Download Nutrient Cycle Imbalances and Climate Change Impacts on Biodiversity and more Exams Human Geography in PDF only on Docsity!
EEB 2100 UConn Exam 2
Most profound nutrients being added to ecosystems by humans - ✔✔Nitrogen and phosphorus Nitrogen facts - ✔✔makes up 78% of Earths atmosphere and many enzymes and proteins that humans need Nitrogen cycle: Fixation - ✔✔Fixation of N2 gas is done by microorganisms using energy to break down the gas into organic NOx compounds(Nitrate and Nitrite) 1/3rd of free-living bacteria(cyanobacteria) conduct fixation 2/3rds of plant-associated bacteria do this as well Nitrogen cycle: Mineralization - ✔✔NOx compounds are converted into NH4+ (ammonium) Organic Nitrogen compounds (NOx) are inaccessible to plants Process done by fungi and bacteria in the soil Nitrogen cycle: Nitrification - ✔✔NH4+ (ammonium) is turn into NOx compounds performed by bacteria to create energy
byproduct of the process is the creation of N2O which is a greenhouse gas that is 300x more effective at warming the earth than carbon dioxide Nitrogen cycle: Denitrification - ✔✔NOx compounds are turned back into nitrogen gas (N2) performed by microbes Anammox Process - ✔✔NH4 + NO2 --> N makes up 30-50% of N2 in oceans Fertilizer and Nitrogen - ✔✔The nitrogen necessary for fertilizer used to be harvested from guano and bird poop Haber-Bosch process - ✔✔Iron catalyst, high temperature and pressure used to break N2 bond to form Ammonia(NH3) Haber-Bosch effects - ✔✔Leads to great acceleration as more fertilizer can be created and used to increase food production. Doubles the amount of people fed per hectare of crop land however, over half of fertilizers used are lost from the land and end up in other places like ponds and streams Green revolution - ✔✔Technologies in 1950s that massively increased global agricultural productivity
Ocean floor is the biggest sink Phosphorus cycle: Phosphate - ✔✔Only Phosphate (PO3) is available to plants Phosphate is assimilated to turn it into organic forms such as ATP Phosphorus cycle: immobilization - ✔✔Phosphorous can become immobilized when bound to rocks and other insolubles Phosphorus cycle: human disturbances - ✔✔Inefficient: only 15-30% of P is taken up by crops and the rest is runoff Wastefulness of food loses 55% more of phosphorus Human sewage inputs 3 MT of P into cycles per year Detergents also used to contain P biome recycling time - ✔✔Nitrogen always cycles faster than Phosphorus and Tropical rainforests have the fastest cycling times, above Temperate deciduous and Boreal forest. Big algae debate - ✔✔was carbon, nitrogen, or phosphorus responsible for algal blooms using experimental lakes it was found that carbon and nitrogen could be added with little to no effect while phosphorus caused major blooms
Cyanobacteria - ✔✔Typical type of algae that bloom during phosphorus additions They are photosynthetic bacteria, some of which are N-fixing when P/N ratio of elements is high they are favored over other types of algae Redfield Ratio - ✔✔Normal ratio of elements in bodies of water Oceans: 106C:16N:1P:16Si Lakes: 400C:30N:1P Lake trophic Status - ✔✔Organizes waterways by how much Chlorophyll-a is present Oligotrophic-Clear blue with almost no algae(Low nutrients, low productivity) Hypereutrophic- green water completely taken over by algae Most lakes in the world are Eutrophic, state before hypereutrophic(high in nutrients and productivity) Algal bloom effects - ✔✔Lots of decomposition of algae requires massive amounts of oxygen to be taken and fish die because of it(fish kills)
Nitrogen is more limiting in oceans hydrologic cycle (water cycle) - ✔✔Solar energy heats up water in oceans and evaporates into clouds Clouds rain down water as precipitation Precipitation that falls on land is either ran off back into oceans or is absorbed by soil to be used by plants or enters groundwater Runoff material - ✔✔Flushes nitrogen and phosphorus into waterways Cropland(most) and urban (second most) areas have a much larger contribution to this effect than forested areas do because forested areas have a really fast recycle rate that keeps nutrients within the ecosystem Fish and HAB - ✔✔Fish are subject to more metabolic stress from rise in water temperature and become more susceptible to HAB(Harmful Algal Blooms). Leach Fields - ✔✔A part of a septic system that can deposit Nitrogen and Phosphorus into waterways because they may not get absorbed before reaching groundwater Nutrients found in local groundwater are main drivers for algal blooms Ocean acidification - ✔✔25% of human generated CO2 is absorbed by oceans
CO2 reacts to form Carbonic acid which lowers ocean PH. This reacts further to form hydrogen atoms that turn the useful carbonate into bicarbonate that marine species dont use. PH has declined by 0.02 units since the 1980's and is projects to decline to 7.7ph by 2 100 Increased CO2 effects on oceans - ✔✔Has indirect effects on sensory organs of fish that dont allow them to migrate properly Stunts growth of Coral reefs Has differing effects on species, leaving some damaged and others unharmed. Fourier Calculation - ✔✔calculated the earths temperature as a rock in space with an energy balance and found that without some sort of atmospheric warming it would be frozen solid Eunice Foote - ✔✔In 1856 through lab experiments, showed that CO and water vapor absorb heat and thus more CO2 in the atmosphere would mean a warmer earth. Roger Ravelle - ✔✔1957: The oceans mixed (surface) layer limits the absorption rate of CO Charles Keeling - ✔✔Discovers steady growing trend of CO2 in the atmosphere, which is now described as the keeling curve. It graphs the ppm of CO2 with respect to time.
Evidence of climate change - ✔✔Pictures of retreating glaciers Temperature change graphs of recorded history(hockey stick) For the entire history of humanoids there has been an ice cap and it is now slowly shrinking GCM- global coupled ocean-atmosphere models - ✔✔represents the climate across the earth and atmosphere using physical, chemical, and ecological processes Ensemble forecasting - ✔✔using multiple models and taking their average in order to predict future climate IPCC reports - ✔✔ 1990 - We need 10 years to be sure 1995 - Large evidence it is human caused 2013 - Extremly likely 2018 - We are screwed Expected Earth temperature rise - ✔✔If we act now- 1 degC If we do nothing- 4 - 5 degC 2 degC is considered catastrophic Why is artic ice warming so much faster than other places on earth - ✔✔White ice melts to reveal darker colored waters that absorb more heat and melt even more ice, creating a snowball effect called Artic Amplification
Albedo - ✔✔Reflectance of a planetary surface Ice has a high albedo and more energy is reflected Dark oceans have a low albedo and more energy is absorbed CT Temperature trends - ✔✔0.3degF/decade winter is warming the fastest because there is less snow on the ground relative to the previous year which leads to more heat absorption during that time of year Expected that we will have the climate that Virginia has now by 2100 Precipitation predictions - ✔✔Northern areas get more precipitation and the dryer areas get less Northern areas get more because the air is colder and colder air cannot hold as much moisture The US is going to get more precipitation and it is going to come in larger downfalls rather than a slow release Sea level rise - ✔✔Half of it is from water expansion- 0.001% increase in volume for an increase in 10 degF but with the amount of water we have on earth this ends up being dramatic other half is from ice melting of Greenland and Antarctic ice sheets NOT SEA ICE. like ice cubes in water, they do not contribute to sea level rise Most extreme models indicate 1m by 2100
Hindcasting - ✔✔Test of a models accuracy by asking it to predict past climate that we have data for and see how close it comes to actual data What are the primary factors influencing climate change - ✔✔Fossil fuel emissions and land use change Biodiversity - ✔✔Short for biological diversity, includes species and genetic variation Diversity - ✔✔The sum of the two categories which are the total number of species(richness) and how evenly distributed species are(abundances) Composition - ✔✔What species we are talking about; ie- endangered species Species of Earth - ✔✔Very difficult to measure but we can estimate 5 +- 3 million, of which 1.5 million have been named. Even still we are losing species before they can be named. Why we care about genetic diversity - ✔✔Some populations of the same species have begun to diverge and are much different now than the original species in terms of genetics Genetic diversity is needed for evolution which is very important in a changing climate Earth's biodiversity - ✔✔Increasing over time with the exception of mass extinction events
Fossil record of marine animals allow us to track this increase Extinction is inevitable - ✔✔4 billion species have evolved over the past 3.5 billion years but 99% of them have become extinct Extinction is balanced by speciation Without threats, species numbers will be random but eventually decline to extinction Previous mass extinction causes - ✔✔Climate change is always involved either as a direct or indirect factor Hothouse to icehouse and vice versa Volcanic eruptions Meteor WWF (World Wildlife Fund) living planet report - ✔✔Documents population trends in about 5000 species and 27,000 populations Has found that since 1970 about 70% of original species are gone Extinction Debt - ✔✔Species that will go extinct without intervention Water in a cracked bowl will continue to leak and eventually be empty
about 1 million species are at risk of extinction and could be up to 8 million based on each taxonomic group Biodiversity Pros - ✔✔More biodiverse systems function better promotes stability and offers buffering during extreme events Ecosystem Services - ✔✔Provision of goods and regulation of environment that benefits humans including: food and freshwater Regulatory effects like erosion control Cultural benefits like tourism and education Ecosystem Functions - ✔✔Basic ecological processes that govern flows of matter, nutrients, and energy through ecosystems influenced directly by global change Depend upon biodiversity Biodiversity experiments - ✔✔Find a consistent pattern of more biodiverse communities being more productive This relationship levels out at high species richness/population Why are more biodiverse communities more productive - ✔✔These communities have a higher chance of including the most productive species(selection effects)
Selection effects - ✔✔Increasing species richness increases the average ecosystem functioning because it is more likely to include higher functioning species Maximization of ecosystem functioning - ✔✔Occurs when the "Best" species is grown on its own. However is has been found that diverse populations outperform the best monoculture and is especially true in the long term Overyielding - ✔✔When a combination of species(polyculture) outperforms the monoculture of the single best species Causes of overyielding - ✔✔Niche Complimentary effects: Different species are better under different conditions Different species are accessing different resources Each species may produce less individually but together produce more than one Facilitation: Species interactions may stimulate better performance(Species A preforms a process which has a byproduct that Species B can use) Portfolio effect(for ecosystems) - ✔✔Fluctuations in multiple species average out Low diversity(single stocks): Productivity is more variable and dips in species can coincide High diversity(mutual funds): Productivity is less variable
Climate velocity - ✔✔the rate and direction that climate shifts across the landscape- for an organism it is how fast do I need to move in order to stay in this climate Climate velocity in mountains and plains - ✔✔Greater climate velocity in plains and lower in mountains Species Range - ✔✔Range of area where species live No-analogue climates - ✔✔new temperature and precipitation patterns never experienced before in history species dispersal - ✔✔Climate change requires a species to disperse well or be well dispersed. Ant-dispersed trees are least dispersed and birds are the most well dispersed Are species tracking climate? - ✔✔yes, but some species may be able to disperse well but rely on a feature that is unmoving phenotypic plasticity - ✔✔Environment dependent response that is non-genetic and very common. Otto and Ewald Phenology - ✔✔timing of life events in species, Great Tit arrives too early due to temperature cue and hatchlings may die from a lack of food because caterpillars rely on a daylight cue Acclimation - ✔✔altering physiology to deal with weather extremes
People in Florida wear coats in 50 degree weather where someone from New England may be in shorts Life history traits - ✔✔Fitness components like survival, reproductive output, and growth species interactions - ✔✔defense, competition, and mutualisms Genetic adaptation - ✔✔Prevents species from being lost to new climates, allows them to adapt very important for species that have low dispersal capacity to track climate Evolution - ✔✔Change in gene frequencies, can be neutral or adaptive Natural selection - ✔✔fitness(survival or reproduction) varies with trait Adaptation - ✔✔Evolutionary change in trait that promotes higher fitness in a particular setting Heritability - ✔✔Proportion of trait variation due to genetics (0-1) Heritability of 1 is all genetics and 0 is all plasticity Extinction - ✔✔Loss of an entire species Extirpation - ✔✔Loss of a population; could lead to extinction but not necessarily
