Exam Questions Flashcards
What is the definition of an estuary?
- A semi enclosed coastal body of water having free connection to the open sea at least intermittently
- Within which the salinity is measurably different from the salinity in the adjacent open sea.
What is photo-inhibition?
Photo inhibition is light-induced reduction in the photosynthetic capacity of Cyanobacteria,plants and algae.
How does photo inhibition and nutrient limitation further restrict the productive zone in the ocean?
- Phytoplankton do not continue to increase growth with increased radiation-when photo-inhibition occurs.
- It further restricts the productive zone as it causes a finite amount of nutrients to be available. This leads to the growth of the cell slowing down.
What is a thermocline?
- A thermocline occurs when the temperature decreases with depth. The greatest change occurring in the region is called the thermocline.
- In spring and summer months the temperature increases and surface waters are heated, causing a thermocline.
What physical consequences can stratification have on the water column?
The water column becomes stratified (layered) which :
- Suppresses mixing
- Depletes nutrients on the surface layers
- Alters gaseous equilibria
- Creates barriers to movement (density)
Describe how the consequences of stratification have marked ecological implications?
- For species that migrate vertically, going down the water column and back up, it creates barrier for them as movement barriers have occurred.
- As it depletes nutrients on the upper water layers, this can have ecological implications on phytoplankton as they will not have all necessary nutrients required for growth.
Identify the major processes that form the oceans.
- Seafloor spreading
- Young ocean basins
- Matching coastlines frame
- Plate tectonics
- Plate divergence
Identify the main theories behind continent formations
- Pangea: Continents collided to form a large landmass.
- A Worldwide ice age
- Tropical areas once located closer to poles
Describe Seafloor spreading.
-Seafloor spreading was given proof due to the magnetic anomalies.
It occurs when the floor of the sea spreads.
Describe the formation of young ocean basins.
Upwelling occurs above the outer core causing a mid-oceanic ridge pushing ocean water to both the left and the right. The oceanic lithosphere is visible near the mantle.
Visible trenches are seen either side of the mid-oceanic ridge.
Describe the effect of salinity in oceanic waters
The total amount of solid material dissolved in water including dissolved gases but excluding dissolved organic substances.
Heating and salinity (Thermohaline) determine the density of water.
What is Thermohaline?
The temperature (thermo) and salinity (haline) determine the density of the water.
Density is measured by mass/volume.
What influence do salinity and temperature of seawater have on ocean circulation?
- They cause Thermohaline circulation.
- Main driver of large scale vertical circulation.
- Changes in temperature and salinity cause surface changes and therefore have circulation results.
Are temperature and salinity affected by organisms?
No they are not affected by organisms and they are retained as the water sinks.
Describe surface circulation.
Surface circulation:
- considered to be wind-driven
- warm surface waters tend to float
- vertical transport is slow
