Aquatic Ecosystems

Question 1

How does Depth affect Aquatic Ecosystems?

Answer 1

Determines where plants can grow
Deep Lakes are Oligatrophic, dark & no plants at the bottom, and cooler
Shallow Lakes are Eutrophic, productive to start then become Anoxic (no O2) and warm

Question 2

How does Light affect Aquatic Ecosystems?

Answer 2

Where light reaches is called the Photic Zone (photosynthesis)

Question 3

How does Soil affect Aquatic Ecosystems?

Answer 3

Provides substrate & nutrients for plants in shallow areas

Some organisms live in & under the soil, called Benthos (the soil at the bottom is called the Benthic Zone)

Question 4

How does Turbidity affect Aquatic Ecosystems?

Answer 4

How clear the water is, influenced by: soil, silt, algae/plankton, motion

Turbid= murky (light can’t penetrate)

Question 5

How does Motion affect Aquatic Ecosystems?

Answer 5

Flow rate, waves etc. impact (turbidity, dissolved gases)

Question 6

How does Temperature affect Aquatic Ecosystems?

Answer 6

Temperature influences enzyme activity & therefore living organisms
Temperature influences dissolved gases
More gases is cool
Less if warm
It impacts density (closeness of H2O molecules)
H2O is most dense at 4°C
So ice floats

Question 7

What is a Thermocline in a lake?

Answer 7

Separation based on a steep temperature change

Question 8

What is a Hypolimnion in a lake?

Answer 8

Cool water below the division

Question 9

What is an Epilimnion in a lake?

Answer 9

Warm water above the division

Question 10

What two Elements can impact Aquatic Ecosystems?

Answer 10

Nitrogen & Phosphorus - Botha required for primary productivity

Too much of either (especially PO4 3-) can lead to Algal Bloom. Algal Bloom is an Overgrowth of algae, these algae block out light

Which leads to a decrease in rooted plants, a decrease in O2 levels then death in Organisms. Which leads to an increase in decomposition and CO2 & acidification

Question 11

How does pH affect Aquatic Ecosystems?

Answer 11

Typically neutral is ideal
Too acidic (low pH) = tissues become
damaged

pH is determined by surrounding geology … pollution (burning of fossil fuels)

Question 12

How does Dissolved Oxygen affect Aquatic Ecosystems, and what is Biological Oxygen Demand?

Answer 12

D.O is O2 available to producers & consumer for cell resp. (& nitrification)
    D.O will increase with:
        Decrease in temp
        Increase in motion
        Photosynthesis

High D.O= 😄

B.O.D is the O2 needed for decomposers (bacteria [bacteria remove O2 from the environment before other things can get to it])
= a limit on O2 for all other organisms

High B.O.D= 😡

Question 13

What are three Biological Indicators of Health?

Answer 13

Coliform Bacteria
Aquatic Invertebrates
Amphibians

Question 14

How does Coliform Bacteria work as a Biological Indicator?

Answer 14

It is Intestinal Bacteria, contamination by Fecal matter
    Found in ranching/farming
        Animal feces
    Can cause damage to human water
    treatment facilities

Question 15

How do Aquatic Invertebrates work as Biological Indicators?

Answer 15

Larval/nymph stages of insects 
More diverse populations = healthier
Pollution tolerant species present 
= unhealthy
    Leeches
    Chironomids
Pollution Intolerant species present
= healthy
    Mayflies
    Stoneflies
    Dragonflies

Question 16

How do Amphibians work as Biological Indicators?

Answer 16

Frogs, Salamanders, Caecilians have permeable skin (sensitive to pollutants)
Present = healthy

Many parts to their life cycle 
    Eggs
        They steep in their enviro. which
        can impact development
    Tadpoles
        Are aquatic and they have one diet
        type.  ex. carnivorous
    Adults
        Are terrestrial or amphibious with
        a different diet types ex. 
        herbivorous
    Climate change 
        Leads to a decrease in H2O level
        Increase in UV radiation =
        mutations
    Chytrid Fungus
        Mutagenic Fungus