Bio3711 Seawater and Circulation

Physical Properties of Water

An excellent solvent, has a high boiling point and freezing point, and is denser in its liquid form than solid form. Provides a medium for chemical reactions necessary for life.

Water Molecules

Are polar: different parts of the molecule have different charges. The hydrogen bonds create high freezing and boiling temperatures.

Hydrogen Bonds cause water molecules to be ________ ?

Cohesive - stick together. Allows high surface tension.

Adhesion

Attraction to surfaces of objects that carry electrical charges, making them "wet". Also accounts for waters capillary action, the ability of water to rise in narrow spaces.

Which will dry out faster - large sediment particles or small sediment particles?

Coarse large particles dry out faster. Small sediment has more water held by adhesion and capillary action. Due to this held water, meiofauna can live in these environments.

What 6 ions make up 99% of all dissolved salts in the ocean?

Sodium, Magnesium, Calcium, Potassium, Chloride and Sulfate. There are other trace elements that are less than 1 ppm that make up the other 1%.

Dissolved Organic Matter

Goes through a 0.22 micrometer filter. Includes carbohydrates, amino acids, proteins, etc...

Particulate Organic Matter

Retained in a 0.22 micrometer filter. Includes plankton, detritus...

Is the Salinity of surface water varying or constant?

Salinity of surface water varies as a result of evaporation, freezing, precipitation, thawing, and runoff from land. Salinity at the equators is lower than in-between.

Inorganic Carbon and Effects on pH

Bicarbonate and carbonate ions remove H+ from solution. This buffering action helps maintain the pH of seawater at a constant value, providing a stable environment for marine organisms.

Ocean Acidification

Decreasing pH of ocean waters due to absorption of excess atmospheric CO2 from the burning of fossil fuels

Winds

Result from horizontal air movements caused by temperature and density. Hot air is less dense and rises, cool air is more dense and falls.

Coriolis effect

Deflection due to the Earth's rotation

Ocean Surface Currents

Driven mainly by trade winds in each hemisphere, deflected due to Coriolis effect

Gyres

Water flows in a circular pattern around the edge of an ocean basin

Western Boundary Currents

Fastest currents that move warm water towards the poles in each gyre (e.g. Gulf Stream). Not productive, carry little nutrients but increase O2 in water.

Eastern Boundary Currents

Slow moving and carry cold water towards the equator. Productive and nutrient rich.

Thermocline

rapid change in temperature with depth

Halocline

rapid change of salinity with depth

Pycnocline

Rapid change of density with depth. A stable pycnocline can mean reduced vertical mixing and a limitation of nutrients near the surface.

Thermohaline Circulation

An oceanic circulation pattern that drives the mixing of surface water and deep water. Driven by densities of water (caused by temperature). Near the poles, water becomes cooled and salty (and denser) and sinks, carrying O2.

Coastal Upwelling

Wind and Coriolis effect moves water offshore, replaced by deeper , nutrient rich water.