Ocean systems

What are the four points for thermocline in summer?

- Increase in solar radiation - Solar energy is transferred to top 2-3cm of water in mixed layer increasing the temp - Waves mix the top 25 - 30 cm resulting in fairly isothermal layer' - Deepwater receives no direct energy temp gradually decreases with depth causing TEMP GRADIENT

What are the 6 points that you need to remember for the Deep layer?

- Most dense and stable layer - Higher pressure and salinity - Receives no direct solar radiation, therefore, has the lowest temperature - slow currents - ISOTHERMAL (temperature remains constant throughout) - Makes up 80% of the ocean

What are the two points for thermocline in winter?

- Solar radiation decreases, therefore, mixed layers temperature drops - This results in a more consistent temp gradient between layers and therefore the THERMOCLINE DISAPPEARS

What is the physical pump driven by?

- The solubility of carbon dioxide is a strong inverse function of seawater temperature (i.e. solubility is greater in cooler water) - The thermohaline circulation is driven by the formation of deep water at high latitudes where seawater is usually cooler and denser

Why would increased ocean temps reduce upwelling?

because ocean layers would become more distinct with less mixing between layers and therefore less nutrients brought up to the surface layer therefore less food for plankton to consume

Why is the surface layer rich in oxygen?

because of photosynthesis and contact with atmosphere

Why is the deep ocean water so nutrient dense?

because of the sinking detritus from sea organism and dissovled minerals carried down by density gradients which are the PHYSICAL AND BIOLOGICAL PUMPS

Pressure increases with?

depth

What does the dissolved CO2 from the atmosphere do in our ocean?

diffuses into surface layer some stay as dissolved gases, some get used by phytoplankton or incorporated into shells

What is the physical pump ?

a pump that transports carbon (as dissolved inorganic carbon) from the ocean's surface to its interior.

What do these currents caused by gyres do?

carry heat energy away from tropics to the atmosphere as they travel towards the poles

What direction does the water spin around the hills in the northen hemisphere?

clockwise direction (east/right)

What are the three equations that occur as CO2 undergoes further reactions to result in hydrogen carbonate and carbonate?

1. CO2 + H2O = H2CO3 2. H2CO3 = H+ + HCO3 3. HCO3 = H+ + CO3

What is salinity controlled by? (2)

1. how much water is removed by evaporation (eg warm dry winds) = SALINITY INCREASES 2. how much fresh water is added by rivers precipitation (rain) and ice thawing = SALINITY DECREASES

How does ocean temperature relate to latitude?

Because insolation (INcoming SOLar radiATION) which is the amount of sunlight striking the earth's surface is directly related to latitude eg most sunlight at the equator

The physical pump has a biological coutepart known as the?

Biological pump

Cold water holds more what?

Cold water holds more dissolved gases eg CO2

These two processes act together to do what?

Consequently, these two processes act together to pump carbon from the atmosphere into the ocean's interior.

Salt makes seawater more ...... than freshwater so it .......?

Dense so it sinks

A combination of high salinity and low temp makes seawater?

Dense so much so that it sinks to the bottom of the ocean and flows across ocean basins as deep slow currents.

What is a halo cline?

Halocline, vertical zone in the oceanic water column in which salinity changes rapidly with depth, located below the well-mixed, uniformly saline surface water layer.

What is the exception with high and low salinity of water resting above and below eachother?

Higher salinity water can rest above lower salinity water IF the higher salinity water is sufficiently warm AND the lower salinity water is sufficiently cold

What does upwelling do to growth and reproduction of phytplankton?

It stimulates it

What is El nino (southern oscillation) ?

Large scale ocean atmosphere climate interaction linked to a periodic warming in sea surface temps across central + eastern central equatorial pacific

What are Gyres?

Large scale patterns of currents that circle each of the 5 main oceans

Top Layer?

Mixed layer

What is the biological pump?

The biological pump is the ocean's biologically driven sequestration of carbon from the atmosphere to deep sea water and sediment.[1 It is the part of the oceanic carbon cycle responsible for the cycling of organic matter formed mainly by phytoplankton during photosynthesis (soft-tissue pump), as well as the cycling of calcium carbonate (CaCO3) formed into shells by certain organisms such as plankton and mollusks (carbonate pump).

Near the equator trade winds move in what direction causing the water to do what?

The trade winds move to the east and the water below is pulled in the same direction due to friction

Water ....... at the equator and ..... near the poles?

expands -- contracts

Middle layer?

Thermocline

What is thermocline?

Tropical and subtropical oceans are permanently layered with warm less dense surface water separated from the cold dense deep water by a thermocline a layer in which water temperature AND density change rapidly

T/F cold water is denser than warm water?

True - so it sinks below

What does El nino do to upwelling?

Upwelling at the EASTERN COAST is lessened because pull from wind is decreased + the thermocline has flattened due to smaller temp diff. which results in less nutrients as deep cold water not brought to surface

What does El nino do to the trade winds?

Weakens them as the main heating and evaporation shifts to the east causing a decrease in surface are temp leads to a rise in sea surface temp

What is upwelling?

Wind driven motion of dense cooler nutrient rich water towards the ocean surface replacing the warmer nutrient depeleted surface water

What thermohaline circulation ?

Winds drive ocean currents in the upper 100 meters of the ocean's surface. However, ocean currents also flow thousands of meters below the surface. These deep-ocean currents are driven by differences in the water's density, which is controlled by temperature (thermo) and salinity (haline). This process is known as thermohaline circulation. In the Earth's polar regions ocean water gets very cold, forming sea ice. As a consequence the surrounding seawater gets saltier, because when sea ice forms, the salt is left behind. As the seawater gets saltier, its density increases, and it starts to sink. Surface water is pulled in to replace the sinking water, which in turn eventually becomes cold and salty enough to sink. This initiates the deep-ocean currents driving the global conveyer belt.

What direction does the water spin around the hills in the southern hemisphere?

anticlockwise (west/left)

How do they remove CO2 from the ocean?

combines the CO2 with the H+ ions already present in the ocean with bicarbonate ions reducing the acidity

Before industrialisation what was the CO2 conc in the ocean and what was the equation that represented this?

constant CO2 conc. due to buffering effect which lower acidity the equation = CO2 + CO3 + H2O = HCO3

Why is CO2 important in the ocean?

controls the acidity of seawater

Matter can only be moved by what?

currents

How would decreased upwelling affect the biological pump?

decrease the effectiveness of the biological pump resulting in less carbon being stored in the ocean and deep sea sediments and increase of CO2 in the atmosphere

Why are oceans warmer in the tropics?

due to longer exposure to direct overhead sunlight

Waves transport ...... NOT matter?

energy

Water moves towards the poles due to what?

gravity

What causes gyres?

gravity, coriolis effect solar energy and wind

Higher salinity + colder temperatures + deeper water = ?

higher density

What is the point of thermohaline circulation ?

it carries heat (energy), salt/nutrients (matter) around the planet

how does ocean water move in currents?

it is caused by wind and differences in water density

Warm shallow water with low pressure contains more/less CO2? and what does this mean?

it is under low pressure meaning it contains less dissolved CO2 and is less acidic

Where is oxygen most prominent?

most abundant in the surface layer and in the deep layer bottom but lowest in the pycnocline

What are the major sinks of CO2 in the ocean?

photosynthesis and construction of carbonate shells

How is carbon used by marine organisms?

phytoplankton use is to create organic matter and clams and other things use it to form structual calcium carbonate

Solubility of gases increases with?

pressure

Adding more CO2 to the ocean does what?

produces more H+ ions making the water more acidic (leading to ocean acidification)

Explain the difference between a thermocline and a pycnocline?

pycnocline - a layer where there is a quick change in water density. This is usually due to water temperature in the smaller freshwater bodies such as lakes. However in oceans it is primarily caused by a difference is the salt content in that area. thermocline - is the layer where water temperature decreases rapidly with the depth. Much faster than the usual temperature drop. Below the layer, the water temperatures drop at its usual rate.

How would increased ocean temps (climate change) affect upwelling?

reduces it

What is the coriolis effect?

the deflection to the left (southern hemisphere) or right (northen hemisphere) due to the earths rotation

Temperature and salinity both affect what?

the density of the water, resulting in water moving either up/down through ocean layers causing CURRENTS

Which layer is usually most saturated in gases and why?

the surface layer because of direct exchange with atmosphere

Once the warm water is piled into little 'hills' what does the spin of the earth cause the water to do?

to move around the hill

The trade winds are combined with the expansion of. ....... cause the water to ......?

warm water cause the water to pile into shallow 'hills'

How is pH related to the amount of CO2 dissolved in water?

as it combines with the water to produce carbonic acid which releases H+ ions which are acidic

What are the 5 points that you need to remember for Thermocline layer?

- can be THERMOCLINE (temp gradient remember this by thermo ... like a thermometer) OR PYCNOCLINE (density gradient) - Is the boundary/border between the mixed layer and the deep layer which prevents the transfer of heat/matter - Density increases rapidly with depth due to COLDER TEMPS and HIGHER SALINITY (or higher pressure) - Temperature decreases rapidly with depth - Deeper layer when there are larger differences between mixed layer and deep layer (self-explanatory)

What are the 5 points that you need to remember for mixed layer?

- warmest layer due to absorption of solar energy and heat from the air (atmosphere) - Least dense layer due to LOW SALINITY and WARMER TEMP - Exposed to winds which form SURFACE CURRENTS - Stirring by winds and waves produces a well-mixed layer of similar DENSITY and TEMP (ISOTHERMAL) which 'floats' on the more dense water below - Rich in oxygen because of photosynthesis and contact with atmosphere

Why is the deep layer rich in oxygen?

Because its water is derived from the cold surface waters which sank (CONVECT) to the bottom. Consumption is low because there are fewer organisms and less decay consuming oxygen

What is the chemical equation that link to CO2 dissolving in water?

CO2 + H2O < H2CO3 > HCO-3 + H+ carbon dioxide + water < carbonic acid > bicarbonate + hyrdogen ion

What is pycnocline?

Density varies by latitude and the polar regions do NOT have pycnocline due to the temp being constant Pycnocline, in oceanography, boundary separating two liquid layers of different densities. In oceans a large density difference between surface waters and deep ocean water effectively prevents vertical currents; the one exception is in polar regions where pycnocline is absent. Formation of pycnocline may result from changes in salinity or temperature. Because the pycnocline zone is extremely stable, it acts as a barrier for surface processes. Thus, changes in salinity or temperature are very small below pycnocline but are seasonal in surface waters.

What are trade winds?

Easterly winds are driven by uneven solar heating and the earths spin

What is the biological pump?

Living things move carbon from atmosphere into surface waters then down into deeper ocean and eventually rocks

What is one consequence of this?

One consequence of this is that when deep water upwells in warmer, equatorial latitudes, it strongly outgasses carbon dioxide to the atmosphere because of the reduced solubility of the gas.

What is the differences between a halo cline thermocline and pycnocline?

Pycnocline is the generic term used for rapid vertical changes in the density of a column of water. Thermocline and halocline are then specific reasons for this rapid vertical change. The density gradient is referred to a "thermocline" if the density change is due to temperature (particularly common in fresh water areas). The density gradient is referred to a "halocline" if the density is due to dissolved salt concentrations (particularly common at river estuaries)

What does dissolved CO2 in water do?

acts as a buffer a substance that prevents large shifts in pH levels

When an organism dies it sinks to the bottom what does this decay do?

releases CO2 into the deep water, where it forms layers of carbon rich sediments

The ocean does what with the CO2 in our atmosphere ?

removes 1/2 of it -- it is a 'sink' for carbon

What are the major sources of CO2 in the ocean ?

respiration and decay

Currents get ...... as depth increases?

slower