Final exam (Chapter 46-48) Flashcards
The Carbon Cycle
- A intricately linked network of biological and physical processes that shuttlers carbon among rocks, soil, oceans, air and organisms.
– How carbon moves from one speices to another and between organisms and its surrounding environments.
– Photosynthetic organisms convert the energy of the sun to chemical energy in carbon molecules, and consumers gain energy by eating those molecules. Thus, the carbon cycle also traces the transfer of energy through ecosystem - Helps organize the principle for understanding the ecology and diversity of life on earth.
- The largest amount of carbon is stored in deep ocean water resevoirs.
Keeling Curve
- Chemist Charles David Keeling explored if the concentration of CO2 varies unpredictably from time to time and from place to place.
- EXPERIMENT: 5 towers set 3400 m above sea level, where Keeling sampled the atmophere every hour and measured the composition.
- RESULT: Within the first 5 years, he noticed a pattern of seasonal oscillation where CO2 concentration in the air reached its annual high in the spring and declined to a minimum in early fall.
ANALYSIS: - Initially researchers through that air concentration in Hawaii was influenced by air traffic, but the persistent pattern continued over the years and mirrored monitoring stations worldwide, indicating a global phenomenon.
…Revealed (1) a regular seasonal variation (2) long-term increase in atmospheric CO2 levels.
IN: Annual fluctuation (6ppm) is linked to 47 billion metric tons of CO2 entering and leaving the atmosphere yearly, coursed by respiration, photosysnthesis, geological inputs (volcanoes), mid-ocean ridge, and human actvities, including deforestation and the burning of fossil fuels.
OUT: Geological and biological processes, incuding chemical weathering and photosysnthesi, removes CO2 from the atmosphere.
Photosysnthesis
Photosysnthesis and Respiration in Short-term Carbon Cycle
- Photosnthetic organisms pull CO2 out of the atmosphere and water and the carbon gets transfered to carbohydrates in the Calvin Cycle, and oxygen is given off as a byproduct (2O6 + 6O21H6C − O2H6 + 2OC6).
- Land plants > phytoplankton and seaweed
- If CO2 absense, photosysnthetsis would use up the atmospheric resevoir of CO2 in a few years. However, this is not the case because CO2 is actually increasing according to the Keeling curve.
Aerobic Respiration
Photosysnthesis and Respiration in Short-term Carbon Cycle
- Returns CO2 into the atmosphere.
- Humans and other organisms gain both the energy and carbon needed for growth from organic molecules via food.
- Uses oxygen to oxidize organic molecules to CO2, converting chemical energy in the organic molecules to ATP for use in cellular processes (O2H6 + 2OC6 − 2O6 + 6O21H6C)
- The amount of CO2 returned annully to the atmosphere by aerobic respiration and related processes is about equal to the amount that plants and algae remove by photosynthesis.
Regular Oscillation of CO2 reflects the seasonality of photosynthesis in the Northern Hemisphere
Evidence of the Keeling Curve
- Photosynthesis occurs at higher rates in the summer and at lower rates in the winter (where many plants go dorment and lose their leaves)
- Global atmospheric declines through the northern summer, when rates of photosynthesis are highest relative to respiration, and then increases through fall and winter, when the ratio of photosynthesis to respiration is reversed. The result is the seasonal oscillation of atmospheric levels documented by Keeling.
Human Activities Play an Important Role In the Modern Carbon Cycle
Evidence of the Keeling Curve
- The pronounced upward tick of atmospheric CO2 concentrations since measurements began in 1958 where the overall pattern is an increase.
- Ice sample shows the amount of CO2 in air bubbles trapped in Antarctic ice had started to accumulate since the 1800s, when the industrial revolution happned.
Carbon Isotopes Show That Much of the CO2 Added to Air Over the Past 70 Years Come From Buring Fossil Fuels
- In photosynthesis, enzymes prefer to incorperate CO2 containing the lighter isotope 12C into biomolecules rather than 13C.
- Isotopic Analysis Impact:
Suess’s study reveals a decline in C13, linking it to human activities, especially fossil fuel burning.
The rise in CO2 aligns with a decrease in C14, affirming the influence of fossil fuel combustion.
Confirmed Insights:
Rising CO2 levels are confirmed, with fossil fuel burning identified as a significant contributor.
Ongoing debates center on the climate impact of increasing CO2.
Carbon Cycle Dynamics:
Human activities add about 40 billion metric tons of CO2 annually, with half stored in oceans, vegetation, or soils.
Earth’s carbon cycle involves intricate processes beyond a simple exchange between photosynthesis and respiration. - Thee ratio of di erent isotopes of carbon in the atmosphere indicates that most of the carbon added to the atmosphere in recent decades comes from human activities, particularly the burning of fossil fuels.
The Long-Term Carbon Cycle
- Physical processes such as volcanism and climate change.
Records of Atmospheric Compositon over 400,000 Years Show Periodic Shifts in CO2 Levels
Vostok and Greenhouse Gas
- CO2 levels in the air can change substantial through time.
EX. Vostok: Glacial ice records more than 400,000 years of environmental history, where CO2 oscillated between 285 ppm and 180 ppm. - CO2 is a potent greenhouse gas: it allows incoming solar radiation to reach Earth’s surface but traps heat that is re- emitted from land and sea. Higher concentrations of result in warmer temperatures. Therefore, it is not surprising that climate and atmospheric levels have changed in parallel over the past 400,000 years.
- The curves also relate to the phenomenon of periodic growth and decay of continetal ice sheets. Ice records reflect periodic solar radiation variations due to Earth’s orbit changes.
- We rely on computer models and measurements of chemical or paleontological features of ancient rocks that reflect the levels of atmospheric CO2 at their time of formation (Large degree of uncertainty)
Reservoirs and fluxes are key in long-term carbon cycling.
- Looking at the carbon distribution among its various resevoirs, aka the place where carbon is found on earth.
- Resevoirs include organisms, the atmosphere, soil, the oceans, and sedimentary rocks.
DISTRIBUTION:
- Soil equals combined carbon in land organisms and atmosphere, turing CO2 into a slowly decaying organic compound.
- In the ocean, the amount of carbon contained in lviing organisms is very small.
- The deep oceans have CO2 in the form of bicarbonate and carbonate ions.
- The biggest carbon reservoir are within sediments and sedimatary rocks, especially limestone.
Fluxe (3)
- The rate at which carbon flows from one reservoir to another.
- The same way biological processes elimate and add carbon, physical processes add and remove CO2 from the atmosphere.
1. Volcanoes and mid-ocean ridges release CO2 into the atosphere each year, followed by slow oxidation of coal, oil and other anicent organic material in sedimentary rocks exposed at Earth’s surface (accomplished by bacteria and fugus, but accelerated by burning of fossil fuels)
2. pproximately 0.43 billion metric tons of CO2 is removed from the atmosphere each year by chemical reactions involving air, water and exposed rocks, called chemical weathering that precipiate CaCO3 into the ocean.
3. Techtonic plates is the dynamic movement of the earth’s outer layer. New crust forms on the ocean floor, and sediments accumulate on top of it over time. It forms crusts in the ocean floor where sediments accumulate overtime. Organic carbon within the sediments undergo a process called subduction when one tectonic plate sinks beneath another. During this process, both the crust and the organic carbon are returned to the Earth’s mantle. This recycling mechanism brings the carbon-rich material back into the mantle. Eventually, this recycled material resurfaces through volcanic activity, emitted from volcanoes and mid-ocean ridges where new oceanic crust is formed.
Food webs trace carbon and other elements through communities and
ecosystems.
- Primary producers are autotroph organisms that harness energy from the sun to fix inorganic carbon into organic molecules, sustaining themselves and providing food for others.
EX. Ants eat leaves, ducks eat algae where they obtain the carbon they need for growth and reproduction in the form of energy through respiration. - Organims that are consumers are called heterotrophs.
- Primary consumers consume primary produces (herbivory). They transfer carbon and energy that primary producers drew from an environmental resevoir to a biological reserviur which returns some of the carbon back.
- Secondary consumers are predators that feed on primary consumers, which can also be consumed by tertiary consumers.
- All of the consumers return carbon back to the enviornmental reservoir through cellular respiration
- Decomposers return carbon back to the atmosphere, completing the cycle of the food web.
- An organisms typical food web is called the trophic level.
Energy as well as carbon is transferred through ecosystems.
- Energy sources for consumers are the carbon-rich organic molecules that the organism eat.
- Unlike carbon, energy cannot be cycled back into the environment
Trophic Pyramid
- The biomass supported at each level by the biomass and energy available in the level beneath it.
- Primary production exerts a powerfulence over the rest of the community.
- About 10% of the biomass get tranfered to the trophic levels.
- Trophic levels are inverted with a wide to and low base
Microbial Role
While plants and animals are visible, microorganisms, particularly fungi, bacteria, and archaea, play a crucial role in completing the carbon cycle.
Limiting Nutrients
- Nitrogen and phosphorus determine how much carbon and energy move through ecosystems on land and in seas.
- This is particularly important because they commonly determine the rate primary production within ecosystems occur.
- Because nitrogen and phosphorus come in small amounts, it limits the amount of organic carbon that primary producers introduce into the food web.
The Nitrogen Cycle
- The primary producers, consumers and decomposers are linked to the nitrogen cycle.
- Primary producers from usable nitrogen in the form of nitrate, ammonia, or ammonium in the soil or water in a process called assimilation.
- Primary consumers receive nitrogen just as they recieve carbon (eating)
- The cycle continues, and decomposers return nitrogen as ammonia in ammoification.
Denitrification
- A form of anaerobic respiration in which nitrate, rather than oxygen, serves as the terminal electron acceptor.
Nitrification
- A chemoautotrophic process that uses energy gained from the oxidation of ammonia or nitrite, by oxygen.
Anammox
- Form of chemoautotrophy, with energy gleaned from the reaction of ammoina and nitrite.
Chat Explains: Nitrogen Cycle
Nitrogen Fixation: Nitrogen gas (N2) makes up most of our atmosphere, but plants can’t use it directly. Special bacteria in the soil or in the roots of certain plants (like legumes) convert nitrogen gas into a form that plants can absorb. This process is called nitrogen fixation.
Plant Uptake: Once nitrogen is converted, plants take it up from the soil through their roots. Plants need nitrogen to grow and build important molecules like proteins.
Consumers and Decomposers: Animals eat the plants, and when they die, or when any plant or animal matter decays, bacteria and fungi break down the nitrogen-containing compounds, releasing nitrogen back into the soil.
Ammonification: This is the process where the organic nitrogen from dead plants and animals is turned into ammonium (NH4+), a form of nitrogen that plants can use again.
Nitrification: Ammonium is converted into nitrites (NO2-) and then into nitrates (NO3-) by other bacteria. Plants can absorb nitrates to use them in making proteins and other essential molecules.
Denitrification: Some bacteria in the soil convert nitrates back into nitrogen gas, releasing it back into the atmosphere. This completes the cycle.
Nitrogen Fixation
- The amount of biologically usable nitrogen in communities would decline if it were not for nitrogen fixation, the process by whihc bacteria and archae reduce nitrogen gas to useable ammonia.
Phosphorus Cycles
- Phosphorus is incorporated into the nucleic acids and membranes found in all organisms as well as into ATP.
- Phosphorus is mostly present in rocks, released by chemical weathering.
- Phosphorus does not provide electron donors or acceptors for energy metabolism.
- Once assimilated by primary producers, it is transfered from one organism to another through cycles of consumption and decomposition, returning to geolgic resevoir by accumulation in sedimentaiton.
- In the long term, sediments are uplifted by tectonic plates, making phosphorus availiable again for weathering.
- mining accelerates the phosphorus cycle
Chat Explains: Phosphorus Cycle
Weathering: Over time, rocks break down due to weathering, releasing phosphorus into the soil.
Plant Uptake: Plants take up phosphorus from the soil through their roots. Phosphorus is essential for the formation of DNA, RNA, and other important molecules in plants.
Consumers: Animals get phosphorus by eating plants or other animals. This helps transfer phosphorus through the food chain.
Decomposition: When plants and animals die, bacteria and fungi break down their remains. This decomposition releases phosphorus back into the soil.
Sedimentation: Over long periods, phosphorus can end up in bodies of water through runoff. It settles as sediment at the bottom of water bodies.
Geological Uplift: Over geological time scales, movements in the Earth’s crust can uplift phosphorus-containing rocks, restarting the cycle.
Ecosystem Framework
Biological diversity reflects the many ways that organisms participate in
biogeochemical cycles, food webs, and trophic pyramids.
- Biodiversity is supported by biogeochemical cycles, food webs and trophic pyramids in ecosystems.
Photosynthetic Variation
Biological diversity reflects the many ways that organisms participate in
biogeochemical cycles, food webs, and trophic pyramids.
- Photosynthetic organisms adapt to niches based on environmental factors through structural and phsiological adaptations.
Biological diversity reflects the many ways that organisms participate in
biogeochemical cycles, food webs, and trophic pyramids.
Feeding Dynamics
- Heterotrophic bacteria, amoebas, animals, and microorganisms adapt feeding strategies within the food web.
Biological diversity reflects the many ways that organisms participate in
biogeochemical cycles, food webs, and trophic pyramids.
Mutual infuence
Biological diversity can influence primary production and therefore the
biological carbon cycle.
- The biodiversity reflects its level of primary productivity.
- ## It also reflects the many different ways that plants and animals use the resources provided by soil, water and sunlight in a particular place.
Triphic Pyramid Dynamics
Biological diversity can influence primary production and therefore the
biological carbon cycle.
- Primary productivity impacts predator-prey populations in the trophic pyramid
Reciprocal Enhancement
Biological diversity can influence primary production and therefore the
biological carbon cycle.
High productivity supports biodiversity, and biodiversity, in turn, enhances ecosystem productivity.
Diverse Resource and Collective Efficiency
Biological diversity can influence primary production and therefore the
biological carbon cycle.
- Biodiversity reflects varied resource utilization by different species.
- Diverse species collectively contribute to higher ecosystem productivity
Evolution of Biological Diversity
Biogeochemical cycles weave together biological evolution and
environmental change through Earth’s history.
- Earth’s early carbon cycle involved photosynthetic bacteria and microbial heterotrophs.
- Over time, algae, eukaryotic heterotrophs, sea animals, and seaweeds added complexity to carbon cycling.
- Green algae evolved to live on land, leading to the development of the carbon cycle on land and increased biological diversity.
- Woody plants presented a sharp decline in atmospheric CO2, where the evolution of such trees increased the size of the carbon resevoir on land and ushered in an important new mechanism for removing carbon from the air and transforming it into sedimentary that eveually becomes coal.
- Humans are a huge disruptor of the carbon cycle, particularly fossil fuel buring which leads to climate change.
Climate
- Thought as the long-term average weather
The angle of solar radiation
- In conjunction with the greenhouse effect, solar radiation maintains surface temperatures.
- Earth is hot near the equator because sunlight strikes equatorial regions directly, but at higher latitudes, the curvature of the earth measn that the surface is at an angle to incoming radiation, which is why the poles are cold.
- At the poles experience greater variation of temperatures throughout the year due to the tilt of the earth where solar radiation strikes north american and europe more directly in june than in decemeber
Topography
- Physicla features of earth’s surface
Heat transport by wind and ocean currents
- Warm air rises at the equator, moves towards the poles, cools and then sinks, creating organized atmospheric cells known as hadley cells.
Hadley Cells and Wind Patterns
- Hadley cells explain the circulation pattern of rising and falling air masses near the equator.
- influence wind directions and contribute to heat transport.
Coriolis Effect and Wind Deflection
- Because of Earth’s counterclockwise rotation about its axis, winds in the Northern Hemisphere deflect to the right; those in the Southern Hemisphere deflect to the left.
