Lecture 3 & 4 Flashcards
What are some properties of water?
Hydrogen bonds cause water molecules to be cohesive, accounting for high surface tension.
pH of pure water is 7, considered neutral.
ocean’s average pH is slightly alkaline.
What is cohesion?
The attraction between like molecules.
What is adhesion?
The attraction between unlike molecules.
What is capillary action?
The process of a liquid flowing in a narrow space without assistance of external forces.
What is the nature of water?
Thermal capacity/specific heat - water has a high specific heat due to hydrogen bonds, oceans can maintain relatively constant temperature through stability and buffering.
Water and light - much light is reflected into the atmosphere, different wavelengths of life penetrate different depths (attenuation).
What are some factors controlling DO in the oceans?
Biologic Oxygen Demand (BOD), Mixing, Photosynthesis, and Temperature.
What is an oxygen minimum zone? Why?
Areas of the ocean where oxygen levels are low due to biological, chemical, and physical processes. Stratification of the surface water, which limits oxygen from diffusing deeper. Bacterial respiration consumes oxygen. Temperature is warmest towards the surface and oxygen is depleted from this.
What is a thermocline?
A rapid change in temperature in depths of water.
What is a halocline?
A rapid change in salinity in depths of water.
What is a pycnocline?
A rapid change in densities in depths of water.
What is the cause of the ocean’s surface circulation?
The planetary wind + earth’s rotation.
What is fetch?
The distance over which wind blows in a single direction.
What is velocity?
The speed and direction in which a wave moves.
What is a crest?
The tip of a wave.
What is a trough?
The space between the crest and the surface of the wave.
What is the height of a wave?
The area between the crest and the trough.
What is the wavelength?
The distance between two crests.
What is a period of a wave?
The time it takes from wave to meet the position of its prior wave.
What is a spring tide?
When the moon is directly east/west of the earth and linear to the sun.
What is a neap tide?
When the moon is directly north/south of the earth and linear to the sun.
What is a tidal force?
When the moon’s gravitational pull on the earth causes its’ oceans to bulge towards the moon which creates high tides. This also causes the earth to pull towards the moon, creating another high tide on the other side of earth.
What is the tide cycle frequency?
Full cycle: 24 hr 50 mins
Half cycle: 12 hr 25 mins
Half Half cycle: 6 hr 12 min 30 sec
What is a diurnal tide cycle?
One high tide and one low tide per day. (High tide at 1pm, low tide is at 1:25am next day, and next high is 1:50pm next day).
What is a semidiurnal tide cycle?
Two high tides and two low tides same day (same height. High tide at noon, next low tide is at 6:12pm same day, next high tide is 12:25am next day).
What is the Coriolis effect?
Most apparent in the path of an object moving longitudinally, north-south winds will deflect to the right in the northern hemisphere and deflect to the left in the southern hemisphere.
What is the Ekman spiral?
A structure of currents or winds near a horizontal boundary in which the flow of direction rotates as one moves away from the boundary.
What is upwelling?
The rising of seawater (nutrient-rich water reaches the surface of the ocean).
What is downwelling?
The movement of surface water to greater depths.
