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
Mediterranean Mussel Mytilus galloprovincialis Mid Dark blue; triangular shell; smaller and smoother than California Mussel OCTOPUS: Two-spotted Octopus Octopus bimaculoides Low Two blue, eyelike spots on the web just below the eyes give this octopus its name. CHITONS COMMON NAME SCIENTIFIC NAME ZONE DESCRIPTION Spiny Chiton Nuttallina sp. Mid brown w/ white stripes; girdle has bristles Hartweg’s Chiton Lepidochitona hartwegii Mid (under algae) Olive green with brown stripes; girdle is banded and smooth CRABS COMMON NAME SCIENTIFIC NAME ZONE DESCRIPTION Blueband Hermit Crab Pagurus samuelis Mid (in tidepools) Bright blue bands circle walking legs. Red antennae Hairy Hermit Crab Pagurus hirsutiuculus Mid (in tidepools) White bands on walking legs; brown antennae with bands Striped Crab: Pachygrapsus crassipes High/Mid Reddish purple with green and black stripes across front BARNACLES: COMMON NAME SCIENTIFIC NAME ZONE DESCRIPTION Little Brown Barnacle (small acorn barnacles) Chthamalus dalli Chthamalus fissus High Smooth round margin. Smooth brownish plates Irregular margin. plates. Rough Large Acorn Barnacle Balanus glandula High/Mid Larger in size than Chthamalus Red Thatched Barnacle Tetraclita rubescens Mid/Low Brick red and volcano shaped; ridged or thatched in appearance Gooseneck Barnacle Pollicipes polymerus Mid/Low Stalked with white plates
SEASTARS & SEA URCHINS COMMON NAME SCIENTIFIC NAME ZONE DESCRIPTION Ochre Seastar Pisaster ochraceus Low Can be purple, orange, or brownish red; 5 arms Banded Brittle star Ophionereis annulata Low/ under rocks Gray to light brown with dark rings circling each arm Purple Sea Urchin Strongylocentrotus purpuratus Low Purple with short spines Red Sea Urchin Strongylocentrotus franciscanus Low Red with longer spines Vertebrate List Fish COMMON NAME SCIENTIFIC NAME ZONE DESCRIPTION Tidepool Sculpin Oligocottus masculosus Low Brown to green or reddish on dorsal side Opaleye Girella nigricans Low Brownish green with two white dots on their back ALGAE LIST: GREEN ALGAE COMMON NAME SCIENTIFIC NAME ZONE Sea Lettuce Ulva. sp. Mid Sea Staghorn (Dead Man’s Fingers) Codium fragile Low BROWN ALGAE