IB Environmental systems and societies Topic 4.3E Productivity, Thermal Stratification, Nutrient Mixing, and Loading Revision Notes (HL)

IB Environmental systems and societies Topic 4.3E Productivity, Thermal Stratification, Nutrient Mixing, and Loading Revision Notes (HL) | RevisionDojo

Written by official IB examiners

Productivity Depends on Light, Temperature, and Nutrients

Definition

Primary productivity

Primary productivity is the rate of production of biomass using an external energy source and inorganic sources of carbon and other elements.

Productivity is the rate at which an ecosystem stores energy as organic biomass through photosynthesis.
In aquatic systems, most of it is carried out by phytoplankton.

Note

Three factors set where and when photosynthesis happens: light, temperature, and nutrients.

Light Availability and the Photic Zone

Definition

Photic zone

The photic zone is the upper layer of a body of water that receives enough sunlight to support photosynthesis.

Sunlight powers photosynthesis, but water absorbs and scatters it quickly.
The photic zone, where enough light reaches for photosynthesis, is usually the upper 80 to 150 m.
Below it lies the aphotic zone, too dark for photosynthesis.
Turbidity, depth, and dissolved particles all change how far light travels.

Example

In clear tropical water, light can reach 150 m.
In turbid coastal water, photosynthesis may be limited to about 10 m.

Thermal Stratification: Warm Water Floats and Blocks Mixing

Definition

Thermocline

A thermocline is a layer in a body of water where temperature decreases sharply with depth, restricting vertical movement and mixing.

Water layers by temperature and density.
Warm, less dense water floats above colder, denser water, forming a vertical gradient.
The boundary between them is the thermocline.

Analogy

Think of stratification like a layered cake.
In summer the layers stay separate; in winter they mix into one.

Seasonal Stratification in Temperate Waters

Summer: warm surface water sits over cold deep water, blocking nutrient mixing.
Autumn: cooling surface water sinks and breaks the layering, a process called turnover.

Nice try, unfortunately this paywall isn't as easy to bypass as you think. Want to help devleop the site? Join the team at https://revisiondojo.com/join-us. exercitation voluptate cillum ullamco excepteur sint officia do tempor Lorem irure minim Lorem elit id voluptate reprehenderit voluptate laboris in nostrud qui non Lorem nostrud laborum culpa sit occaecat reprehenderit

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

IB Environmental systems and societies 4.3E Productivity, Thermal Stratification, Nutrient Mixing, and Loading Notes

Productivity Depends on Light, Temperature, and Nutrients

Light Availability and the Photic Zone

Thermal Stratification: Warm Water Floats and Blocks Mixing

Seasonal Stratification in Temperate Waters

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Productivity Depends on Light, Temperature, and Nutrients

Light Availability and the Photic Zone

Thermal Stratification: Warm Water Floats and Blocks Mixing

Seasonal Stratification in Temperate Waters

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

IB Environmental systems and societies 4.3E Productivity, Thermal Stratification, Nutrient Mixing, and Loading Notes

Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

Productivity Depends on Light, Temperature, and Nutrients

Light Availability and the Photic Zone

Thermal Stratification: Warm Water Floats and Blocks Mixing

Seasonal Stratification in Temperate Waters

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Productivity Depends on Light, Temperature, and Nutrients

Light Availability and the Photic Zone

Thermal Stratification: Warm Water Floats and Blocks Mixing

Seasonal Stratification in Temperate Waters

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account