Oceanography: Density, Seawater, Ocean Salinity, Temperature and Salinity

Ocean Salinity: Consequences of high turbidity

- lower primary productivity - shallow light penetration means plants & algae cannot grow at depths - lower biodiversity - without high primary productivity, fewer species can thrive - lower oxygen levels - primary producers make O2 - higher turbidity - Fewer plants means fewer roots to hold sediments in place in the benthos (bottom) - Will likely affect the pH activity of the region

Density of freshwater

1 g/ml - substance more dense than 1 g/ml will sink in water - substance less dense than l g/ml will float in water

Seawater Chemistry: The degree of angle water is bent at

107.5 degrees

Seawater Chemistry: "Lone Pair electrons"

2 negative electrons that wish to stay as far away from each other as they can

Seawater Chemistry: How many atoms are in one molecule

3 atoms total in one molecule

Ocean Salinity

30-38 ppt

Ocean Salinity: Chesapeake Bay Impact

35.5 million years ago, the Chesapeake Bay was formed by a meteorite impact. This generally marks the deepest part of the Bay, but sediment has filled in much of the impact zone.

Ocean Salinity: Turbidity Current

A turbidity current is a mass of water with a large amount of sediment in suspension. Turbidity currents can cut through sediment on a continental shelf to create submarine canyons and alluvial fans

Atomic Mass

Atomic mass of water: H2O = 2H + 1O = (2*1) + (1*16) = 18 amu Atomic mass of salt: NaCl = 1 Na + 1 Cl = (1*23) + (1*35.5) = 58.5 amu

Seawater Chemistry: What are 6 elements that comprise 99% of seawater

Chlorine, sodium, sulfur, magnesium, and calcium, and potassium.

Ocean circulation: Seawater Density

Density differences between warm/cold AND salt gradients creates a combined stratification (layering) in the ocean waters pyncoline - the layer between bodies of water with different density Seawater Density: measured in g/cm^3 Density is inversely related to the water temperature as water gets warmer the density lowers Density is directly related to the water salinity As water gets saltier the density highers

Ocean Salinity: Water Cycle

Evaporation - water changes from liquid to gas Transpiration - evaporation from plant respiration Condensation - water changes from gas to liquid Precipitation - water falls from the sky as either liquid or solid Infiltration - Water moving into soil and water table Runoff - Water that moves toward the ocean on the land's surface

Seawater Chemistry: Tetahedron

Four sided object.

Seawater Chemistry: Formula for water

H2O

Ocean Stratification observed in three ways:

Halocline: Stratification by salinity gradients Thermocline: Stratification by temperature gradients Pycnocline: Stratification by density gradients caused by combined salinity and thermal differences

Ocean Salinity: Chesapeake Bay rock/sediment

Meteorite estimated at 3-5 km diameter Crater is 40 km across Crater first filled with gravel, cemented together into Breccia rock. Later sands and silts deposited from River runoff.

Ocean Circulation: Other info

Mixed layer: (features) high temperatures, lower salinity, high in motion Pycnocline: (features) low oxygen, high sediment, decomposition, high CO2, highly acidic Deep layer: (features) oxygen, super saturated, high density, low temperatures, show global temperatures only Temperature Conversion Formulas: °F = (1.8 * C degrees) + 32 °C = (F degrees - 32)/1.8

Density of Water

Pure freshwater has a density of 1 g/ml Saltwater usually has a density about 1.03 g/ml Why isn't salt water more dense if NaCl has such a high atomic mass? it is still mostly water

Seawater Chemistry: How difficult is it do get water to freeze

Relatively easy Why? Because of the freezing point being much higher because of hydrogen bonding. From liquid to solid is pretty easy because the liquid water only has 15% more hydrogen molecules than the solid.

Ocean Salinity: Chesapeake Salinity

Salinity of the Chesapeake Bay is due to the dynamic equilibrium created between freshwater runoff from the watershed and salty tidal flow from the Atlantic Ocean. Therefore, salinity of different regions will change daily and seasonally depending on:precipitation, tides, and vertical mixing.

Other stuff:

Stratification - "layering" of water due to different density gradients Where does fresh water go when it enters the oceans? it floats above the saltwater Where does ocean water go when the tides push it into the Chesapeake Bay? It moves into the bay from the bottom and pushes into the bay along the bottom, wedging the freshwater back up-river. Halocline - A boundary between two bodies of water with different salinities Highly acid region of low oxygen where anaerobic bacteria decompose detritus and form acidic Hydrogen Sulfide (H2S)

Ocean Salinity: Turbidity

TURBIDITY is the cloudiness or haziness of a fluid caused by the number and size of particles floating in suspension . CLARITY is a descriptive word that means lack of lack of turbidity . Water Turbidity is measured by how deep one can see into the water. We can measure this with a secchi disk or a turbidity tube.

Ocean Circulation: Temperature and Salinity

Temperature: The mixed layer has higher temperatures due to the direct contact between the water and sunlight, the Pycnocline is a mix of temperatures due to the mixed and the deep layer being above and below it, the deep layer has a colder temperature because there is no contact with sunlight. Salinity: The mixed layer has lower salinity levels, the pycnocline depends on the temperature levels, the deep layer salinity levels affect the temperature.

Seawater Chemistry: What parts of the water molecule are slightly positive?

The Hydrogens are slightly positive, because of the "electronegativity of oxygen." Meaning the measure of how much one atom wants to have electrons and oxygen wants them more than hydrogen. "Electron deficient"

Ocean Circulation: Layering in the terms of density

The Pycnocline is in the middle of the mixed layer and the deep layer, this is where water density increases rapidly with depth because of the changes in temperature or salinity. The deep layer takes up alot of the ocean's mass. Density slowly increases when depth and water move. These layers show how gravity turns liquid into layers. The ocean's pycnocline is the most stable and suppresses mixing between the deep and the mixed layers. This layer acts as a barrier between the two. The mixed layer is a layer that has a mix of different things going on. Currents and the wind both mix this layer of water. This layer responds to the wind, temperature and the rain. This layer creates a uniform density.

Seawater Chemistry: Boiling point of water compare to others

The boiling point of water compares the boiling points of liquid water boils at 100 degrees Celsius. But it is not always like that, water's boiling points can change depending on different altitudes and depending on the pressure around it. So with grain alcohol, the boiling point is 78.3 because the pressure tends to be a lot less for alcohol.

Seawater Chemistry: What part of the water molecule is slightly negative?

The lone pair electrons are slightly negative because of the fact that they are both negative, which drives them to stay away from each other as much as they can.

Seawater Chemistry: Why did the ocean reach an equilibrium of salt

The ocean reached an equilibrium of salt due to multiple reasons. All of the salts have a continental origin. Chemicals were released from weathering then carried to the ocean by stream runoffs. Over time, the concentration of the chemicals increased until an equilibrium was met. Equilibrium occurs when the ocean's water could not dissolve any material into solution. A comparison between old organisms and new organisms was made and they believe that it stopped 600 million years ago.

Where are the salinity lowest:

The salinities are at the lowest when it is towards the bottom and top of the water because the pycnocline of the water by density gradients differs based on the stratification; being at the top and the bottom of the ocean it makes them lower salinity. (glaciers/ice melting)

Where are the salinity highest

The salinities are the highest towards the middle of the ocean because the density of the ocean towards the middle causes the thermocline to be heavier at the middle of the ocean, and being at the middle it causes the salinity to be higher. (hurricanes/heavy rainfall/where hurricanes form)

Seawater Chemistry: Where did the salts in the ocean originally come from:

The salts in the Ocean originally came from the condensation of water found in the earth's early atmosphere as the Earth cooled after its formation. Water was released from the lithosphere as the Earth's crust solidified. Additional water has been added by volcanic eruptions. Scientists recently discovered that maybe comets are a source of water.

Seawater Chemistry: The solid state

The solid state is more dense then the liquid state.

Stratification

The well formed layering of bodies of water based on salinity and temperature

Ocean circulation: Definitions

Thermohaline Circulation: vertical movement of seawater due to changes in density, caused by changes in salinity and temperature. Polar Water convects down to the sea floor, flows outward, across the ocean basin, upwells at continental boundaries. Residence time: (how long does an ion stay in the ocean?) average length of time that an ion remains in solution. Residence time of salts in the ocean is about 3,000 years. Thermo = temperature Haline = salt or salinity Water Stratification: well developed layering of water masses - mostly evident between 40 degrees North and 40 degrees South. Insolation - solar energy striking Earth's surface decreases from equator to poles Isotherms - imaginary contour lines that connect points of equal water temperature (trend east-west on latitudes) Uneven heating of Earth's Surface affects atmospheric circulation and ocean evaporation.

Ocean circulation: Thermocline

Warm layer of water is well mixed due to wind drag and surface currents. depth of the mixed surface layer fluctuates depending on the season.

Seawater Chemistry: Why does water boil at such high temperature

Water also has such a high temperature because of the extensive network of Hydrogen bonds. These bonds are cohesive forces - they want to hold together the molecules. The process of boiling requires that the molecules come apart, and since there are so many of them it causes the process to take longer.

Seawater Chemistry: Define how polarization creates bonding between two different molecules

Water has a slightly negative and slightly positive end which can interact between itself to create an inter molecular network. The positive hydrogen from one end of a water molecule can favor a negative electron off of another water molecule. Every water molecule can form four bonds causing it to make a network of molecules.

Ocean Salinity: Terms and Definitions

Watershed - region of land that has runoff water which will empty into a specific river Estuary - region where saltwater and freshwater mix. Halocline - a horizontal boundary between two bodies of waters with different salinities -high acidity , extremophile bacteria decompose detritus and produce hydrogen sulfide H2S

Other things to know:

What is the typical salinity of ocean water? 35 ppt. What is the density of ice? 917 kilograms per cubic meter water? 1,000 kilograms per cubic meter What temperature does sea water freeze at? 0.0 degrees celsius What gases are found dissolved in seawater? nitrogen, oxygen, carbon dioxide (in the form of bicarbonate HCO3), argon, helium, and neon. How does the amount of carbon dioxide in seawater compare to the other atmospheric gases found there? Compared to the other at

Seawater Chemistry: Explains what happens to water molecules that causes ice to float

When the molecules are tightly formed together this creates a solid, when they melt they move apart and it creates liquid. In water the liquid is more dense than the solid. The Structure of Ice graphic shown, the space between the structure causes it to give ice such low density relative to water.

Ocean Salinity : Factors that contribute to turbidity

inorganic sediments in river discharge - normal weathering & erosion of land organic sediments in river discharge - organic detritus (decomposing remains of plants/animals) nutrient runoff- agricultural fertilizers and animal wastes - both the runoff and resulting algal blooms will contribute to turbidity increased temperatures due to Industrial water use turbidity maximum occurs at the halocline of an estuary - density gradient slows the downward movement of sediment and decomposing bacteria flourish

Density gradient

layers of water with different densities When freshwater runs out into the ocean it floats above the saltwater When ice freezes out of the ocean at the poles the salt left behind increases water density and sinks to the ocean floor

Ocean Salinity: ways to counter act turbidity

regulation of agriculture regulation of other industries crop rotation construction management healthy aquaculture practices More Filter Feeders -- oysters have been the Chesapeake Bay's cleaning system for Thousands of years!