group discussed during synchronous – My Assignment Tutor

Example questions with answersThese examples are drawn from the lists of questions for each topic that I have provided andthat the group discussed during synchronous sessions in September. The approach I willdescribe here should serve as a very general template for how to approach many otherquestions.That template has some common characteristics:1. Identify the main concept2. Demonstrate that you understand the main concept by explaining it clearly.3. Proceed with answering the specifics of the question (e.g. by explaining how theconcept applies to a particular example, or by working through a quantitativeproblem).There is no single formula that can apply to every possible question. However, the basicpurpose of exams is to encourage learning. The way we mark exams is to ask whether you havedemonstrated that learning. Please keep in mind that if you did not demonstrate understandingthoroughly, then you have not answered the question being asked.Simple questions would have less weight in terms of marks. Complex, longer questions wouldhave greater weight. It is ALWAYS necessary for you to demonstrate that you did the work, soshowing your reasoning and every step is vital.Topic 1, question 2:• Discuss the global biogeochemical cycle for carbon, including a major carbon sink and amajor carbon source. Describe seasonal patterns in carbon sinks/absorption. (this questionis quite simple in terms of describing ecological processes in comparison with things cominglater in the course)Carbon cycles continuously between the atmosphere and ecosystems. A major “sink” forcarbon (a sink is where something is stored in large quantities) is vegetation. In spring, rapidgrowth of leaves pulls a very large amount of carbon dioxide out of the atmosphere and intovegetation. A major carbon source is fire, which can release large amounts of carbon fromburned areas. Seasonally, spring “green up” of vegetation is cyclical with loss of dead leavesfrom vegetation in the fall, so carbon is absorbed and then released seasonally throughvegetation green up and senescence.Topic 2, question 8:• Propose and explain a prediction of the hypothesis that carbon dioxide contributes to globalwarming. Discuss a way to test this hypothesis.A hypothesis is a general statement for how something works. It must be testable in some way.In other words, it must be able to generate predictions that data could show to be false. Aprediction that is falsified shows that the hypothesis is also false (in idealized, philosophicalterms). A hypothesis that is shown to be wrong as stated might be modified to account for newobservations, so understanding tends to grow over time. A hypothesis regarding carbon dioxideand temperature warming: Carbon dioxide absorbs infrared radiation and therefore traps heatin the atmosphere. A prediction of this hypothesis is that differences in atmospheric carbondioxide should relate to differences in average temperature over time. A way to test thisprediction would be examine the historical record of carbon dioxide in the atmosphere and tomeasure whether changing CO2 concentrations were related to temperature change.Topic 3, question 3:• How can biomass measurements be relevant to harvesting of a resource? Provide andexplain specific examples. (this question is also quite light on process-level understanding)Biomass is the amount of material in an area that is a product of organismal growth. Harvestinga resource needs to account for understanding of how much of that resource is actuallypresent. Knowledge of biomass of species like cod should inform the size of the fishery that ispermitted over a particular time period. If biomass is removed from that resource at too great arate, then the resource will become smaller over time. In this example, the cod stock couldcollapse (as has actually happened in areas around Canada). A second example could be in theform of forestry: measured amounts of harvestable biomass in forests help determine howmuch logging can take place in a given area. As with cod, removal of too much biomassdiminishes the resources and represents unsustainable harvesting efforts.Topic 4, question 4:• Explain the potential roles of three limiting factors for net primary productivity and whythese factors could be altered directly by climate change.Net primary productivity is the assimilation of carbon into plant biomass after accounting forrespiration. Across broad areas, NPP is limited by incident radiation (sunlight), wateravailability, and heat. In areas that are particularly cloudy, less sunlight is available to drivephotosynthesis. Water availability and heat can also both limit how quickly plants canphotosynthesize. Climate change will change all three of these factors. Areas that are currentlylimited by any or all of these factors could see the availability of these factors increase, withconsequent growth in NPP. The opposite is also possible: if areas become drier, for example,new limitations on NPP could be created that will reduce NPP in that area.Topic 6, question 4 (I wanted to include a quantitative question in the list of examples):• Light intensity at the surface of a lake is 240 J/m2s. 35% of the light at the surface of the lakeis lost through 1 metre of depth. What is the light intensity at 10 metres? Describe theimpacts of this light intensity gradients on the capacity of macrophyte growth in shallowwaters at the shore in comparison with deeper areas. Create a graph showing the pattern oflight intensity decline in this lake showing light intensities at the surface, at 2 metres depth,5 metres depth, and 10 metres depth.Light is absorbed by water and materials in water and therefore light becomes less available forphotosynthesis with increasing depth. The relationship between light intensity and depth inwater depends on this equation:𝑑𝐼𝑑𝑍 = -𝑘𝑍The rate of change of light intensity is dependent on water clarity (captured by the k, thecoefficient of light attenuation, m-1) and how deep the measurement is taken (Z, m). Afterintegrating and linearizing this equation, it is easier to work with:ln⁡(𝐼𝑍) = ln⁡(𝐼0) – 𝑘𝑍where Iz is light intensity at depth Z and I0 is light intensity at the surface (depth, Z = 0m).The question gives all pertinent values.I0=240 J/m2sk = 0.35 (because 35% of light is lost per metre).Z = 10m.So, ln(IZ) = ln(320) – (0.35)(10)ln(IZ) = 2.27So, light intensity at a depth of 10m, I10, is 9.66 J/m2s (remember to use inverse of ln oncalculators, usually shown as “ex” to calculate the inverse natural log of 2.27.It is easy to create a simple graph of light intensities relative to depth, measured at depths of 0,2, 5, and 10m.Same calculations for each of 2 and 5m depths.Light intensity at 2m:ln(IZ) = ln(320) – (0.35)(2)ln(IZ) = 5.07I2 = 158.91 J/m2sLight intensity at 5m:ln(IZ) = ln(320) – (0.35)(5)ln(IZ) = 4.02I5 = 55.61 J/m2sMake a graph:Outline● What is Ecology and why this science?● ecology and environmentalism are not the same thing● ecology is a science, NOT a cause, ideology, or political affiliationecology​: the scientific study of the distribution and abundance of species● we need to discover general rules in nature● general understanding is what drives ecologists● we must focus on key ecological patternswhy ecology?● critical problems are very easy to find nowadays○ i.e. sea level rise, habitat loss, overfishing, etc.○The science of ecology seeks to solve problems that range in scope from microscopic to global.­ What causes certain environments to be favorable to certain animals? ­Fragmented landscape studiesThe big pictureLife is very diverse in some environments, and very sparse in others.­ Why do certain patterns arise? Why do they persist through time?­­­Diversity and its maintenanceBiodiversity will be much greater when the environment is tropicalHot and wet ­ Aspects of climate are dominant forcesCarbon cycle​: the planet “breathing”­ Trees, plants, breath in and out­ Carbon moves around­ Carbon is moved in and out of terrestrial ecosystemsAbiotic factors can exert strong effects on species distribution and abundance.­ Water availability, landscape, etc.Biotic factors can also affect species’ distribution and abundance:find more resources at oneclass.comfind more resources at ­i.e. the american chestnut tree were nearly all killed by a parasitic chestnut blight­ An invasive pathogen fundamentally changed the structure of north american deciduous forests­ This also had a huge effect on bird and mammal diversity­ Our understanding on what is “normal” is based on what we grew up with → buthistorically speaking, chestnut trees should be more common than dandelions­ Our baseline shiftsOther interspecific interactions include mutualism, competition, predation, etc.­ Some interactions are not harmful (Mutualism: benefits both parties, i.e. bees andflowers)Interactions between species can also be negative:­ i.e. poison ivy and peopleEcology also includes the study of dynamics of populations­ Why do populations sometimes increase or disappear drastically?Human activities cause virtually all present­day extinctions ­Extinctions are now occurring at a pace comparable to that last seen at the end of theage of the dinosaurs One role of ecology is to provide scientific underpinnings for conservation activities.This requires knowledge of different forms of natural and anthropogenic change (i.e.disturbance from human and natural sources, and succession)The loss of species is not only an ethical dilemma, but a practical one­ Species in ecosystems contribute to ecosystem functions and services that are criticalfor the human enterprise ­Even uncommon species can exude great effects, that appear to be disproportionate tothe ratio of them to other species find more resources at oneclass.comfind more resources at oneclass.comThe Carbon Cycle­ A very important part of releasing carbon back into the atmosphere is ​fireTo encourage grazing in parks (the serengeti) but also to encourage grazing in animals thatbenefit humans (like cows)Loss of species is a ​practical ​ dilemma­ Species in ecosystems all contribute to an ecosystem’s functions and services that arecritical (even rare species) i.e. lions are not as common as gazelles, but they provide acrucial part of the ecosystemEcosystem functions:​ the biophysical processes of an ecosystem­ Ecosystem services:​ When these functions benefit humans (i.e. pollination ­introducing a species of bees into an ecosystem can in turn cause plants to grow ­humans manipulate ecosystems on purpose for their own benefit)­ There are many ways in which ecosystem functions can be seen as services­ Unfortunately, species required for ecosystem services are being lost rapidly withclimate change impacts → bumblebee population extinctions in southern areas &low elevations­ When environmental change renders an environment inhospitable to a species,the functions and services will diminish and disappear ­Bumblebee species have unusually sensitive distributions and reactions toenvironmental changes ­ Climate change causes their environments to be too hot → their distributions areretreating (from low elevations & latitudes)Ecosystems are responsible for: ­Flood control­ Coastal wetlands buffer against extreme flooding → a tsunami’s energy will bedissipated by these wetlands → less human casualtiesBuilding wetlands → the benefits of the ecosystem service from the coastal­ wetlands are enormous­ Soil creation­ Soil = the medium in which things will grow (not dirt!)­ Soil contains a ton of bacteria, fungus, etc → they cycle nutrients­ The absence of soil… nothing will grow­ Soil creation and conservation → if you don’t do this, agriculture is not a thing ­Regulation of the hydrological cycle­ Atmospheric regulation­ Climatic regulation­High biomass areas (vegetation, etc) create their own climate­­Provision of renewable resourcesPollination find more resources at oneclass.comfind more resources at● The costs are extremely high● The human economy rests on ecosystem services in a provisional and global sense● We can’t replace these things● Ecosystem services → worth $33 TRILLION → twice the value of the world’s economy(1997)SummaryThere are many important ecological problems. We must understand these issues. Theproblems range from purely scientific, to entirely applied. Ecological discoveries can exertmassive societal influences.find more resources at oneclass.comfind more resources at oneclass.comWhat is science?­ What do scientists try to do?­ Is there a method for good science?­ What distinguishes the scientific perspective from other ways of knowing the world? ­Philosophies are shared across the sciencesPlato & Aristotle­Plato ­ the world of forms, the stars the skies, not things you can touch, plato believesyou can purely reason and find the answers ­ Aristotle ­ the world around him, the world had to be experienced and measured, youcan’t understand the world through pure reason, how have to actually make ameasurement, get out thereScientific Method1) Define a question­ That can be answered → must have a testable response­ That pushed the boundaries of knowledge (something we haven’t thought ofbefore), a new idea!­ That is interesting → people need to care what the answer is ­Important questions come from curiosity2) Hypotheses→ Hypothesis 1, Hypothesis 2, Hypothesis 3, etc.­­i.e. H1 = sun revolves around the earth… H2 = earth revolves around the sunHypotheses come from observation­Induction­ Specific observation from which we extrapolate to a general rule­ Generalizations → i.e. it is cloud, therefore it will rain­ Generalization is not always beneficial ​​ ​ ­ Inductive reasoning = argues from the specific to the general ­Unreliable!!!­Hypotheses originate from imagination and intuition ​­ “Imagination is more important than knowledge”​ ­ Albert Einstein­ Thinking differently about things allows us to push the boundaries of science3) Predictions­ What do you think the result will be once you test your hypothesis? ­­­­Testable predictionsMultiple predictions to one hypothesisUnique predictions to each hypothesisWhere do predictions come from?­For a hypothesis to be testable, it must make predictions that can berefuted find more resources at oneclass.comfind more resources at ­Distinguishing between hypotheses requires mutually exclusivepredictions 4) Observations­ True, uncertain, false5) Conclusions­ Eliminate false hypothesesTests­ deductive reasoning ​ ​ is used to identify what ​should be observed, if the hypothesis isactually correct ­if your hypothesis is correct, you can make a prediction based on what you have proven­ e.g. climate change results from CO2 change … therefore temperature will rise ifCO2 rises­BUT we must be careful with deductive reasoning­­If hypothesis is true, then a prediction derived from the hypothesis is trueBUT it does not mean that if the prediction is true, the hypothesis is trueDeductive reasoning flows one way only ● The process of generating new scientific understanding is not as simple as aphilosophical abstraction● There is always a possibility for a theory to be superseded by something that allows useven more understanding● Every Time we do anything, we practice the science method, all the time­ Making predictions, testing our truths, etc.e.g. ​Cholera in the 19th century­ What causes cholera?­ Nobody knew what it was, no one knew what microorganisms were back then, theyknew there were very small things, but the link between microorganisms and humanillness/health had not been made­ A doctor figured that it had to do with something being in the water → this doctorconvinced city authorities that they should take the handle off the well, so that the pumpcouldn’t be used → the cholera cases stopped!­ The water supply in some way was at cause for the cholera­ No one knew it was because of the bacteria, they just made a correlation­ They did the experiment (took the handle off the well) to see if it made a difference­ This is how they realized something in the water was doing this­ This started conversations about sewage → the city was really gross, no sewagetreatment, contaminated air and water, a bad urban condition­ Joseph Bazalgette constructed an effective sewer system in Londone.g. ​Eutrophicationfind more resources at oneclass.comfind more resources at­ What determines phytoplankton abundance? ­Let’s make this question operational … scientiful­ What distinguishes lakes that are chlorophyll­rich from lakes that are chlorophyll­poor­Make a general statement, and derive predictions­­­Hypothesis:Predictions:If you manipulate the conditions in one environment and observe a response,­ They stuck an impermeable barrier (nothing can flow across)­ They added N, C and P to one side of the lake, and raised the concentration ofthese three ​​­ To the other side, they added N and C, raising the concentration to an identicallevel­ The only difference was the phosphorous­ One side turned into an algae filled swamp (the P side)­ This showed that you could assume Phosphorous was contributing to algalbodies growing­ This changed the way we thought about water quality ­­By releasing P into aquatic ecosystems, we were changing the water qualityPhosphorous content has been dramatically reduced in detergents and other things,because of this experiment Balancing realism and simplicity­ Always choose the simplest prediction­ This is known as the law of ​parsimony­ Simpler hypothesis are better­ When one hypothesis can predict multiple phenomena, it’s better than multiple, uniquehypotheses ­“Everything should be made as simple as possible, but not simpler” ­ Albert EinsteinEcological systems sometimes defy simple explanation­In real systems, there are many constituents, interactions, and effects ­ The real cause of a phenomenon cannot always be identified­ Species don’t always behave in a predictable fashion, like atoms and subatomic particlesdo ­Hypotheses can sometimes be very complicatedComplex ecological systems­Predictive power is the strongest evidence that natural sciences have an objective gripon reality ­ The way to know if predictions are credible has to do with whether or not what youobserve in nature is predictablefind more resources at oneclass.comfind more resources at oneclass.comAbundance of Species­ Very abundant species affect the ecosystem­ e.g. There is a hyperabundance white tailed deers → they eat everything­ Not much will grow → they ruin the landscape­ If you want to conserve plant populations, this is a problem­ e.g. an abundance of disease vectors like ticks → lyme disease, rocky mountainspotted fever­ e.g. mountain pine beetles, eat lodgepole pine­ These beetles thrived so much because there was so much lodgepolepine­ The beetles destroyed everything­ To fix this, a more diverse forest → beetles can’t kill everythingSpatial distribution of a species ­­Economic consequenceIntroducing one species can change spatial distribution, and cause massiveconsequences for other species in that environment Factors that can influence ecological characteristicsHistory, evolution­ What happened historically that changed the trajectory of an ecological community?­ Past evolutionary processes­ There are barriers to dispersal → some species never make it any further than a certainpoint­ e.g. kangaroos couldn’t pass the “wallace line” (the gap between islands withdeep water) ­Marsupials make it to the boundary of this line and no further­ The ice ageEvolution commonly operates over long time periods, many generations­­ Slow change on ecological time scales­Exception: organisms that reproduce very quickly (antibiotic resistance in bacteria)­ Dispersal­Post glacial: the colonisation of areas are important for structuring ecologicalcommunities → what kind of species you will find in certain areasHuman­caused climate change: the geographical ranges of species have begunto shift in huge ways → we study this using historical analogs­ Physiological tolerance­ The ecological niche­ The totality of environmental conditions that a species can tolerate­ Where you can find a species is defined by which conditions it can withstand­ Organisms can evolve to gain physiological tolerance to different environmentsover timefind more resources at oneclass.comfind more resources at­ The ecological niche is an ​ ​n­dimensional hypervolume that defines where aspecies could persist ­Physiological tolerance influences geographic range enormously­ e.g. Coral reefs are dying very fast, due to the heat this year ­ The oceans in places where there are coral reefs are as hot as they haveever seen to be­ The coral species are undergoing thermal stressLimiting Resources ­­Resources: a factor that is essential for individual growth (nutrients, light, water, space)Liebig’s law of the minimum: you have to have more of the thing that holds you back ifyou’re going to grow more­ The law of the minimum: the limiting factor is the one that an organism must concentratethe most relative to environmentalRatio = the amount required / the amount available­ Biotic interactions­ One organism and another affect each other­ Competition ­­PredatoryBeneficial­ Trophic interactions = herbivory and carnivory (predation)­ The fundamental niche relative to the realized niche­ A species can exclude another from part or all of its fundamental niche­Realized niche adds in biotic interactions Trophic interactionsPredation: one animal eating anotherHerbivory: an animal eating a plant­ These interactions have massive effects on the distribution and abundance of species­ Structure of the ecosystem differs­ There is a less complex structure when there are elk; since they kill all the plants­ When you change the distributions of species of an ecosystem, you change theirfunctions­ Their ability to retain carbonfind more resources at oneclass.comfind more resources at oneclass.comMajor physical properties of terrestrial ecosystems– Climate– Water– Nutrients– SubstrateClimateSolar radiation​: radiant energy emitted by the sun, particularly electromagnetic energy– at top of atmosphere, maximized at 0​o​ latitude– As hot air rises, it loses its heat, and its capacity to hold onto water– If the warm air rises over oceans, or over land masses where there is water around, itmoves a lot of water into the atmosphere where the air cools off, and createsprecipitation– This creates a rich biotic environment, where the rain falls– The water spreads out, and the air column has become cooler in the upper atmosphere,begins to have higher densities, sinks back into the ground– When the air comes back down the water is released, and as it reaches the ground itlacks moisture → deserts** all this time the water is moving away from the oceans/equator**Coriolis effect– Differential rotation velocity at different parts of the earth– Coriolis effect causes apparent deflection of winds clockwise in the Northern hemisphereand counterclockwise in the Southern hemisphere– The air moves from a part of the earth that is spinning faster to a part of the earth that isappearing to spin slower– At the equator → winds come from the east– At the south pole → winds come from the westfind more resources at oneclass.comfind more resources at oneclass.comCoriolis effectfind more resources at oneclass.comfind more resources at oneclass.comClimate – global scale– Incident solar radiation at the earth’s surface– A little to the north/a little to the south of the equator are the world’s biggest deserts– This is because solar radiation is maximal around 30​o​ N and 30​o​ SAdvection of heatTransfer of heat in a fluid– Ocean currents, atmospheric circulation– The atmosphere and oceans move heat around advectively → because they are fluidsVariables integrating energy:– Temperature– Potential evapotranspirationGlobal Climate● The difference between annual maximum temperature and minimum temperature○ The hottest temp. Observed in every pixel and subtracting from it the coldesttemp.○ Large difference = red○ Lowest difference = dark blue● Species must have strategies to survive differences in seasonality (a difference of 70​o​Cover the course of a year, for example) → they must adapt● Climate is huge in understanding where species are found● What are the strategies of species for coping?● As the extremes begin to change, so does the distribution of species● Advection causes these temperatures to change in ways that are really importantfind more resources at oneclass.comfind more resources at oneclass.comClimate – regional effectsPrecipitation– Orographic effects​: mountain ranges impose differences in terms of precipitations– Movement of air across those surfaces– Warm air can hold a lot of water, cold air cannot– Winds travelling inland from the coast lose huge amounts of moisture andbecome drier– Air moving in from the oceans has a lot of water– The air rises over the surfaces of those mountains– It loses its heat– It loses its ability to hold large amounts of water– We end up with high biomass vegetation in the areas where it rains a lot– Coastal temperate rainforests● As you move further inland, the air continues● At this point it has lost all of its water● At the inner boundaries of these mountain ranges, we get the desert● The air that blows in is very dry at this point, past the mountains● Very small geographical gradient, but very large difference in climateClimate diagrams– Summarize climatic information using a standardized structure– Temperature plotted on left vertical axis– Precipitation plotted on right vertical axis– 10​o​C equivalent to 20mm when plotting– Relative position of lines reflect water availability– Adequate moisture for plant growth when precipitation above temperature– Water deficit and temperature require organismal tolerance, and therefore, affect biome,habitat, and speciesAgricultureWhat is the likelihood that certain forms of agriculture will be sustainable?– We need the right kinds of soils– Can we convert other parts of the world to agriculturally useful land?– Maps can help reflect agricultural potential and nutrient presence– We need to take into account other things as well thoughfind more resources at oneclass.comfind more resources at oneclass.comNutrients● Poor soils are commonly in○ Tropics (iron-rich)○ Regions with underlying insoluble rocks (e.g. granite)– Granitic rock = the rate at which nutrients are weathered into the soil islow, which makes for poor growing conditions– Source of high quality of nutrients missing? Carnivorous plants● Rich soils are commonly in○ Regions with underlying soluble rocks (e.g. sedimentary rock)○ The rate at which nutrients can be replenished = high○ Increased reliance on nodules on the roots → N-fixing bacteriaGeographical distribution of factors limiting primary productivity– How efficiently can ecosystems fix carbon out of the atmosphere? (aka how green is theenvironment)– In these systems, what are the limitations on plant growth– There are 3 factors that decide productivity in an ecosystem:1) Temperature2) Radiation3) Water availability– We can measure these factors in relation to productivity, and determine what allowscarbon to be fixed out of the atmosphere– Depending on where you are on earth, different factors limit primary productivity and rateof photosynthesis of plantsfind more resources at oneclass.comfind more resources at oneclass.comWhat are the consequences of climate change on these gradients of limitation– When you change climatic conditions, you change the limiting factor of primaryproductivityLimitations can become extremely pronounced– Seedlings in large canopy redwood forests can’t grow beyond a certain size becausethey get no sunlight → they require a lot of photosynthesis to develop a large biomassPhysical factors at a local scale– The slope of an environment– Substrate → in a bog, for example, water flows in, but not outfind more resources at oneclass.comfind more resources at oneclass.comBiological Consequences of physical factors– Spatial distribution of organisms– Primary productivity– BiodiversitySpatial distribution of species– Biomes, at a large scale– Species associated with specific ecosystem characteristics, at a small scaleHoldridge life zonesCanadian ecozones– Based on geological and biological characteristics– Divides everything up into 15 ecozones– Ecoregions: subdivisions of ecozones → more precise– Ecodistricts: subdivision of ecoregionsBiome – Mixedwood Plains– Smallest ecozone– Highest biological diversity– Faces the most extreme threats– Highest population density– Soil properties are very favorable for agriculture– Some of canada’s most fertile landscapes– Mesic habitat​: not too wet, not too dryfind more resources at oneclass.comfind more resources at– Mostly deciduous; oaks, beech, maples– Some conifers; hemlock, white pine– Relatively dark understory → dense forest canopy– No large forests, or continuous habitat left… due to intensive agriculture and forestry– Biodiversity hotspot, but lots of threatened species due to humansBiome – Boreal ecosystems– Strongly granitic substrate (precambrian)– Soils are very nutrient poor, bad drainage (lots of bogs) and landscapes shaped byrepeated glaciation– Climate is colder, and drier– Boreal shield → internal continental conditions → tend to be drier than the coastalconditions– These areas, in summer, dry + warm = a higher likelihood of major disturbancesand forest fires– Highest biodiversity is found where there has been a disturbance– Typical vegetation = conifers (fir, spruce, jack pine) and deciduous (birch, aspen)Terrestrial primary productivity – global– Evapotranspiration integrates temperature and precipitationRegional primary productivity– What soils are underneath → substrate– Humans affect it as wellLocal primary productivity– Sunward facing slopes get more sun; hotter; drier; different community composition (thisis a microclimate)– Proximity to water – vegetation closer to water changes– Boreal shield – the substrate, geological composition** think about what drives productivity ** → question on an examTrophic Status– Concentration of nutrients– Oligotrophic: beautiful crystal clear, not productive– Mesotrophic: more elements to it, cattails, etc.– Eutrophic: lots of green, stuff everywhere, not nice to swim in, super productiveWhat changes productivity in lakes?– Differences in nutrientsfind more resources at oneclass.comfind more resources at Lake TypeNutrient concentration (P, N)oligotrophiclowmesotrophicmediumeutrophichigh What affects levels of nutrients?1. Substrate (non-point source)2. Water use (point source)Thermal stratification– Lakes mixing– Hypolimnion: cold bottom water – dense– Epilimnion: upper layerSource of oxygen in a lake: photosynthesis,What takes oxygen away: respirationOxygen: vertical oxygen profilefind more resources at oneclass.comfind more resources at oneclass.comVertical total [P] concentration profilesfind more resources at oneclass.comfind more resources at


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