Ecosystem and resource flux

Element cycling

the transport and transformation of chemicals within and among ecosystems - such aas C,N,P,S

Major focal area of ecosystem science:

1. Elements are required by all living organisms

2. Element cycles link the living and non-living parts of the ecosystem 

How do element cycles relate to ecology?

Element cycles interact with physical and biological processes and help us understand ecology and biological diversity.

What components are included in element cycles within an ecosystem?

Element cycles include inputs, outputs, and internal cycling within an ecosystem.

Which law of thermodynamics do element cycles obey?

Element cycles obey the first law of thermodynamics, which states that matter cannot be created or destroyed.

Why are element cycles important in biology?

They are important because they help track the movement of matter and nutrients, which is crucial for sustaining life and ecosystem function.

What happens to elements (nutrients) that cycle in the environment?

They accumulate in reservoirs, or pools.

Give two examples of reservoirs where elements can accumulate.

The atmosphere and sedimentary rock.

What is another term used for places where elements accumulate in the environment?

Pools.

How are element cycles classified?

Element cycles are classified based on the major reservoir where the element resides: gaseous, sedimentary, or hybrid.

What are gaseous cycles and give examples.

Gaseous cycles have main reservoirs in the atmosphere and ocean. Examples include nitrogen (N) and oxygen (O).

What are sedimentary cycles and give an example.

Sedimentary cycles have their main reservoir in the lithosphere (soil, rocks, minerals) and tend to be localized. An example is phosphorus (P).

What are hybrid cycles? Give examples.

Hybrid cycles involve both gaseous and sedimentary reservoirs. Examples include sulfur (S) and carbon (C), with the ocean being a significant carbon sink.

What are the main reservoirs in the lithosphere?

The main reservoirs include the atmosphere, hydrosphere, biosphere, and lithosphere.

What are the three key processes in the “Move, Stick & Change” framework for elemental cycling?

The three processes are: Move, Stick, and Change.

What does “Move” refer to in element cycling?

“Move” refers to the movement of materials within and between ecosystems, also called flux. It is the movement of energy or materials between systems.

What does “Stick” mean in the context of element cycling?

“Stick” means that elements remain for periods of time within pools or reservoirs.

What does “Change” signify in elemental cycling?

“Change” refers to the transformation of elements from one chemical state to another, which influences how they move and stick.

Why is the chemical form of an element important in cycling?

Because the form influences both its movement between systems and how long it stays in a reservoir.

What does the carbon cycle link?

The carbon cycle links biological and physical processes.

Why is the movement of carbon between organisms and their environment important?

It underpins the efficient functioning of ecosystems and their persistence over long periods of time.

What is the main role of the carbon cycle in ecosystems?

It helps sustain ecosystem function by cycling carbon through organisms and the environment.

Who measured changing levels of atmospheric CO₂ using towers in Hawaii?

Charles Keeling.

How did Keeling measure atmospheric CO₂?

He used an infrared gas analyzer to sample the atmosphere at high altitude every hour.

How did CO₂ levels vary seasonally according to Keeling’s measurements?

CO₂ concentrations were highest in the spring and declined by approximately 6 ppm in early fall.

What does this seasonal variation in CO₂ indicate?

It reflects natural processes like photosynthesis and respiration affecting atmospheric carbon levels.

What does the Keeling Curve show about atmospheric CO₂ over the past 60 years?

It shows a steady increase in atmospheric CO₂.

Why does summertime removal of CO₂ not prevent the overall increase in atmospheric CO₂?

Because the CO₂ removed in summer does not fully balance the winter increase, so the annual CO₂ level rises each year.

What is the significance of the Keeling Curve in understanding climate change?

It provides clear evidence of the long-term rise in atmospheric CO₂, which is linked to human activities and global warming.

Where is most carbon stored on land?

Most carbon on land is stored in living organisms and in the soil as decaying organic compounds.

How is carbon stored in the oceans?

Carbon in the oceans is mostly stored as inorganic carbon, with only a small amount in living organisms.

What is the largest carbon reservoir on Earth?

The largest carbon reservoir is in sediments and sedimentary rocks.

How do sediments and sedimentary rocks influence the long-term carbon cycle?

Because they store the most carbon, they act as a slow-release reservoir that regulates atmospheric CO₂ over geological timescales.

What do primary consumers eat?

Primary consumers eat primary producers.

What type of carbon do primary producers fix?

They fix inorganic carbon.

How do primary producers support other organisms?

They provide organic carbon to other organisms.

Give examples of primary producers.

Cyanobacteria, eukaryotic algae, and plants.

Give examples of primary consumers.

Answer: Herbivores and grazers.

What role do primary producers play in a food web?

They form the base of the food web.

Who consumes primary consumers?

Secondary consumers, such as carnivores and scavengers.

What is the role of decomposers or detritivores?

They break down the remains of other organisms into more basic compounds.

Give examples of decomposers or detritivores.

Fungi and earthworms.

In the short-term carbon cycle, how do photosynthesis and respiration relate?

The amount of CO₂ removed by photosynthesis and the amount returned by respiration are about equal.

How do animals contribute to the short-term carbon cycle?

Animals return CO₂ to the atmosphere through respiration.

How do fungi and bacteria contribute to the carbon cycle?

They decompose dead plants and animals, returning CO₂ to the atmosphere.

Why is the short-term carbon cycle important?

It maintains a balance of CO₂ in the atmosphere over short time scales, supporting ecosystem function.

Does energy cycle through an ecosystem like matter?

No, energy does not cycle; new energy must continually be harvested.

Why does a trophic pyramid form?

• Building organic molecules is not 100% energy efficient.

• One trophic level rarely consumes all resources from the level below.

• Energy is lost as heat and through work.

• Biomass decreases from one trophic level to the next.

What happens to energy as it moves up trophic levels?

Energy decreases due to inefficiencies, heat loss, and incomplete consumption.

How does the trophic pyramid reflect energy flow?

It shows decreasing biomass and available energy at higher trophic levels.

What do consumers in the ocean rely on for food?

They rely on organic matter originally generated by primary producers.

What does the diversity of consumers in the ocean reflect?

It reflects evolutionary adaptation to different food sources and predators.

How are ecology and biogeochemical cycling related in the ocean?

They are interconnected; ecological interactions drive the cycling of elements.

What is the role of photosynthetic groups in the ocean?

hey convert CO₂ into organic molecules, forming the base of the marine food web.