Intertidal Zone

What types of communities are found in the intertidal zone?

seastars, seaweeds, snails, etc. (mix of various classes of invertebrates and vertebrates, all adapted to withstand changing conditions)

The types of communities that occur in the intertidal zone are profoundly influenced by the type of what? Example?

Substrate (ex: rock)

Tides were first mathematically described by ____

Sir Issac Newton

What does substrate do?

Influences the types of communities that occur in the intertidal zone

Our tides are dominated by which celestial body?

Moon

A tidal pattern with one high tide and one low tide every 24 hours is called what? Where are some places these tides can occur?

A diurnal tide. The Gulf of Mexico, the java sea

A tidal pattern with two high tides of similar amplitude and two low tides of similar amplitude every 24h is termed what? where can these be found?

A semidiurnal tide. The east coast of America, the west coast of Africa

A tidal pattern with two unequal high tides and two unequal low tides every 24 h is termed a what? Where can these occur?

A mixed or mixed semidiurnal tide. Along the pacific coast of north America, in some areas in the Gulf of Mexico.

On a rocky intertidal coast, stresses and exposure would be greatest for organisms living in the what?

Upper zone

What organisms live in the upper zone?

phytoplankton, sharks, tuna, etc.

Stresses imposed by low tide in the rocky intertidal include

Water loss, temperature, salinity, inability to feed, inability to respire

Non-mobile organisms exposed to low tide must do what?

Tolerate the stress

Unlike non-mobile organisms, mobile organisms can move. Given this advantage, what do they do when it comes to low tides?

Avoid low tides

Depressions, cracks, and aggregations of animals can provide what to marine organisms?

A more favorable Microclimate

On the rocky intertidal, most organisms are what kind of feeders? What are examples of these animals?

Filter feeders. (Ex: Mussels, barnacles, sea squirts)

The most limiting factor on rocky intertidal coasts is usually what?

Space

Vertical zonation is usually due to a combination of what?

Behavioral and physical factors

Example of behavioral and physical factors in Vertical Zonation?

Physical: Wave action and moisture, Behavioral: The ability to withstand exposure and cling to surfaces

________________ are an important keystone predator in the rocky intertidal.

Seastars

The greatest biodiversity is found at a ____________________ level of disturbance.

Moderate or intermediate

What factors are generally limiting in the upper rocky intertidal?

Physical

What factors are generally limiting in the lower rocky intertidal?

Biological

What is a biological factor example in marine organisms?

Competition for food, mates, space, etc.

In soft bottom intertidal communities, the presence of coarse sediments would indicate that the currents above them are ______

Strong

Fine sediments are typically rich in what?

Organic matter

Animals that disturb the sediments

Bioturbators

Examples of marine bioturbators?

Sea cucumbers, rays, ghost shrimp

In soft sediments with fine particles, what type of feeding is common?

Deposit

Examples of deposit feeders in soft sediments with fine particles

Lugworms, some bivalves, and some crustaceans