Curse Environmental 101 Dr James The Nature of Environmental Science 9 5 environment surroundings multiple component system natural and built with 1 part dynamic flows between components of systems and between systems abrupt interfaces between two faces Dominant Environmental Systems sand seawater air and insects Important concepts dynamic change and flow across interfaces cycling FINISHHH Environmental systems flows across interfaces and scales zones of abrupt FINISHH molecular cellular organism global Feedback systems controlling system balance and stability human sweating as a kind of feedback Negative feedback system is stabilized by counteracting response to perturbation i e warming leads to cooling self correcting 9 8 insects have 8 8 millions different species way more than mammals or others interfaces are usually between different phases ie Solids and liquids As the Arctic Ocean warms megatonnes of methane trapped in melting ice cages bubble up from ocean floor methane absorbs heat emitted from the earth into atmosphere feedback Positive Positive feedback system condition is reinforced ie Warming leads to more warming self exacerbating Methane Hydrate based ecosystem on ocean floor methane formation from microbe decomposition of original matter melting releases methane nourishes microbes FINISHHHH negative feedback tends to syabilize a system beneficial positive feedback tends to destablilize a system not usually beneficial Environmental Systems Summary complex composed of interconnected sub units interfaces between the units material and energy flows occur feedback systems operate negative and positive stabilize or destabilize systems Biosphere atmosphere ecosphere hydrosphere lithosphere Science of the Environment holistic takes everything together multi disciplinary directs applications to human nature relationships policy and ethics used to be viewed as descriptive and value laden view has changed in recent decades Empirical Investigations observe and experiment on something and collect data to make hypothesis Inductive reasoning from specific to general predicting system behavior or a cause effect relationship often with if then statement observe or measure that CO2 levels have increased in the atmosphere and that temps are rising slowly Data leads to a tentative hypothesis or generalization that CO2 is responsible for global warming Deductive reasoning from general to specific IF this hypothesis is true THEN decreasing CO2 emissions will mitigate global warming could be tested experimentally could falsify this hypothesis leads to proof without absolute certainty Nature of good hypotheses some basis in current scientific understanding logical clear concise can test with observations or experiments can be falsified from scientists ideas world view observed patterns in nature if it survives many attempts to falsify with observation and experimentation then it becomes provisionally accepted Can lead to a theory a well tested explanation 9 10 Theory hypothesis that has been tested and is most likely the truth exploration and survey important discovery of phenomena interfaces relationships can be creative and exciting often a first step in environmental science Sources of uncertainty precision reproducibility of replicated data ex pH 4 5 4 7 4 9 for 3 water samples form Cranberry Lake in the Adirondack Mts mean 4 7 high precision values are close to one another can be quantified with standard deviation low in this case 2 Low precision poor reproductbility ex pH 3 5 4 7 5 9 for 3 water samples from Sagamore Lake mean 4 7 low precision values are not close to one another standard deviation 1 2 not as close as the previous example Accuracy is not the same as precision accuracy closeness of measured value to true value measured pH 4 7 actual 5 7 poor accuracy measured pH 4 7 actual 4 8 high accuracy measurements can be precise but not accurate Other uncertainties in environmental science data quality and relevance alternative hypotheses and explanations temporal and spatial variability reliability of predictive computer models based on available data identification of cause effect relationship correlation is not causation 9 12 C N cycles and systems Molecular scale C N cycles Biomes or Eco regions vegetative communities on global scale governed climate topography and soil conditions Cyanobacteria blue green algae and Calcite crystals they fix CO2 to sugars photosynthesis they fix N2 to NH4 nitrogen fixation they form CaCO3 in same environment mineral formation Photosynthesis enzymatic needs sunlight reduction of CO2 O2 evolved from H2O 9 15 OMR how does agriculture co opt the C cycle What is lactic acid anything that goes sour produced in the absence of oxygen Why is photosynthesis central to energy floes in most ecosystems where does atmospheric oxygen gas come from taking sun s energy plant s photosynthesis Peat bog in Sweden accumulated organic C implications C sequestration and climate change nonrenewable fuel source wetland protection and biome stability Foraminifera type of protest that forms CaCO3 tests shells in oceans 1mm in size Egyptian pyramids made out of foram limestone negative feedback for global warming Nitrogen fixing nodules on soybean roots nodules mostly bacteria and leghemoglobin protein pink inside fixing N2 Nitrogen fixing bacteria 1 micron on root hair 10 microns 25 degrees Celsius 1 atm pressure enzyme nitrogenase contains Fe S Mo forms ammonium then protein by plant Haber Bosch Process Artificial Nitrogen Fixation Fritz Haber 1868 1934 process invented 1908 N2 g 3H2 g 2NH3 g requires 400 degrees Celsius and 200 atm pressure with Fe catalyst in industrial process Major process for fertilizer production a major category of energy consumption in conventional agriculture 50 more N fixed now by humans than by natural processes beginning of artificial fertilizer Nitrogen cycle 9 17 14 OMR Pool storage of carbon Flux amount of carbon transferred from one pool to the other Humans need nitrogen fixation because we need the proteins amino acids made through the plants ecosystem needs nitrogen because plants need nitrogen to grow animals are dependent on the plants carbon and nitrogen cycles are linked photosynthesis capturing carbon from atmosphere making energy for nitrogen fixation Foraminifera form calcium carbonate in the ocean makes shells and limestone become part of the sea floor negative feedback for climate stability increase in CO2 stimulates need