stages trends
-detrital pathways prevail (lots of internal recycling) -Species interactions become more complex (e.g. plant defenses to grazers, mutualisms)
What are two goals of building retention/detention ponds? Do they typically meet these goals?
-pollutant removal, removing sediment, improve water quality -Holding water so they don't allow streams to have a big surge after rainfall events because of urbanization
Early stages of succession trends
-trophic interactions are simple and fairly linear (e.g. plant-grazer-carnivore) -Tend to be "Green" Food webs (plant based)
Pollutant removal in wetlands is most often modeled as a ____-order decay.
1st
Life span of early successional species is (</>) than late successional species
<
Size of early successional species is (</>) than late successional species
<
Growth rate of early successional species is (</>) than late successional species
>
Number of seeds of early successional species is (</>) than late successional species
>
What important process occurs in the photic limnetic zone? What organisms are responsible for this process?
A lot of productivity driven by phytoplankton
Describe changes in runoff, infiltration, and ET as watershed impervious cover goes up.
As impervious cover goes up, runoff is dramatically increased while infiltration and evapotranspiration decreases.
What do shredders eat
CPOM (coarse particulate organic matter)
Which of the following ecosystem services results from P/R>1? Meaning need R to be more than P a. Denitrification b. Carbon sequestration c. Flood abatement d. Groundwater recharge
Carbon sequestration
What 1972 legislation regulates discharge of pollutants to water bodies?
Clean Water Act
Why is sediment delivery important to the vertical accretion and lateral expansion of coastal wetlands?
Coastal wetlands are biogenically formed. The marsh land is only there because the plants built the land form. The plants trap sediments and lay down organic material. Sediment gets trapped on platform of marsh (vertical) and gets trapped on edges. You need sediment to stimulate biogenic (biological process) habitat formation
Shallow lakes: a. Have large limnetic zones b. Are strongly stratified in winter c. Are always oligotrophic d. Are usually polymictic
D. Are usually polymictic: numerous/continuous mixing, shallow, lots of wind -shallow lakes have no limnetic zones
Why are there fewer organisms at higher trophic levels?
Energy and food availability decreases with the higher trophic levels
T/F: Forests are equally distributed across the globe
F
T/F: Headwater streams have high productivity
F
T/F: Succession tends to be a disorderly process
F
T/F: The estuarine environment includes all tidally influenced areas.
F
T/F: The majority of lakes in the world are large (>10 km2)
F
T/F: To be a wetland, an area must be inundated (covered with water)
F
T/F: von Bertalanffy said that the physicists assumption of closed systems was possible
F
T/F:Salinity levels are very stable in estuaries
F
T/F: The Sweetwater Wetlands in Gainesville is an example of a sub-surface flow wetland treatment system
F: horizontal
T/F: Wetlands are good at storing carbon because their soils are aerobic
F: they are anaerobic
What do collectors eat
FPOM (fine particulate organic matter)
What do gatherers eat
FPOM off algae
Losing Stream
Flow decreases with distance downstream because of losses to Gw (water table is below stream)
List three elements of low impact development site design
Greenroofs, Cisterns, Permeable Pavements
Which of the following describes a river or stream that only has seasonal flows? a. Intermittent b. Perennial c. Ephemeral d. Wash
Intermittent
What is ecological restoration?
Is the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed
In "classical" succession, what is the ultimate (final, eventual) ecosystem state called?
Mature climax ecosystem
What limits the geographic extent of mangrove systems a. Competition b. Temperature c. Nutrients d. Herbivory
Nutrients
How are high-order streams and shallow lakes similar?
Open water streams have more light availability, and so does a shallow lake therefor high productivity in both
Which of the following is abundant at the bottom of a stratified lake and scarce at the top? a. Oxygen b. CO2 c. Phytoplankton d. Heat
Phytoplankton
Circle one: Where is oxygen highest during the day? Littoral Zone or Limnetic Zone
Plants and algae produce oxygen through photosynthesis, availability of oxygen during day time, there is no shading therefore there is a lot of photosynthesis going on during the day in the limnetic zone (open area, no shading)
List 2 ways early-successional species facilitate the establishment of climax species.
Production, growth, and quantity
Explain why the presence of plants may have a stronger effect on N-removal than BOD removal in sub-surface flow wetlands (from Tanner reading)
Promoting transformations to gaseous forms and sequestration in accumulating organic matter.
How does temperature affect pollutant removal?
Seasonal! (Like the wetland lab we did)
what is classical succession?
Species in new communities are in time replaced by others until the climax ecosystem is established
Explain how species richness and species evenness tend to change as succession proceeds.
Species richness tends to increase nd level off with succession Species evenness start very low because few, rapidly growing species dominate and increases with succession.
T/F: Modeling is both analytic and synthetic at the same time
T
T/F: Residential flooding tends to increase with increasing impervious cover
T
T/F: Succession results in a community that exhibits maximum biomass
T
T/F: The majority of all stream miles are made up of first-order streams
T
Why do lakes in temperate climates turn over twice per year?
The lake is stratified in warm months. Autumn cooling causes upper water to sink, displacing lower water. In spring, the water mixes again due to ice melt.
Summarize the flood pulse concept in one sentence.
Theory that the annual flood pulse is the most important structuring event and biologically productive feature of a river ecosystem→ it is a natural function of replenishment
River Continuum Concept
a watercourse is an open ecosystem that is in constant interaction with the bank, moving from source to mouth, constantly changing.
What do scrapers eat
algae
Gaining Streams
flow increases with distance downstream because of gain from GW (water table is higher than stream)
Littoral Zone
from shore to 2m or to extent of emerging plants (this is more shaded)
Perennial stream
has flow year round, typically gaining stream
Dissolved oxygen levels in a lake is typically _________ during the day and ________ during the night, because of autotrophic growth during sunlit hours and respiration during day and night.
higher, lower
The _______ zone is where rooted, emergent plants occur in lake ecosystems.
littoral
Ephemeral Stream
only flows for a short periods after a rain event. Stream bed is typically higher than water table
What are 5 critical variables that control the rate at which pharmaceuticals are broken down in wetland treatment systems?
pH, temperature, Dissolved Oxygen, Depth of water, NOM Concentration
what is apex predator?
predator at the top of the food chain upon which no other species' preys
what is trophic cascade?
propagation of impacts by consumers on their prey downward through the food web
Intermittent stream
seasonal, consistent flow when gaining stream but then transitions to no flow when losing stream during the dry season
Annual food pulse
the most important structuring event and biologically productive feature of a river ecosystem. Describes the movement, distribution and quality of water in river ecosystems and the dynamic interaction between water and land
Nutrient Loading
think about it being a human drive influence
What is modeling
using both synthesis and analysis approach at the same time
Hydrology
velocity, shear stress, residence time, mixing
Lakes in Florida are typically too ____________ for stratification to occur.
warm and shallow
Shade tolerance of early successional species is (</>) than late successional species
we dont know this one!!