Microbial Diversity and Ecology: Carbon Cycle and Climate Change

Flashcards reviewing the carbon cycle, microbial roles, and climate change impacts.

What is the role of microbes in the biosphere?

Recycling carbon, nitrogen, and other elements essential for life.

What determines the quality of soil, air, and water?

Microbial activities.

What is profoundly altering geochemical cycles?

Human activity.

How do microbes obtain elements?

Acquiring elements from nonliving components or other organisms.

Where do organisms recycle their components?

The biosphere.

Name abiotic entities involved in recycling.

Water and minerals.

Name biotic entities involved in recycling.

Predators and decomposers.

What is the study of metabolic interactions of microbial communities and their ecosystems?

Biogeochemistry or geomicrobiology.

What do microbial populations generate throughout Earth's biosphere?

Global cycles of elements.

What gas traps solar radiation and releases it as heat?

CO2.

What is the phenomenon of gases trapping solar radiation?

Greenhouse effect.

Which organisms generate greenhouse gases?

Bacteria and methanogenic archaea.

What human activity accelerates the release of greenhouse gases?

Burning fossil fuels.

What accelerates melting and warming as snow and ice melt?

Microbial growth.

What did the rise of ancient cyanobacteria producing oxygen cause?

Mass extinctions.

What can we use to channel microbial activities into recovering the balance?

Microbial ecology.

What is the role of __ in the human-built environment?

Microbial communities.

What does the built environment consist of?

Homes to workplaces and parks.

Name microbial inhabitants that influence our health.

Lactococci to coronavirus.

Give examples of how microbes can help us manage environmental change.

Wastewater treatment and control of greenhouse gases.

What is the highly speculative field that wonders whether biospheres exist on other worlds?

Astrobiology.

What transfers terrestrial carbon into the atmosphere?

Burning fossil fuels.

What has been the result of burning fossil fuels?

Rapid increase in greenhouse gases.

Name the greenhouse gases.

Carbon dioxide, methane, and nitrous oxide.

How do greenhouse gases allow radiation to penetrate the atmosphere but block lower-energy heat radiation from leaving the planet?

Greenhouse effect.

Without a greenhouse effect, what might our planet look like?

Mars.

What might Earth turn into if its temperature increases faster than heat can radiate out?

Venus.

By how much do greenhouse gas emissions need to decrease to avoid a global temperature increase?

Decrease by half.

Name a Swedish activist who demanded that world leaders take action to halt carbon emissions.

Greta Thunberg.

What is the challenge of studying biogeochemical cycles?

Quantification.

Parts of the biosphere that contain major amounts of an element needed for life.

Reservoirs.

What role does each reservoir act as?

Source and sink.

What do the transfer of elements between sources and sinks form?

Global biogeochemical cycles.

What determines the importance of a reservoir for the biosphere?

Rate of cycling.

What forms the largest reservoir of carbon?

Carbonate rock.

What is the source least accessible to the biosphere as a whole?

Earth's crust.

How is subsurface carbon turnover?

Slow.

Which carbon reservoir cycles most rapidly?

Atmosphere.

What is the atmosphere a source of CO2 for?

Photosynthesis and chemolithoautotrophy.

What is the atmosphere also a sink for CO2 produced by?

Heterotrophy and geological outgassing from volcanoes.

What is the major source of carbon for the biosphere?

Ocean.

What is the most important abiotic portion of the carbon cycle?

Dissolving atmospheric CO2 into marine water.

Which organisms release and fix CO2?

Organotrophs and phototrophs/lithotrophs.

Which marine phytoplankton fix as much carbon as all the world's rain forests?

Diatoms.

Name the sources of carbon that are much larger than the atmospheric reservoir.

Oceans, crustal rock, and fossil fuels.

What has perturbed the balance between atmospheric CO2 and larger reservoirs?

Fossil fuels.

What is the annual rate of increase of atmospheric CO2?

2 ppm.

What was the CO2 level measured at Mauna Loa Observatory in 2022?

420 ppm.

What is Earth's dominant source of nitrogen?

Nitrogen gas (N2).

Which organisms perform the biotic processes that fix and return N2?

Bacteria and archaea.

What do the nitrogen cycles of all ecosystems require?

Microbes.

What are the largest reservoirs of nitrogen?

Earth's crust and atmospheric N2.

What does microbial metabolism generate as elements cycle from sources to sinks?

Series of redox changes.

Which organisms were the first to photolyze water and produce molecular oxygen?

Ancient cyanobacteria.

What defenses did microbes evolve to survive?

Antioxidant molecules and enzymes.

How have microbes shaped our biosphere?

Releasing oxygen, fixing nitrogen, and fixing/producing carbon dioxide.

What is the most reduced form of carbon?

CH4.

What is the most oxidized form of carbon?

CO2.

Name the reduced forms of carbon found buried deep underground.

Methane and hydrocarbons (petroleum).

What does the results of carbon cycling differ greatly depending on the presence of?

Molecular oxygen.

Between what does carbon cycle?

Carbon dioxide and various reduced forms of carbon including biomass.

Why is oxidation state important for microbes to use and cycle compounds?

Microbial metabolism.

What methods are used to measure environmental carbon, nitrogen, and other elements?

Chemical and spectroscopic analysis, radioisotope incorporation, stable isotope ratios.

How is atmospheric CO2 measured?

Infrared absorption spectroscopy.

What chromatography is used to separate and quantify gases?

Gas chromatography.

Which method detects extremely small quantities of different molecules?

Mass spectrometry.

What is a small, controlled model ecosystem called?

Mesocosm.

What isotopes do some enzyme reactions show a preference for?

14N versus 15N.

Which organisms strongly prefer the 14N isotope?

Denitrifiers.

How is the 14N/15N ratio measured?

Mass spectrometry.

What kind of remote sensing reveals underground hydrology?

Airborne imaging of magnetic resistivity.

Which terrestrial plants sequester significant amounts of carbon?

Forest trees.

What experiment compares the seasonal patterns of net CO2 uptake for forests at different latitudes?

FLUXNET data.

Who need each other for a continuous cycle?

Both CO2 fixers and heterotrophs.

What determines the rate of carbon cycling and the form of carbon stored in sinks?

Access to oxygen.

What is the largest aerated ecosystem?

Photic zone of oceans.

In the marine photic zone, the ecosystem absorbs enough light for what?

Photosynthesis exceeds heterotrophy.

What does photosynthesis drive?

Biological carbon pump.

What shorthand is used to designate biomass?

[CH2O].

What photoautotrophs that fix carbon included?

Bacteria and protists.

Name marine phototrophs that trap a substantial amount of carbon in biomass.

Diatoms and coccolithophores.

What makes a portion of marine biomass sink to the ocean floor?

Weight of their silicate or carbonate exoskeletons.

What uses O2 to convert [CH2O] back to CO2?

Heterotrophs.

Biomass is also produced through what process?

Lithotrophy or chemolithoautotrophy.

What region supports methanogenic archaea?

Anoxic region.

The methane released forms what?

Methane hydrates.

Warming of methane hydrates may lead to release of gaseous methane which amplifies the greenhouse effect, This is an example of?

Positive feedback loop.

What is essential for the carbon and nitrogen cycles, influencing climate and environmental quality?

Microbial processes.

What do human activities accelerate the release of altering global climate patterns.

Greenhouse gases.

Key components in biogeochemical cycles that act as both sources and sinks for essential elements.

Reservoirs.

The process of methane production, carried out by archaea in anoxic environments.

Methanogenesis.

What is the light-dependent process that fixes carbon dioxide into biomass, performed by phototrophs.

Photosynthesis.

What is the process where organisms derive energy and carbon from organic compounds, releasing CO2.

Heterotrophy.

What is the long-term storage of carbon dioxide or other forms of carbon to mitigate climate change.

Carbon sequestration.

What data is crucial for quantifying the rates of element cycling in ecosystems, especially for gases like CO2.

Flux measurements.

What influences how carbon and other elements are cycled through the environment by microbes.

Oxidation states.

What activities have drastically altered carbon and nitrogen cycles, leading to an increase in greenhouse gases?

Human induced activities on Earth's carbon.

The burning of fossil fuels has led to an increase of what harmful gases?

Carbon dioxide, methane, and nitrous oxide.

Which part of the biosphere acts as a carbon capture to help reduce atmospheric CO2?

The ocean.

In 2022, what was the measured level of CO2 at the Mauna Loa Observatory in Hawaii?

420 ppm.