Tema 6 Flashcards
What is the development timeline of estuaries?
Estuaries have existed for about 18,000 years, with some reaching depths of up to 125 meters.
What are fiords in the context of estuaries?
Fiords are coastal estuaries formed by the flooding of glacial valleys.
How are tectonic estuaries formed?
Tectonic estuaries are formed by tectonic activity, such as the sinking of land due to seismic shifts.
What are flooded river valleys or coastal plain estuaries?
These estuaries are formed by the flooding of river valleys and are typically seen in coastal plains.
What is an example of a barrier estuary in Germany and the Netherlands?
Estuaries protected by barrier islands or sandbars.
What is an example of a barrier estuary in North Carolina?
Estuaries protected by the Outer Banks and Hatteras barrier islands.
What are the main factors influencing estuarine circulation?
Estuary shape, wind, evaporation, tidal movements, and river flow.
How do long and narrow estuaries affect tidal currents?
Long and narrow estuaries tend to experience stronger tidal currents.
What is a tidal bore in estuaries?
A tidal bore is an incoming tide that forms a wave moving upstream, such as the one in the Qiantang River.
What is a salt-wedge estuary?
A salt-wedge estuary is where saltwater flows inland beneath freshwater input, creating distinct layers of salinity.
What is a well-mixed estuary?
A well-mixed estuary is one where the water is thoroughly mixed, resulting in uniform salinity.
What is a partially mixed estuary?
A partially mixed estuary has some mixing of saltwater and freshwater but does not completely mix, creating a gradient of salinity.
What types of organisms dominate estuarine ecosystems?
Marine euryhaline species are often dominant in estuarine ecosystems.
What is the significance of salinity fluctuations in estuaries?
Hard substrates experience high fluctuations in salinity, requiring species to adapt.
What are the categories of biodiversity based on salinity levels?
Oligohaline (< 5‰)
True estuarine (5-18‰)
Marine euryhaline (> 18‰)
Marine stenohaline (> 25‰)
Migratory species
How does substrate affect estuarine species?
The physical structure of substrates can vary and influence species’ adaptation to their environment.
How does oxygen availability fluctuate in estuarine environments?
Oxygen availability fluctuates and influences community composition in estuaries.
What is the effect of high sedimentation rates in estuaries?
High sedimentation rates can affect nutrient availability and water clarity.
How does temperature influence estuarine environments?
Temperature affects species distribution and biological processes in estuarine environments.
Why is abundance high in estuaries?
Estuaries have a high carrying capacity due to nutrient availability, but this is dependent on food supply and interspecific competition.
What are the critical factors for food availability in estuaries?
Nutrients and larval supply are critical for food availability in estuarine environments.
How does interspecific competition influence estuarine ecosystems?
Interspecific competition influences community structure and resource distribution in estuarine ecosystems.
What supports primary production in estuaries?
High nutrient availability supports primary production in estuarine ecosystems.
What are photoautotrophs in estuarine systems?
Photoautotrophs include benthic organisms (e.g., diatoms, cyanobacteria, seagrasses) and phytoplankton, which trap nutrients.
