Basics Intertidal zone Between tides Littoral zone Best studied areas Emersion vs. Immersion Few marine places open to air Must give up advantages Habitat The tides/community rely on type of bottom

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Basics cont. Habitat Community-all the different pop. in an area Bottom-the material which organisms live on Substrate/substratum Different bottoms define habitat

Low Tide Exposure Problems Harsher environment Higher up more time out of water The highest is never submerged Water Loss Desiccation Must tolerate, or prevent it Two main ways, hiding or “clamming up”

Low Tide Exposure Water Loss Hiding Go run and hide to somewhere wet Tide pools Sessile organisms only spawn in wet areas “Clam up” Some protective covering Holds water, and they go in to their covering Some clamp themselves to rocks

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Rocky Bottom Communities Basics Formed by Active coasts uplifting Ice scraping and weighing Waves carry away/erode Organisms Most are epifaunal Many are sessile Both cause stress

Low Tide Exposure Water Loss “Clam up” Some close off their operculum Not caring Chitons and rockweeds just don’t care Temperature and Salinity Heat capacity allows for moderate water temp

Low Tide Exposure Temperature and Salinity Air temp. is more extreme Most are eurythermal Some hide in the shade Some colors are lighter Salinity also affects organisms Some clam up Some burrow (more common in soft)

Low Tide Exposure Restriction of feeding Deposit uncommon (rocky) Filter common among sessile Only underwater Others eat detritus or seaweed Predatory problems at low tide Not being able to eat at higher up in the habitat Slower development

The Power of the Sea Waves The distribution of wave action is varied Refraction not perfect Bays less action, headlands more Wave impact intensity (wave shock) is varied Coping with Wave Shock Some only live sheltered Deal with sediment more

The Power of the Sea Coping with Wave Shock Some anchor themselves to rocks Seaweed-holdfasts Mussels-byssal threads Move slowly Suction cups No swim bladder Anchoring can disadvantageous Thicker shells This causes greater diversity among locations

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The Battle for Space Space limitation Plenty of food Limiting resource is mainly open space Ways to compete First one there Quick dispersal Forcing out others Growing over others

Vertical Zonation of Rocky Shores Basics Community divided into bands One organism won’t exist throughout Vertical zonation General rule Upper limit physical Lower limit biological Not perfect Fuzzy Split into Upper, middle, lower Not universal

Vertical Zonation of Rocky Shores Upper intertidal Highly exposed to air Above high tide line Affected by splash “splash zone” Farther on exposed coasts Organisms Lichens Cyanobacteria Algae Periwinkles Littorina zone Limpets

Vertical Zonation of Rocky Shores Middle intertidal Parts are submerged more than others Causes greater diversity Top almost always has barnacles Due to larva, predation, and desiccation tolerance Bottom limit from predation/competition Have to stop from drying out Other parts are determined by the specific site

Vertical Zonation of Rocky Shores Middle intertidal The middle of the middle is dominated by Mussels, barnacles, and brown seaweeds Seaweed forms algal turf Mussels killed by sea stars, or spiny lobsters Keystone predator Ecological succession Final climax community Not always typical Diversity increases with competitive exclusion

Vertical Zonation of Rocky Shores Lower intertidal Immersed mostly Many predators Many seaweeds Light and space limited Self sustaining tide pools

e.com/watch?v=g7 Rlh5sA8WE

Soft Bottom Intertidal Communities Basics Any bottom composed of sediment Can be confusing For book is burrowable Dominate east Cape Cod and the Gulf The shifting sediments Unstable ground Less seaweed, more seagrass

Soft Bottom Intertidal Communities The shifting sediments Most organisms are infaunal Protection from physical and predators Most sediment is a mix Calmer=finer Rougher=larger Living in the sediment Oxygen availability Detritus main source of food Deposit feeders

Soft Bottom Intertidal Communities Living in the sediment Oxygen availability Oxygen and detritus is dependent on sediment size Coarser=more This is due to the porosity of the sediment In muddy bottoms, the organic matter uses the little bit of oxygen Interstitial water Anoxic bacteria thrive Others bioturbate Others have special hemoglobin And others are lazy

Soft Bottom Intertidal Communities Living in the sediment Getting around To move around Clams use muscular foot Worms open a path with their pharynx Crustacean dig Some eat while moving through the sediment Meiofauna live in between the grains and are worm- shaped

e.com/watch?v=vN qEQjGaDVk

Soft Bottom Intertidal Communities Living in the sediment Feeding Plankton and diatoms are major primary producers Suspension feeders lay out a net to catch detritus Zonation Not as obvious Burrowing Higher up the sand is drier Crustaceans Really hard to tell on mud flats where the tide line is fuzzy due to low slope