 Currents move and mix ocean waters  Transports heat, nutrients, pollutants, and organisms  Affects the marine organisms and Earth’s climate How do you think marine organisms are affected?

 Created by wind pushing the sea surface  Water moves at a 45° angle in opposite direction of wind Due to the Coriolis Effect  tendency of objects moving large distances on Earth’s surface to bend  Bend because Earth is constantly spinning

 Gyres: a large circular system of surface currents that center around latitude 30° in both hemispheres Brings heated water from Equator to polar regions and cold, polar water to Equator Helps regulate Earth’s climate  Why is it necessary to circulate cold and warm water?

 Transport heat throughout the oceans Side that carries water from the Equator will always be warmer Warm waters = coral reefs Cold waters = kelp forests

 Most obvious part of ocean  Carry energy but don’t transport water  Crest: highest part of wave Moves up and forward  Trough: lowest part of wave Moves down and backward  Height: vertical distance between the crest and trough  Wavelength: distance between each wave crest

 Definition: rhythmic pattern of the sea rising and falling  Caused by the gravitational pull of the moon and sun Also caused by the rotation of the earth, moon, and sun  Dominant influence for life near the sea Expose and submerge organisms, drive circulation of bays and estuaries, and triggers spawning

 Since Earth takes 24 hours to complete a rotation  2 high tides and 2 low tides  High tide occurs when location is line with the moon Gravitational pull of moon causes the water to rise  Low tide occurs when location is not in line with moon  Tidal range: difference in water levels between successive high and low tides

 Spring tide: large difference between high and low tide Occur throughout the year Happens at new and full moons  Neap tide: very small difference between high and low tide Occur at first and third quarter moons

 Narrow area of the shoreline that lies between the highest high tide and the lowest low tide  Substrate and effects of tide determine which organisms live where Substrate: type of bottom that a marine organism lives in  Can be rocky or soft-bottom  What do you think would determine if a bottom is rocky or soft-bottomed?

 Found along the coast of California and Cape Cod  Epifauna live on rocky shores Epifauna: organisms that live on the surface of the substrate Can either move over the rocks or be sessile  Sessile: stay attached to rock

 Organisms that live low in intertidal are constantly covered by water  Organisms that live high in intertidal are frequently exposed Need to deal with extreme heat or freezing  can tolerate a wide temperature range  Hide in moist, dark places  Special ridges on shell to help lose excess heat  Dark and light colored shells  How does shell color help the organisms deal with temperature changes?  Dark absorbs heat, light reflects heat

 Upper part of the intertidal only covered by water at high tide Upper part kept wet by wave splash  Desiccation: drying out  Organisms must find ways to prevent it from happening

 Run and hide in a wet place at low tide then return at high tide Hide in tide pools  dents in the rocks that hold seawater once the tide goes out Ex. crabs  Close their shells to seal out moisture Ex. barnacles and mussels  Clamp shell opening to a rock to make a better seal Ex. limpets

 Carve out shallow holes in rocks to make seal more effective Use their shell or radula  Radula: tiny, teeth-like structure  Clump together  Some can tolerate up a 75% loss of water Become crunchy Ex. Seaweed

 Filter feed: filter out nutrients and detritus suspended in water Detritus: dead organic matter and fish poop  Seaweed and detritus are most important food sources  Can scrape algae, bacteria, and other food from rocks  Can be predators

 Organisms that live low in the intertidal have more access to food  Organisms in the high intertidal have limited access to food As a result they:  Move slowly to conserve energy  Grow slower  Can’t filter feed when clamped shut

 Sessile organisms attach themselves to rocks to cope with wave shock Holdfasts: structure used by seaweed to anchor themselves Barnacles secrete a special “glue” to hold themselves onto rocks Byssal threads: strong fibers made of proteins that mussels produce with a special gland in foot  Forms the mussel’s “beard”

 Intertidal fish lack a swim bladder Sink and stay on bottom  Find shelter on shore  Thicker shells  Low profiles to stay close to rocks  Clump together  strength in numbers  Flexible body

 Not a lot of unoccupied space  Limited space = limited intertidal populations  Race to be first to an open spot  give off larvae or spores to settle an clear area  Take over space already occupied  Force another organisms out  Grow over an existing organisms  Grow in colonies  attached to each other Ex. Seaweed

 Soft-bottom: any bottom that is composed of sediment other than rock Gravel Sand Silt Clay  Occur where sediments accumulate

 Infauna: organisms that live in the sediment  Type of sediment determines how much life there is Coarse sand = less water retained  limited animal life Clay and silt = more water  more nutrients and animal life  How tightly packed sediment is determines amount of oxygen available Anoxic: no oxygen  sediment becomes black

 Soft bottoms are unstable and constantly shifting due to waves, tides, and currents  Organisms aren’t sessile  have no place to attach Very few seaweeds

 Change shape of muscular foot Foot thin to reach forward then widens as body passes through Ex. clams  Burrow with spines Ex. sea urchins  Dig with jointed appendages Ex. crabs and shrimp  Eat through sediment Get nutrients from sediment then leave sediment behind Ex. sea cucumbers

 Detritus is the main food source  Diatoms are also a food source Diatom: single-celled algae that look like crystals  2 types of filter feeding: Take in sediment as burrow through sediment  More common in mud bottoms?  Why? Use tube feed to pick up particles  Ex. sand dollars