Currents and Waves Currents: major horizontal movements in a definable path California Current is the principle current in Southern California which is a colder current brought in from the north Other currents during the winter, a counterclockwise current may flow from the – south and during Santa Ana conditions, an offshore current can occur Waves: disturbances that move on or in the water mass which can be created locally or thousands of miles away. Water Temperature January/February at a low of 50-52 degrees August/September at a high of 75 degrees III. Zonation Arrangement of different marine organisms in horizontal bands or zones Zonation will vary from area to area depending upon rock location in respect to the surf Zonation in intertidal waters is determined by physical factors: Substrate Water depth Light There are four recognized zones: Spray (Splash) Zone 5.0 feet and above sea level – High Tide Zone 2.5 to 5.0 feet sea level – Middle Tide Zone 0.0 to 2.5 feet above sea level – Low Tide Zone Below sea level – III. Rocky Shore Characteristics Very Complex Environment very rich biologically – Fixed Substrate Attachment sessile – Adherence motile forms – Desiccation Sessile plants and animals must endure periods of drying out when exposed Motile animals must either move to wetter area are endure periods of drying out when exposed Insolation (radiation from the sun) Direction of rocks (north vs. south facing) Damage to organisms due to: UV light Overheating rocks may get up to 100 degrees Fahrenheit – Wave Action Good wetting, brings up oxygen and food for sessile forms – Bad impact, abrasion from sand and small rocks suspended in water – Salinity Increases in higher tide pools Decreases when: raining (especially at low tide) near the mouths of rivers General Adaptations to a Coast Attachment External protection Escape capabilities Physiological tolerances Factors Controlling marine life Desiccation Light
Currents and Waves Currents: major horizontal movements in a definable path California Current is the principle current in Southern California which is a colder current brought in from the north Other currents – during the winter, a counterclockwise current may flow from the south and during Santa Ana conditions, an offshore current can occur Waves: disturbances that move on or in the water mass which can be created locally or thousands of miles away. Water Temperature January/February at a low of 50-52 degrees August/September at a high of 75 degrees III. Zonation Arrangement of different marine organisms in horizontal bands or zones Zonation will vary from area to area depending upon rock location in respect to the surf Zonation in intertidal waters is determined by physical factors: Substrate Water depth Light There are four recognized zones: Spray (Splash) Zone – 5.0 feet and above sea level High Tide Zone – 2.5 to 5.0 feet sea level Middle Tide Zone – 0.0 to 2.5 feet above sea level Low Tide Zone – Below sea level III. Rocky Shore Characteristics Very Complex Environment – very rich biologically Fixed Substrate Attachment – sessile Adherence – motile forms Desiccation Sessile plants and animals must endure periods of drying out when exposed Motile animals must either move to wetter area are endure periods of drying out when exposed Insolation (radiation from the sun) Direction of rocks (north vs. south facing) Damage to organisms due to: UV light Overheating – rocks may get up to 100 degrees Fahrenheit Wave Action Good – wetting, brings up oxygen and food for sessile forms Bad – impact, abrasion from sand and small rocks suspended in water Salinity Increases in higher tide pools Decreases when: raining (especially at low tide) near the mouths of rivers General Adaptations to a Coast Attachment External protection Escape capabilities Physiological tolerances Factors Controlling marine life Desiccation Light
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