Estuaries-Vegetated Bottoms

Question 1

Types of classification

Answer 1

1. By topography
2. By circulation
3. By stratification
4. By tidal range

Question 2

Types of Topography Classifications

Answer 2

1. Drowned river valley/coastal plain estuary
2. Tectonic estuary
3. Fjords and Rias
4. Sand barrier estuaries and lagoons

Question 3

Drowned River/Coastal Plain Estuary

Answer 3

Topography classification

• Rise in sea level floods the valley of a river, mixing waters
• Shallow
• Average sedimentation
• Most common

Question 4

Tectonic Estuaries

Answer 4

Topography classification

• Flooding resulting from tectonic activity
• Shallow
• In subsidence zones
• Average sedimentation

Question 5

Fjords and Rias

Answer 5

Topography classification

• Results from glacial activity; Ice retreats behind a narrow estuary
• Very Deep and with a sill (No sill = rias)
• Common in high latitudes
• Low sedimentation

Question 6

Sand Barrier Estuaries and Lagoons

Answer 6

Topography classification
- Results from very high sedimentation
- Temporal isolation from the sea
- Most shallow
- Common in low latitudes 
Example: Nambucca River

Question 7

Types of Circulation Classification

Answer 7

1. Positive

2. Negative

Question 8

Positive Estuaries

Answer 8

Circulation classification

• Most common
• Fresh and seawater input

Question 9

Negative Estuaries

Answer 9

Circulation classification

• Uncommon
• Low or no freshwater output
• High evaporation

Question 10

Types of Stratification Classification

Answer 10

1. Highly
2. Partially
3. Not-stratified or vertically mixed

Question 11

Highly Stratified Estuaries

Answer 11

Low degree of mixing

Question 12

Partially stratified estuary

Answer 12

Most common

Question 13

Not stratified estuary

Answer 13

Vertically mixed

Question 14

Types of Tidal Range Classification

Answer 14

1. Microtidal (<2m)
2. Mesotidal (2-4m)
3. Macrotidal ( >4m)

Question 15

Why are estuaries important?

Answer 15

• Highly productive
• Key nursing area for nekton species
• Key feeding grounds for migratory species

Question 16

What ecosystem services do estuaries provide?

Answer 16

• Efficient treatment for coastal runoff

- Filters/traps sediments and pollutants

Question 17

Salt marsh

Answer 17

A grassy area along shores of estuaries

• Floods during high tides
• Associated with tidal creeks and freshwater systems
• Temperature latitudes

Question 18

What latitudes are salt marshes found in?

Answer 18

Temperate

Question 19

Characteristics of salt marshes in spring/early summer

Answer 19

• Growth and expansion

- Colonization of tidal plants

Question 20

Characteristics of salt marshes in the fall

Answer 20

Accumulation of dead leaves during high tide causes an increase in bacterial growth. This causes nitrogen to decrease and the nutritive value decreases.

Question 21

Characteristics of salt marshes in the winter

Answer 21

• Ice cover and recovery

- Initial growth of green plants

Question 22

List the 5 factors that effect salt marsh zonation

Answer 22

1. Tides and flooding
2. Salinity and draining
3. Stability (bioturbation and erosion)
4. Competition for space
5. Grazing

Question 23

How do grazers effect salt marshes?

Answer 23

Periwinkles (grazers) control salt marsh plants. An increase in grazer species causes a decrease in salt marsh plants, but an increase in marsh grabs decreases the amount of periwinkles which increases salt marsh plants.

Question 24

Seagrass

Answer 24

• Found in subtidal, lower intertidal

- Depth point = compensation point

Question 25

Important species of sea grass and where they are located

Answer 25

1. Eelgrass (Temperate and cold areas)

2. Turtle grass (Tropical and subtropical)

Question 26

What organisms are associated with seagrasses?

Answer 26

• Polychaetes
• Sea squirts and bryozoans
• Green algae, herbivore snails
• Grazers like sea turtles and manatees

Question 27

What services do sea grasses provide?

Answer 27

• Big nursery habitats

- CO2 capture

Question 28

What challenges do sea grasses face?

Answer 28

• Affected by fragmentation
• Wasting disease
• Invasive tunicates

Question 29

Mangroves

Answer 29

Plants/trees that have adapted to living in the intertidal

- Tropical (Indo-West Pacific)

Question 30

List the types of mangroves

Answer 30

1. Black
2. Red
3. White

Question 31

White Mangroves

Answer 31

• High tidal level (closer inland)
• No aerial roots
• Diamond shaped seeds

Question 32

Black Mangroves

Answer 32

• Mid/high level waters
• Roots with pneumatophores; root extension over anoxic mud
• Lime shaped seeds

Question 33

Adaptations of black mangroves

Answer 33

1. Pneumatophores: root extension for aeration of plant (over anoxic mud)
2. Salt interchange: selective absorption through roots, salt excretion through leaves

Question 34

Red Mangroves

Answer 34

• Low tide level
• Prominent aerial roots
• Pencil shaped seeds

Question 35

Adaptations of red mangroves

Answer 35

Aerial roots: insert from above water with pores for oxygen absorption

Question 36

What organisms are associated with mangroves?

Answer 36

Sponges, invertebrates and fish

Question 37

What services do mangroves provide?

Answer 37

• Primary producers
• Habitat for many organisms
• Shore stabilizers