Wetlands

Question 1

What are coastal Wetlands and which types of coastal wetlands exist?

Answer 1

Coastal Wetlands are wetlands influenced by the flood and decline of oceanic tides.

1. Salt Marshes
2. Mangrove swamp
3. Tidal freshwater marsh or swamp

Question 2

Functions of coastal Wetlands:

Answer 2

Coastal protection
Reduced sedimentation
Reduce pollutants
Provide valuable habitat 
for spawning and feeding

Question 3

Where can you find Tidal Salt Marshes?

Answer 3

Found in intertidal zones, where there is protection from waves, along the coastlines in middle to high latitudes, above 25° N and below 25° S.

Question 4

The type of soil in Tidal Salt Marshes is mainly influenced by:

Answer 4

1. Sediment source: River silt, Coastal sediments and organic production from marsh plants.
2. Tidal current patterns: affect the salinity

Question 5

Which vegetation can you find in Tidal Salt Marshes?

Answer 5

Low marsh: Smooth cordgrass

High marsh: Spike grass, Blackgrass and reed.

Question 6

Which is the most productive wetland ecosystem and why?

Answer 6

Tidal Salt Marshes, because there is a high growth of vegetation and algae (detritus production).
The tides import nutrients, aerate the water, flush toxins, mineral and organic influx and efflux

Question 7

Where can you find Tidal Freshwater Marshes and Swamps?

Answer 7

Inland from coastal salt marshes, intermediate between coastal and freshwater marshes and swamps.

Question 8

Where can you find Mangrove Swamps?

Answer 8

Found in tropical and subtropical regions (between 25°N and 25°S) and also where there is adequate protection from high-energy waves.

Question 9

Which vegetation can you find in Mangrove Swamps?

Answer 9

Red mangrove, black mangrove, white mangrove and buttonwood.

Question 10

Mention the hydrodynamic classification of Mangrove Swamps:

Answer 10

1. Fringe Mangroves
2. Riverine Mangroves
3. Basin Mangroves
4. Dwarf Mangroves
   * go to slides 34 to 37 to check the images with the differences between each classification*

Question 11

Which Mangroves would you expect to be the most and the least productive, and why?

Answer 11

Most productive –> Riverine Mangroves (high amount of nutrients and organic matter, low salinity)
Least productive –> Basin Mangroves (Anoxic conditions, few nutrient flow and high salt concentrations)

Question 12

Mention the functions of the Mangrove Swamps ecosystem:

Answer 12

Export organic matter
provides physical stability for shorelines
Is a sink for nutrients and carbon

Question 13

Mention the characteristics of the Mangrove Swamp soil:

Answer 13

Often acidic.
Variable salinity depending on the season and the mangrove type.
Highly reduced soil (redox potential -100 to -400 mV)

Question 14

What is the difference between Tidal Salt Marshes and Tidal Freshwater Marshes and Swamps?

Answer 14

Tidal Freshwater Marshes and Swamps receive tidal input without the salt stress.

Question 15

What is Redox Potential?

Need to be understood for the exam (professor mentioned in the video)

Answer 15

A measure of the electron pressure or availability in a solution and is used to define the degree of electrochemical reduction of wetland soils. The less electron donors present in a solution, the lower the redox potential.
Example:
Production of methane in a wetland –> extremely reduced soil with very low redox potential

Question 16

Mention the hydrology of Tidal Salt Marshes and its effects on species:

Answer 16

Hydrology dominated by tidal energy.

Tidal Salt Wetlands are dominated by herbaceous vegetation found in the intertidal zone.

Question 17

Wetland Ecosystems can be divided into:

Answer 17

1. Coastal Wetlands

2. Inland Wetlands

Question 18

What is detritus?

Answer 18

A significant source of protein-rich food (microbial biomass) for meio and macro-invertebrates.
Detritus pathway is a very important energy flow in salt marshes.