Final exam (Chapter 46-48) Flashcards
1
Q
The Carbon Cycle
A
- 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.
2
Q
Keeling Curve
A
- 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.
3
Q
Photosysnthesis
Photosysnthesis and Respiration in Short-term Carbon Cycle
A
- 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.
4
Q
Aerobic Respiration
Photosysnthesis and Respiration in Short-term Carbon Cycle
A
- 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.
5
Q
Regular Oscillation of CO2 reflects the seasonality of photosynthesis in the Northern Hemisphere
Evidence of the Keeling Curve
A
- 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.
6
Q
Human Activities Play an Important Role In the Modern Carbon Cycle
Evidence of the Keeling Curve
A
- 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.
7
Q
Carbon Isotopes Show That Much of the CO2 Added to Air Over the Past 70 Years Come From Buring Fossil Fuels
A
- 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.
8
Q
The Long-Term Carbon Cycle
A
- Physical processes such as volcanism and climate change.
9
Q
Records of Atmospheric Compositon over 400,000 Years Show Periodic Shifts in CO2 Levels
Vostok and Greenhouse Gas
A
- 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)
10
Q
Reservoirs and fluxes are key in long-term carbon cycling.
A
- 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.
11
Q
Fluxe (3)
A
- 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.
12
Q
Food webs trace carbon and other elements through communities and
ecosystems.
A
- 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.
13
Q
Energy as well as carbon is transferred through ecosystems.
A
- Energy sources for consumers are the carbon-rich organic molecules that the organism eat.
- Unlike carbon, energy cannot be cycled back into the environment
14
Q
Trophic Pyramid
A
- 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
15
Q
Microbial Role
A
While plants and animals are visible, microorganisms, particularly fungi, bacteria, and archaea, play a crucial role in completing the carbon cycle.
16
Q
Limiting Nutrients
A
- 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.
17
Q
The Nitrogen Cycle
A
- 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.
18
Q
Denitrification
A
- A form of anaerobic respiration in which nitrate, rather than oxygen, serves as the terminal electron acceptor.
19
Q
Nitrification
A
- A chemoautotrophic process that uses energy gained from the oxidation of ammonia or nitrite, by oxygen.
20
Q
Anammox
A
- Form of chemoautotrophy, with energy gleaned from the reaction of ammoina and nitrite.
21
Q
Chat Explains: Nitrogen Cycle
A
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.
22
Q
Nitrogen Fixation
A
- 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.
23
Q
Phosphorus Cycles
A
- 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
24
Q
Chat Explains: Phosphorus Cycle
A
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.
25
Ecosystem Framework
## Footnote
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.
26
Photosynthetic Variation
## Footnote
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.
## Footnote
Biological diversity reflects the many ways that organisms participate in
biogeochemical cycles, food webs, and trophic pyramids.
27
Feeding Dynamics
- Heterotrophic bacteria, amoebas, animals, and microorganisms adapt feeding strategies within the food web.
## Footnote
Biological diversity reflects the many ways that organisms participate in
biogeochemical cycles, food webs, and trophic pyramids.
28
Mutual infuence
## Footnote
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.
-
29
Triphic Pyramid Dynamics
## Footnote
Biological diversity can influence primary production and therefore the
biological carbon cycle.
- Primary productivity impacts predator-prey populations in the trophic pyramid
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Reciprocal Enhancement
## Footnote
Biological diversity can influence primary production and therefore the
biological carbon cycle.
High productivity supports biodiversity, and biodiversity, in turn, enhances ecosystem productivity.
31
Diverse Resource and Collective Efficiency
## Footnote
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
32
Evolution of Biological Diversity
## Footnote
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.
33
Climate
- Thought as the long-term average weather
34
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
35
Topography
- Physicla features of earth's surface
36
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.
37
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.
38
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.
39
Ocean currents and heat transport
- Drive the circulation of water at the ocean's surface and transport a large amount of heat from the equator toward the poles.
- Ocean currents, such as the Gulf Stream, transport warm water towards higher latitudes, impacting regional climates.
- Cold, dense water sinks beneath less dense waters, creating a complex 3D circulation in Earth's ocean
40
Global circulation patterns determine patterns of rainfall, but topography
also matters.
- Warm air can carry more water vapor than cold air
- Warm air carries a great deal of water vapour in the equatorial ITCZ
- As air rises and cools, the amount of water vapour decreases, resulting in rain.
- Descending air warms, taking up moisture and generating arid climates
41
Rain shadow
- The moutains themselves impose a regional pattern of rainfall where wet air moves from the ocean up into the moutains, it cools, releases it moisture as precipiation.
- Moving past the moutains, air masses descend and warm up, which takes up water vapour and results in an arid temperature
42
Water Replishment and Concervation in Plants
## Footnote
What cycles and the distribution of terrestrial biomes
- Plant water is mainly replenished through roots absorbing water from soil.
- Plants conserve water in response to limited water resources by clsoing stomata which restricts carbon dioxide intake, thus affecting photosynthesis.
43
Global Water Dynamics
- Most of the water on earth is found below the surface attached to minerals in the mantle.
- Oceans hold about 97& of surface water, while the rest is distributed in other bodies of water.
44
Water Cycles Processes
- Ocean lose water through evaportation and it gets replenished by precipitation
- Winds carry water vapour over land, leading to terrestrial precipitation.
- Water from rainfall may return to the atmosphere through evapotranspiration or be stored as ice, infiltrate sediments, or flow into lakes and rivers.
45
Balancing water fluxes
- Solar radiation and atmospheric circulation influence precipitation and evaporation.
- Changing climate affects regional water controls, impacting ecosystems and human water supply.
46
Terrestial Biomes
- Deserts demand water conservation due to low precipitation; cacti and succulents are common.
- Rainforests, with high precipitation, exhibit high biomass and transpiration rates.
- Temperate zones with intermediate water availability influence global biome distribution.
47
Convergent Evolution and Biome Structure
- Similar plants on different continents result from convergent evolution.
- Vascular plants dominate primary production, shaping biome structures based on water and nutrient availability.
- Primary consumers adapt to plant resources through convergent evolution.
- Detritus (waste) accumulation is decomposed by fungi, protists, bacteria, and soil animals, contributing to a detritus-based food web.
48
Tundra
- Coldest biome
- Short days
- Both temperature and precipitation are low, with the warmest and wettest seasons occuring during the summer.
- The surface of the ground is waterlogged and permanent ice forms in the freezing subsurface.
- Plant diversity is low, and most plants are small.
- Grazers, wolves and foxes are primary consumers.
- Low temperatures and waterlogged soils limit rates of respiration.
49
Alpine
- Similar to tundra, but lacks permanent ice below the soil
- Temperatures vary more widely
- Always lower latitudes belows elevations where snow cover persists throughout the year.
- Thin atmosphere provides limited protection from UV radiation, so many alpine plants are low and slow growing.
50
Temperate Coniferous Forest
- Two broad areas of temperate coniferous forest:
1. Along the Pacific coast where the climate consists of warm summers, mild winters and abundant precipitation.
2. In the interior where there is less precipitation and colder winters.
51
Taiga
- Aka boreal forest, are cool, moist forests.
- The short summer brings rain, and most of the plants are low-growing conifers.
- Soils are deep with accumulated organic matter because the low temperatures result in slow decomp
52
Deciduous Forest
- Seasonal temperatures vartiation and precipitation all year long
- Most subjected to human disturbance for agriculture and urban development.
- Soil is rich in nutrients from annual leaf fall, and the moderate temperatures and precipitation promote decompositon.
53
Temperate Grassland
- Lack of precipitation prevents trees from surviving
- Fires maintain grass population
- Because of decomposers, soil in grasslands accumulate nutrients, providing some of the most productive agricultural lands in the word.
54
Desert
- Continental interiors north and south of the equator
- Wind patterns preent desert biomes from receiving more than a few centimeters of precipitation annually
- Plants have deep roots that have adapted to store water
55
Chaparral
- Reflects a narrow range of climate conditions found on the western edge of continents.
- Prepipiation usually 2-4 months.
- Plants die and reseed themselves every year.
- Drought resistant and ofen adapted to withstand fire.
56
Savanna
- Tall, perennial grasses
- Warm, relatively dry regions with seasonal rain
- Fire play a key role in maintainence
57
Tropical Rainforest
- Most diverse
- Temperatures are warm, and lots of annual precipiation.
- Lots of diversity
58
Aquatic Biomes
- Aquatic biomes: freshwater, estuary, and saltwater.
- One of the most important phenomena when considering the aquatic biome is the depth to which sunlight penetrates through water, which affects the primary producers in aquatic biomes, and it influences food webs in aquatic biomes.
59
Freshwater biomes
- Freshwater biomes include lakes and rivers, varying in climate, nutrient input, and oxygen availability.
- River turbulence ensures well-oxygenated waters, while some lakes can experience stratification with oxygen depletion in deeper parts.
- Seasonal variations in temperature and nutrient influx impact primary producers and photosynthesis rates.
60
Estuaries as Transitional Zones
- Estuaries form at the meeting point of fresh and saltwater, supporting a gradient in species composition.
- Estuaries are highly productive and serve as hatchery areas for commercial fish and shellfish.
- Threats to estuaries include overharvesting, pollution, and human influences.
61
Water distribution
- Less than 3% of Earth's water is freshwater, mainly in glaciers, permafrost, and soil groundwater.
- Oceans cover 71% of Earth's surface, constituting the largest biome.
- Oceans are divided into distinct zones based on depth and proximity to the shoreline: Zones include neritic (coastal), pelagic (open ocean), and deep-sea.
- Photic zone (up to 200 m deep) is vital for photosynthetic organisms, receiving sunlight.
- Pelagic biome faces nutrient scarcity, with a significant part receiving no sunlight.
Deep-sea life relies on organic debris sinking from surface waters and chemoautotrophic bacteria.
- Hydrothermal vents host chemosynthetic bacteria and archaea, supported by high sulfide, hydrogen, and methane concentrations.
62
Intertidal
- Lies along coastline between the mean of high and low tides
63
Coral Reefs
- Coral reefs—another neritic biome—are the most diverse biome in the oceans.
64
Pelagic
- The pelagic zone—the part of the ocean that is neither close to shore nor close to the seafloor—forms the bulk of the oceanic system.
- Sunlight permits photosynthesis
65
Deep sea
- Kilometers below the surface, deep seawaters are cold and dark but not sterile.
66
Liebig's Law of the Minimum
- Idea that primary production is limited by the nutrient that is least available.
- climates near the equator support highly productive forests, whereas dry habitats and cold environments with limited growing seasons have lower levels of primary productivity.
67
Global Distribution of Terrestrial Primary Production (Fig. 47.19)
- Warm and wet climates near the equator support highly productive forests.
- Dry habitats and cold environments with limited growing seasons exhibit lower levels of primary productivity.
- Similarities with global evapotranspiration and precipitation maps highlight the strong influence of climate on terrestrial primary production.
68
Latitudinal Diversity Gradient
- Highest species diversity near the equator, decreasing towards the poles.
- Tropical rainforests showcase extreme biodiversity.
69
Hypotheses for Latitudinal Diversity Gradient
1. Age of Biomes:
- Tropical biomes older, evolving over tens of millions of years.
- Higher latitude biomes changed identity more recently.
- Longer existence in tropics allows more time for evolution and diversification.
2. Adaptation to Climate:
- Temperate communities have fewer species due to difficulty adapting to cold, dry winters.
- Greater environmental variability at higher latitudes leads to broader adaptations, resulting in larger geographic ranges.
3. Species Interactions:
- Insects and fungi attacking specific trees more abundant in wet tropical forests.
- Spacing of trees reduces herbivore encounters, allows more species coexistence.
- Species-area relationship may contribute to diversity gradient.
70
The Anthropocene
- this name emphasizes the dominant impact of humans on the present-day Earth.
- Our collective impact is partly a consequence of our sheer numbers, which in turn drive our energy and land use, but it also re ects the individual and societal choices we make.
71
Energy usage
- energy use by individuals varies greatly from one part of the world to another.
- Americans, Canadians, Europeans, and Australians live energy-intensive lives
- whereas populations in rural Africa and parts of Asia consume relatively little energy per person.
72
Ecological foorpting
- Quantify our individual claims on global resources by adding up all the energy, food, materials, and services we use and estimating how much land is required to provide those resources.
- highly developed countries tend to have large ecological footprints:
EX. 8 hectares of land to support an average American.
- In many parts of Asia and Africa, the average citizen is supported by only a single hectare.
73
Human Influence on the Carbon Cycle
- we contribute to the cycle in which ancient organic matter, or fossil fuel, is oxidized to carbon dioxide, returning to the atmosphere
- The amount of we add to the atmosphere each year by burning fossil fuel is about 100 times that produced by all Earth's volcanoes
EX Clearing forest and agricultural land: No counteracting process removes at comparable rates.
74
Greenhouse effect
- As atmospheric carbon dioxide levels have increased, so has mean surface
temperature.
- Greenhouse gas = co2
Solar Radiation Transmission:
Solar radiation moves downward through the atmosphere.
Some is reflected from Earth's surface, while the rest is absorbed by land and sea.
Energy Absorption and Re-emission:
Greenhouse gases in the atmosphere absorb this infrared radiation and emit it in all directions.
Greenhouse Effect Mechanism:
Greenhouse gases act like the glass panes of a greenhouse.
- especially at high latitudes, the increase has been as much as 2degC
75
Increasing Greenhouse Gas Levels
- Carbon dioxide, water vapor, and methane are crucial greenhouse gases.
- Rising methane levels, partly from increased food production, including cattle and rice cultivation.
- Human activities like natural gas leaks and permafrost thaw contribute to atmospheric methane.
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Biome Distribution and Adaptation According to Climate
- Biomes worldwide closely align with climate patterns, making changes in climate directly impact population distribution and interactions.
- Populations and societies capable of adapting to environmental shifts will persist, while those unable to adapt will face challenges.
77
Weather pattern changes
- Climate-induced temperature increases can lead to longer growing seasons in some regions and exacerbate water availability issues in others.
- Climate models predict significant declines in rainfall, particularly in regions crucial for global corn and wheat production.
- Events like unprecedented droughts in Australia and severe wildfires in North America align with model predictions.
- Hurricans
78
Ecological responses
- understanding of how species will respond to rapid environmental changes.
- Genotypes that were advantageous in the past may not be beneficial in the face of a rapidly changing environment.
79
Plant response to climate change
- With a 2.5°C temperature increase since 1840, many plant species now flower a week earlier.
EX. Responsive species, like Common St. John's wort and highbush blueberry, adjust their flowering time, while less adaptive species decline.
- Across temperate zones in North America, Europe, and Asia, earlier onsets of leaves, flowers, and fruit are observed in response to climate change.
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Plants and climate change (part 2)
- Plants exposed to higher CO2 levels anticipated for the future alter the distribution of products produced through photosynthesis.
- Notable changes include a decline in nitrogen levels within plant tissues and a reduction in the allocation of resources to reproduction.
- The observed alterations in plants are attributed to an individual plant's physiological response to the changing environmental conditions, particularly increased CO2.
- This physiological shift does not imply genetic changes within the plant; it reflects an immediate adaptation at the individual plant level. However, if environmental changes persist over an extended period, the diverse abilities of different plant species to respond physiologically may lead to varying survival and reproductive success.
81
Historical evidence of plant migration
- Fossils from the last ice age reveal that plant species shifted their geographic distributions in response to changing climate.
- Trees, unable to move, migrated through seed dispersal, such as the northward migration of red pines and jack pines.
- Migration as a response to environmental changes requires continuous routes, which can be challenging in landscapes with agriculture and urban development.
- "Assisted migration" involves deliberately transplanting populations to new, more favorable habitats and is suggested to aid in overcoming migration challenges.
- Plants in high latitudes are particularly sensitive to warming, while tropical rainforests may be vulnerable to predicted decreases in cloud cover.
- Changes in water availability can affect plant sensitivity in other regions, potentially leading to diminished population size, decreased growth rates, or extinction.
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Ocean Impact from Climate Change
- The "deadly trio," comprising warming temperatures, ocean acidification, and deoxygenation, poses significant threats to marine ecosystems.
- Increased greenhouse gas levels cause ocean warming, affecting marine animal populations near their thermal tolerance limits.
- Warming impacts primary producers, altering phytoplankton distribution and affecting marine ecosystems, including commercially important fish species.
- Global warming contributes to coral bleaching, harming reef ecosystems, and poses risks to coastal communities through rising sea levels
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Ocean acidification
- Dissolved CO2 forms carbonic acid in seawater, causing a 0.1-unit drop in ocean pH over the past 60 years.
- Ocean acidification reduces carbonate ion levels, making it challenging for marine organisms, especially corals, to build skeletons.
84
Deoxygenation
- Warming seawater decreases its oxygen storage capacity, especially in deeper waters.
- Deoxygenation contributes to expanding low-oxygen zones in oceans, posing challenges for various marine species.
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Importance of Energy Efficiency and Alternative Power Sources
- Success in slowing climate change and ensuring sustainable energy supplies relies on increased energy efficiency and new power sources.
- Renewable sources like solar, wind, geothermal, and nuclear energy are potential alternatives.
- Development of fuel-efficient transportation, airplanes, and buildings is crucial.
- Individual choices, such as using energy-efficient appliances and reducing energy waste, contribute collectively to environmental benefits.
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Actively removing CO2
- Reforestation of previously cleared landscapes removes carbon from the atmosphere becayse plants build miomass from CO2 during photosynthesis
- Capture CO2 as it rises through smokestacks
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Agricultural practices
- Continuous crop harvesting depletes available nitrogen, requiring farmers to add biologically available nitrogen as fertilizer.
- Industrial production of ammonia, derived from nitrogen gas and hydrogen, is a major method for generating fixed nitrogen.
- Nitrate runoff from fields contributes to eutrophication, leading to increased primary production in lakes and oceans.
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Eutrophication and Dead Zones
- Agricultural runoff causes eutrophication, leading to algal and cyanobacterial blooms, which, when decomposed, deplete oxygen in bottom waters.
- The Gulf of Mexico hosts a notorious dead zone caused by nutrient runoff, resulting in mass deaths of fishes and invertebrates.
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Phosphate Fertilization
- Phosphate is a major nutrient used to fertilize fields, and like nitrate, it contributes to environmental issues, particularly eutrophication.
- Overuse of phosphates has detrimental effects on natural ecosystems, causing shifts in plant composition and reducing ecosystem diversity.
EX. Introduced phosphate-loving plants, such as cattails, can outcompete native species in phosphate-enriched environments.
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Humans alter environments
- Human activities alter the selective pressures acting on species, influencing their adaptation and evolution.
- The conscious and inadvertent effects of human actions contribute to changes in biodiversity.
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- Human activities utilize nearly 25% of Earth's photosynthetic output on land.
- This usage includes harvesting crops and livestock, burning biomass, and altering ecosystems through activities like clear-cutting forests.
- Tropical rainforests, holding 50% of Earth's total biodiversity, face severe threats from deforestation.
- Estimates suggest that deforestation in the Amazon forest over the next century could result in the loss of 40% to 50% of all tree species.
- neonicotinoid pesticides in soil and water accurately predict patterns of population decline in bees and birds.
- Millions of tons of plastic enter the oceans annually, impacting marine life, while pollution also poses health risks to humans.
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Overexploitation
- Fishing in newfoundland
- Poaching in african savanna
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- Biodiversity loss has multiple causes, with the introduction of nonnative species being particularly insidious.
EX. Ballast water from ships transporting organisms across oceans and the unintentional transport of insects in imported goods.
- Invasive species can lead to negative consequences for native species and ecosystems, disrupting ecological balance.
- In the modern era, diseases spread rapidly due to global transportation networks.
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Humans have altered the selective landscape for many pathogens.
- The arms race between antibiotics and pathogens is pervasive across various diseases caused by viruses, bacteria, protists, and fungi.
- Tuberculosis is a notable example, with drug-resistant strains evolving due to incomplete antibiotic courses. Antibiotic-resistant tuberculosis cases, including "extremely drug-resistant" strains, pose serious challenges in treatment.
- infectious diseases, like the fungus Batrachochytrium dendrobatidis (Bd), contribute to amphibian decline.
Bd infects frog skin, causing epidemics with rapid geographic spread and high mortality.
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Conservation biology
- addresses the challenge of sustaining biodiversity
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Biology hotspot
- small areas with high numbers of endemic species facing threats from human activities.
- Despite their small size, hotspots support over half of the world's endemic plant species and nearly 43% of its endemic bird, mammal, reptile, and amphibian species, making them high priorities for conservation efforts.
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Genetic variation in concervation
- Genetic variants in plants offer raw materials for breeding crops adaptable to changing habitats
- while marine species show local populations with enhanced evolutionary capacity to tolerate warmer temperatures or decreased pH.
