Ch. 8 Temperate Coastal Seas Between Tropics & Polar Circles (23.5º 66.5º N. & S.) Intertidal Shore Seas to Continental Shelf Ch. 8 Temperate Coastal Lie between Tropics & Polar Circles (23.5º 66.5º N. & S.) Intertidal Shore to Continental Shelf
Coastal Species Many in close association w/ seafloor All large marine plants & algae Benthic species live on or in sediment Impacted by sediments & seawater Seafloor accumulates organic detritus from photic zone Major food source Especially in aphotic zone
Benthic Animals Epifauna: live on sediment Radula tongue Suspension feeders live on rocks or coarse substrate to avoid clogging filters Infauna (macro, micro): live w/in sediment Swallow or displace sediments as they move, burrow amphipod Surf clam Isopod
Benthic Larval Dispersal 75% of slow-moving or attached benthos extend geographic range by broadcast spawning (eggs & sperm) Larvae are temporarily planktonic (meroplankton) Drift w/ currents until meatmorphose into adult forms Sea Urchin Crab Clam Barnacle Seastar
Many larvae don t survive But, survivors extend species geographic range Increase genetic diversity Sea Cucumber
Factors influence larval selection of suitable settling area: Bottom type/ texture, current speed, temp, light, chemicals from conspecific adults Metamorphose into a juvenile form Metamorphose into juvenile form
Intertidal (Littoral) Communities Rocky Shores Sandy Beaches Sandy Beaches
Intertidal Zone Daily tidal fluctuations expose intertidal species to extremes Submergence (High tide): Preferred for most intertidal species (marine) Temp & salinity return to normal, food/nutrients & DO replenished, wastes removed Emergence (Low tide): Dry terrestrial conditions, exposed to air, heat, etc. High Tide Low Tide
Intertidal species must adapt to stresses High tide: Crashing waves, abrasion Low tide: Heat, sun (UV), dryness, No O2 Cold, Freshwater (rainfall & runoff), Predators (birds, terrestrial spp.) Trampling Ochre Seastar
Sandy Beaches Depositional environments Unconsolidated sediment (granite, shell, volcanic), & detritus Waves gentle enough to allow sand accumulation, but wash silt & clay away Longshore currents move sand along shore Animal populations vary seasonally Lower species diversity & density than rocky shores Unsuitable substrate for attachment Little algae & epifauna, mostly infauna
Beach Zonation Most burrow under sediments Increasing Diversity Sand crab (Emerita) East U.S.A.
Filter Feeding Common among beach macrofauna EX: Sand crab (Emerita analoga) Uses feathery antennae to filter plankton, bacteria, & detritus from incoming water Protrudes above sand
CA Grunion (Leuresthes) Reproduction Come out of water to spawn (lay & fertilize eggs) on beach At night from Feb-Sep 1 st 3 hours after highest spring tides (full or new moon) In ~10 days babies hatch & wash out to sea at next high spring tide Female digs tail in sand to lay eggs Male deposits milt (sperm) around her
Sandy Shores California Least Tern, Western Snowy Plover Ground Nesters Endangered species Sand Crab California Least Tern Western Snowy Plover
Rocky Intertidal Rocky Intertidal
Clumped distribution Contradiction: Harsh physical factors: Wave stress, sun, dry Abundant: Food, nutrients, microhabitats & niches Competition for resources: Affects success of species & individuals Rocky Intertidal
Stressful habitat Rocky Shore Wave stress, alternate dry & wet periods, sun (UV) exposure, rocks Vertical Zonation: species adapted to unique conditions Upper intertidal: closest to land, mostly dry. Periwinkle snails, Barnacles Mid-intertidal: ½ Dry, ½ wet Algae, limpets, crabs, mussels, purple sea urchin, Sea anemones Lower intertidal: furthest from shore, mostly submerged. Algae, sea stars, red sea urchin, sea hare, sea cucumber
Increasing Diversity Intertidal Zonation Splash zone: Receive only ocean's salty spray. Flooded only by highest tides & winter storm waves
Upper Intertidal Wet infrequently by high tide, sea spray Lichens & algae store water to avoid desiccation Few invertebrates that tolerate dryness & temp. change Can seal & anchor shells to rock to seal in moisture Barnacles: filter feed during high spring tides Limpets & Periwinkles graze on algae w/ radula Balanus sp. Acmaea sp. Littorina sp.
Middle Intertidal Covered & uncovered 2X/day by tides Species adapted to exposure to air & seawater Dense population = competition for substrate, water, & food Monocultures: Ochre seastar (Keystone sp.) Shorecrab Aggregate anemone asexually divide by fission Ochre sea star Pisaster ochraceous Mussel use byssal threads to cling to rock Hemigraspus sp. Anthopleura elegantissima Mytilus californianus
Middle Intertidal Pelvetia
Lower Intertidal Species cannot tolerate air exposure High diversity Abundant algae, sea grasses Many soft bodied animals Predatory seastars move between mid & low intertidal Nudibranch Sea Hare Bat Star Asterina miniata Sea Cucumber Hermissenda sp. Aplysia californica Parastichopus parvimensis
Oil Spills & the Intertidal Oil released in sea will eventually float to & rest in intertidal Most oil in marine environment enters via urban runoff, dumping Effects of spilled oil depends on type: Light refined petroleum (diesel & gas) mixes in H 2 O column, more toxic, but evaporates quickly & doesn t persist in environment Crude less toxic, but remains on water surface or shoreline much longer, sinks
Oil Tanker Spills Small portion of total marine spills Locally devastating, major cleanup U.S. Oil Pollution Act 1990 (response to Exxon Valdez): all oil-carrying vessels must have double-hull Exxon still appealing $5 billion fine (17 yrs) Selendang Ayu: Aleutian Islands, AK (Dec. 2004) Prestige (2002) Polluted 1000 beaches in Spain & France ~335,732 gallons
Oil Spills & Marine Life Clogs gills of fish & benthic species Damages digestive system Mammals & birds (fur, feathers) lose bouyancy & insulation Exx. Valdez killed 2,000 otters 361 rescued (197 survived) Washing oiled birds
Oil Spill Cleanup Scrubbing w/ high pressure, hot water damage Leave it alone, rely on natural processes Booms, shovels, buckets, absorbent materials Bioremediation by oil digesting bacteria Prestige (Spain) 2002 Exxon Valdez Containment Boom 1989 (Galapagos 2001)
Subtidal (Sub-littoral) Lower intertidal merges w/ upper continental shelf Lower intertidal species also abundant here Beyond effects of tidal action Sediments & detritus accumulate Sandy Areas Turitella sp. Macoma sp. Submerged rocks Ophiura sp. Prestige (Spain) 2002 Brittle star Aphrodite sp. Sea Mouse Polychaete worm
Kelp Forests Dominate subtidal areas w/ rocky outcrops S. California impacts: Overgrazed by urchins (loss of otters) El Nino (high temps.) photosynthesis Suspended organic material from outfalls Decreases photosynthesis Sheephead surfperch
Sewage Treatment & Outfalls Primary Tr. - large solids, grease removed Secondary Tr. Good bacteria eats organic solids, chlorine kills bacteria, chlorine removed (via chemicals) 22% of biosolids sent to farmers chlorine removed (via or compost centers chemicals) 22% of biosolids used by Many chemical farmers or compost centerstoxins, heavy Orange County metals, Many Sanitation chemical toxins, heavy metals, pharmaceuticals pharmaceuticals District outfall: not removed not & enter removed ocean & enter ocean 4 miles off coast of Huntington Beach (200 ft. deep)
Intertidal species must adapt to stresses High tide: Crashing waves, abrasion Low tide: Heat, sun (UV), dryness, No O 2 Cold, Freshwater (rainfall & runoff), Predators (birds, terrestrial spp.) Filter feeders Green Sea Anemone Sandcrab CA mussel Barnacles Ochre Seastar