Estuaries-Vegetated Bottoms Flashcards
Types of classification
- By topography
- By circulation
- By stratification
- By tidal range
Types of Topography Classifications
- Drowned river valley/coastal plain estuary
- Tectonic estuary
- Fjords and Rias
- Sand barrier estuaries and lagoons
Drowned River/Coastal Plain Estuary
Topography classification
- Rise in sea level floods the valley of a river, mixing waters
- Shallow
- Average sedimentation
- Most common
Tectonic Estuaries
Topography classification
- Flooding resulting from tectonic activity
- Shallow
- In subsidence zones
- Average sedimentation
Fjords and Rias
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
Sand Barrier Estuaries and Lagoons
Topography classification - Results from very high sedimentation - Temporal isolation from the sea - Most shallow - Common in low latitudes Example: Nambucca River
Types of Circulation Classification
- Positive
2. Negative
Positive Estuaries
Circulation classification
- Most common
- Fresh and seawater input
Negative Estuaries
Circulation classification
- Uncommon
- Low or no freshwater output
- High evaporation
Types of Stratification Classification
- Highly
- Partially
- Not-stratified or vertically mixed
Highly Stratified Estuaries
Low degree of mixing
Partially stratified estuary
Most common
Not stratified estuary
Vertically mixed
Types of Tidal Range Classification
- Microtidal (<2m)
- Mesotidal (2-4m)
- Macrotidal ( >4m)
Why are estuaries important?
- Highly productive
- Key nursing area for nekton species
- Key feeding grounds for migratory species
What ecosystem services do estuaries provide?
- Efficient treatment for coastal runoff
- Filters/traps sediments and pollutants
Salt marsh
A grassy area along shores of estuaries
- Floods during high tides
- Associated with tidal creeks and freshwater systems
- Temperature latitudes
What latitudes are salt marshes found in?
Temperate
Characteristics of salt marshes in spring/early summer
- Growth and expansion
- Colonization of tidal plants
Characteristics of salt marshes in the fall
Accumulation of dead leaves during high tide causes an increase in bacterial growth. This causes nitrogen to decrease and the nutritive value decreases.
Characteristics of salt marshes in the winter
- Ice cover and recovery
- Initial growth of green plants
List the 5 factors that effect salt marsh zonation
- Tides and flooding
- Salinity and draining
- Stability (bioturbation and erosion)
- Competition for space
- Grazing
How do grazers effect salt marshes?
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.
Seagrass
- Found in subtidal, lower intertidal
- Depth point = compensation point
Important species of sea grass and where they are located
- Eelgrass (Temperate and cold areas)
2. Turtle grass (Tropical and subtropical)
What organisms are associated with seagrasses?
- Polychaetes
- Sea squirts and bryozoans
- Green algae, herbivore snails
- Grazers like sea turtles and manatees
What services do sea grasses provide?
- Big nursery habitats
- CO2 capture
What challenges do sea grasses face?
- Affected by fragmentation
- Wasting disease
- Invasive tunicates
Mangroves
Plants/trees that have adapted to living in the intertidal
- Tropical (Indo-West Pacific)
List the types of mangroves
- Black
- Red
- White
White Mangroves
- High tidal level (closer inland)
- No aerial roots
- Diamond shaped seeds
Black Mangroves
- Mid/high level waters
- Roots with pneumatophores; root extension over anoxic mud
- Lime shaped seeds
Adaptations of black mangroves
- Pneumatophores: root extension for aeration of plant (over anoxic mud)
- Salt interchange: selective absorption through roots, salt excretion through leaves
Red Mangroves
- Low tide level
- Prominent aerial roots
- Pencil shaped seeds
Adaptations of red mangroves
Aerial roots: insert from above water with pores for oxygen absorption
What organisms are associated with mangroves?
Sponges, invertebrates and fish
What services do mangroves provide?
- Primary producers
- Habitat for many organisms
- Shore stabilizers
