APES - Unit 1

carbon cycle

carbon sink

reservoir that takes up more carbon than it releases (ex: ocean)

carbon cycle

carbon source

reservoir that releases more carbon than it takes in (ex: fossil fuel combustion, animal agriculture, deforestation)

carbon cycle

direct exchange

CO₂ moves directly between the atmosphere and ocean

• dissolves into and out of ocean at surface

• happens very quickly & in both directions

• increasing atmospheric CO₂ —> increasing ocean CO₂ —> ocean acidification

carbon cycle

ocean & atmosphere pathways

• algae & phytoplankton: take CO₂ out of the ocean and atmosphere through photosynthesis

• coral, mollusks, some zooplankton: take CO₂ out of the ocean to make calcium carbonate exoskeletons

• sedimentation: calcium carbonate precipitates out as sediment —> settles on ocean floor

carbon cycle

burial

a slow, geological process that stores C in underground sinks (ex: sedimentary rock, fossil fuels)

carbon cycle

fossil fuels

formed from fossilized remains of organic matter into coal or oil —> their decomposition produces natural gas (CH₄)

carbon cycle

extraction & combustion

digging up or mining FFs —> burning them as an energy source —> releases CO₂ into the atmosphere

nitrogen cycle

nitrogen sinks

take N out of the atmosphere in increasing amounts

nitrogen cycle

nitrogen source

release N into the atmosphere

Do N reservoirs or C reservoirs hold N or C for shorter periods of time?

N reservoirs

nitrogen cycle

main N reservoir

atmosphere where N exists as N₂ gas

nitrogen cycle

nitrogen as a nutrient

all living things need N for DNA & amino acids

nitrogen cycle

nitrogen fixation

the process of N₂ gas being converted into biologically available NH₃ (ammonia) or NO₃^- (nitrate)

nitrogen cycle

biotic fixation

certain bacteria that live in the soil or in a symbiotic relationship with plant root nodules convert N₂ into NH₃ (ammonia)

nitrogen cycle

synthetic fixation

humans combust FFs to convert N₂ gas into NO₃^- (nitrate)

nitrogen cycle

assimilation

plants & animals take in N and incorporate it into their biomass

• plant roots take NO₃^- or NH₃ from soil

• animals assimilate N by eating plants or other animals

nitrogen cycle

ammonification

soil bacteria, microbes, & decomposers convert waste & dead biomass back into NH₃ and return it to the soil

nitrogen cycle

nitrification

the conversion of NH₃ into NO₂^- (nitrite) & then NO₃ (nitrate) by soil bacteria

nitrogen cycle

denitrification

the conversion of soil nitrates (NO₃) into nitrogen (N₂) or nitrous oxide (N₂O) gas —> returns to atmosphere

nitrogen cycle

human impacts

• N₂O (nitrous oxide) gas is a greenhouse gas produced by the denitrification of nitrate in agricultural soil —> warms climate

• leaching & eutrophication: synthetic fertilizer use leads to nitrates (NO₃) being carried out of the soil by water —> runoff flows into local waters —> causes algae blooms

individual

one organism

population

group of individuals of the same species

community

all living organisms in an area

ecosystem

all living & nonliving things in an area

biome

the plants and animals found in a region based on yearly temperature and precipitation

symbiosis

a close and long-term interaction between two organisms of different species

mutualism

relationship that benefits both organisms

commensalism

relationship that benefits one organism & doesn’t impact the other

parasitism

relationship that benefits one organism & harms the other

competition

reduces population size since there are fewer resources available & fewer organisms can survive

resource partitioning

different species using the same resource in different ways to reduce competition

temporal partitioning

using resources at different times

spatial partitioning

using different areas of a shared habitat

morphological partitioning

species that hunt for the same resource evolve different body features to eventually utilize different resources (evolution)

phosphorus cycle

the movement of phosphorus atoms and molecules between sources & sinks/reservoirs

phorphorus cycle

reservoirs

rocks & sediments containing P minerals

phosphorus cycle

speed

very slow compared to the other nutrient cycles

• takes a long time for P minerals to be weathered out of rocks & carried into soil/bodies of water

• no gas form of P —> P has to move in slow solid state

• makes it a limiting nutrient for plant growth

phosphorus cycle

phosphorus as a nutrient

all organisms need P for DNA, ATP, bone & tooth enamel

phosphorus cycle

natural sources of phosphorus

weathering of rocks that contain P minerals

• wind & rain break down rock —> phosphate (PO₄^-3) is released and dissolved into water —> rain water carries phosphate into nearby soil/bodies of water

phosphorus cycle

synthetic sources of phosphorus

mining phosphate minerals —> adding them to products like synthetic fertilizers & detergents/cleaners

• synthetic fertilizers are added to lawns or agricultural fields —> runoff carries P into nearby bodies of water

• phosphates from detergents/cleaners enter bodies of water via wastewater from homes

phosphorus cycle

assimilation

• plants: absorb P through roots & assimilate into tissues

• animals: assimilate P by eating plants or other animals

phosphorus cycle

excretion/decomposition

animal waste, plant matter, & other biomass is broken down by bacteria/soil decomposers that return phosphate to soil

phosphorus cycle

assimilation & excretion/decomposition

form a mini-loop within the P cycle

phosphorus cycle

sedimentation

• phosphate doesn’t dissolve well in water —> forms solid bits of phosphate that fall to the bottom as sediment

• P sediments can be compressed into sedimentary rock over long time periods by weight of overlying water

phosphorus cycle

geological uplift

• tectonic plate collision forcing up rock layers that form mountains

• P cycle can start over again with weathering & release of phosphate from rock

eutrophication

• an excess of limiting nutrients N & P in aquatic ecosystems lead to eutrophication —> fuels algae growth

• algae bloom covers surface of water, blocking sunlight & killing submerged plants

• bacteria breaks down the dead matter & use up the oxygen in the water (decomposition is an aerobic process)

• lower levels of dissolved oxygen in the water kills aquatic animals

• bacteria use up more oxygen —> kills more plants and animals until the water becomes a dead zone

hydrologic cycle

movement of H₂O in different states between sources & sinks

What energy drives the hydrologic cycle?

energy from the sun

hydrologic cycle

evaporation

liquid water becomes water vapor in the atmosphere

hydrologic cycle

transpiration

the process plants use to draw groundwater from roots up to their leaves

• leaf openings called stomata open —> allow water to evaporate into the atmosphere

• the movement of water out of the leaf creates low water potential in the leaf —> pulls water up from roots

hydrologic cycle

evapotranspiration

the amount of water that enters the atmosphere from transpiration and evaporation combined

hydrologic cycle

surface runoff

rain flows into a body of water

hydrologic cycle

infiltration

rain trickles through soil into groundwater aquifers (important freshwater reservoir)

• only if the groundwater is permeable

primary productivity

the rate of photosynthesis of all producers in an area over a given period of time

• since photosynthesis leads to plant growth, higher PP = increased plant growth —> more biodiversity

respiration loss (RL)

energy that plants use to do cellular respiration & other processes

gross primary productivity (GPP)

the total amount of sun energy that plants capture & convert to energy through photosynthesis

net primary productivity (NPP)

the amount of energy (biomass) leftover for consumers after plants have used some for respiration

ecological efficiency

the portion of incoming solar energy that is captured by plants & converted into biomass

• approx. 1% of incoming sunlight is captured & converted into GPP via photosynthesis

• the other 99% is reflected or passes through producers w/o being absorbed

• of that 1%, only approx. 40% is converted into biomass/plant growth (NPP)

• some ecosystems are more productive than others

productivity in biomes

• more productivity —> more biodiverse

• water availability, higher temperature, nutrient availability —> lead to high NPP