WorksheetsOCE: Ocean Chemistry Lab– Investigating Density & Stratification
Total questions: 60
Worksheet time: 34mins
What primarily determines the density of surface seawater?
Pressure
Temperature and salinity
Wind speed
Ocean depth
What happens to seawater density when salinity increases?
Density decreases
Density remains constant
Density increases
Temperature increases
Which factor has the least effect on surface seawater density?
Temperature
Salinity
Pressure
Latitude
What is the typical density range of seawater?
1000–1010 kg/m³
1020–1030 kg/m³
1040–1050 kg/m³
990–1000 kg/m³
What causes the volume of seawater to increase?
Increased salinity
Increased temperature
Increased pressure
Decreased temperature
What is the name of the ocean layer where temperature decreases rapidly with depth?
Mixed layer
Thermocline
Halocline
Pycnocline
What is the term for the upper layer of the ocean that is directly heated by solar radiation?
Mixed layer
Thermocline
Pycnocline
Deep layer
What causes seasonal changes in the depth of the mixed layer?
Salinity changes
Surface winds and storms
Ocean currents
Pressure differences
What is the temperature at the bottom of the thermocline in a temperate ocean profile?
10°C
0°C
4°C
18.5°C
What term describes the vertical layering of water based on density?
Circulation
Stratification
Upwelling
Stability
What is the term for a water column with uniform density throughout?
Thermocline
Halocline
Isopycnal
Pycnocline
What is the term for the zone where light penetrates the ocean and supports photosynthesis?
Mixed layer
Euphotic zone
Thermocline
Pycnocline
What is the term for the production of organic compounds from carbon dioxide through photosynthesis?
Stratification
Primary production
Upwelling
Overturning
What is the term for the vertical column of water from surface to depth?
Thermocline
Water column
Pycnocline
Halocline
What is the term for the process that moves heat, gases, nutrients, and pollutants globally?
Upwelling
Thermohaline circulation
What is the term for the layer where salinity changes rapidly with depth?
Thermocline
Halocline
Pycnocline
Mixed layer
What is the term for the layer where density changes rapidly with depth?
Thermocline
Halocline
Pycnocline
Mixed layer
What is the term for the process where deep, cold, nutrient-rich water rises to the surface?
Stratification
Upwelling
Overturning
Primary production
What happens to the mixed layer during winter at mid-latitudes?
It becomes shallower
It becomes deeper
It disappears
It warms significantly
What is the term for the process of vertical mixing that disrupts stratification?
Stratification
Upwelling
Overturning
Primary production
What causes seawater density to increase?
Decrease in salinity
Increase in temperature
Increase in salinity
Decrease in pressure
What is water stratification?
Mixing of water layers
Layering of water masses based on density
Heating of surface waters
Movement of water due to wind
In a stable water column, how does density change with depth?
Density decreases
Density increases
Density remains constant
Density fluctuates randomly
What is a “cline” in oceanography?
A. A type of ocean current
B. A layer where properties change rapidly with depth
What is the pycnocline?
A layer of constant temperature
A layer where density changes rapidly with depth
A zone of high salinity
A surface mixing zone
What is an isopycnal?
A layer of constant temperature
A layer of constant density
A zone of rapid salinity change
A surface mixing zone
What causes overturning in polar regions?
Increased solar radiation
Extremely cold temperatures and sea ice formation
Decreased salinity
Increased wind speed
How can overturning affect biological productivity?
It reduces nutrient availability
It influences timing and location of productivity
It stabilizes the water column
It prevents mixing of water layers
Fill in the blank: ________ is the global ocean circulation driven by differences in temperature and salinity.
Thermohaline circulation
El Niño
Gulf Stream
Monsoon current
Fill in the blank: ________ is the mass per unit volume; determines water layering and movement.
Density
Temperature
Salinity
Pressure
Fill in the blank: ________ is the layering of water due to differences in density.
Stratification
Evaporation
Condensation
Precipitation
Fill in the blank: ________ is the resistance of water layers to mixing; stable layers resist vertical movement.
Stability
Salinity
Turbidity
Conductivity
Fill in the blank: ________ is a surface or layer of constant density.
Isopycnal
Isotherm
Isohaline
Isobar
Fill in the blank: ________ is a layer in the ocean where density changes rapidly with depth.
Pycnocline
Thermocline
Halocline
Abyssal plain
Fill in the blank: ________ is a layer where temperature changes rapidly with depth.
Thermocline
Lithosphere
Halocline
Mesosphere
Fill in the blank: ________ is a layer where salinity changes rapidly with depth.
Halocline
Thermocline
Pycnocline
Oxycline
Fill in the blank: ________ is a vertical section of ocean water from surface to bottom.
Water column
Thermocline
Continental shelf
Abyssal plain
Fill in the blank: ________ is a body of water with distinct temperature and salinity characteristics.
Water mass
Estuary
Lagoon
Stream
Fill in the blank: ________ is the upper layer of the ocean where sunlight penetrates.
Photic zone
Abyssal zone
Benthic zone
Bathyal zone
Fill in the blank: ________ is the portion of the photic zone where photosynthesis can occur.
Euphotic zone
Aphotic zone
Benthic zone
Abyssal zone
Fill in the blank: ________ is the creation of organic compounds by autotrophs (e.g., phytoplankton) using sunlight and CO₂.
Primary production
Decomposition
Respiration
Fermentation
Fill in the blank: ________ is the surface layer of the ocean mixed by wind and waves.
Mixed layer
Abyssal plain
Thermocline
Continental slope
Fill in the blank: ________ is the vertical mixing of water layers, often seasonal.
Overturning
Stratification
Evaporation
Sedimentation
Fill in the blank: The rising of deep, nutrient-rich water to the surface is called _________.
Upwelling
Downwelling
Evaporation
Condensation
Fill in the blank: A condition where denser water lies above less dense water, promoting mixing, is known as an _________
Unstable water column
Stable water column
Thermocline
Halocline
Fill in the blank: Mid-latitude regions with seasonal temperature variation are referred to as _________.
Temperate latitude
Tropical zones
Polar regions
Desert zones
Fill in the blank: High-latitude regions with cold, relatively uniform temperatures are called _________.
Polar latitude
Tropical zones
Temperate regions
Desert areas
Fill in the blank: A gradient or transition zone in the ocean (e.g., thermocline, halocline) is called a _________.
Cline
Gyre
Atoll
Trench
This describes the condition where denser water is sitting above less dense water, which goes against the natural layering of the ocean. It’s a setup that leads to mixing. (a) The process that happens because the water column is unstable is (b) .
is common in polar regions where surface water becomes very cold and salty, especially due to sea ice formation. This increases density and causes the water to sink.
Upwellling
Overturning
Thermal Expansion
Where is upwelling most likely to occur?
In the middle of ocean gyres
Along coastlines with strong winds and cold currents
In deep ocean trenches
Near the equator where water is warmest
(a) brings nutrient-rich water to the surface, fueling phytoplankton growth and supporting the entire food web, including fisheries.
Why is upwelling important for marine ecosystems?
It warms surface waters, helping coral reefs grow
It brings oxygen to the deep ocean
It delivers nutrients to the surface, boosting primary productivity
It reduces salinity in surface waters
(a) is driven by wind blowing along the shore. The Coriolis effect causes surface water to move away from the coast, and deeper water rises to replace it.
What is upwelling?
The sinking of cold, dense water in polar regions
The mixing of surface water due to tides
The rising of deep, nutrient-rich water to the surface
The movement of warm water toward the poles
What causes overturning in the ocean?
Differences in temperature and salinity
Changes in pressure at the ocean floor
Tidal forces
Wind and surface currents
(a) is the upward force that water exerts on objects or water parcels. In oceanography, it explains why some water masses float, sink, or stay suspended based on their density.
This is the area of sudden change in temperature in water.
Halocline
Thermocline
Pycnocline
Surface Tension
What is the primary source of heat for the ocean’s surface?
Solar radiation from the sun
Reflected heat from the atmosphere
Heat from ocean currents
Heat from underwater volcanoes
In which region would you expect the thermocline to be strongest?
Polar regions
Deep ocean trenches
Coastal upwelling zones
Equatorial regions
