Intertidal Ecology Concepts

These flashcards cover key concepts related to intertidal ecology, including definitions, classifications, challenges, and mechanisms.

Intertidal

The area that is covered at high tide and exposed at low tide.

Substrate

The material organisms live on or in; can be hard (rocks, concrete) or soft (sand, mud).

Epifauna

Organisms that live on top of a substrate (e.g., snails, crabs, barnacles).

Infauna

Organisms that live buried within a substrate (e.g., worms, clams).

Sessile

Organisms that are attached and cannot move (e.g., barnacles).

Motile

Organisms that can move freely (e.g., crabs, snails).

Rocky Intertidal Formation

Formed by steep coastlines, high wave energy, little sediment, and newly formed/uplifted land.

Population Growth Limitation

Limited by physical stress (drying, temperature), competition for space, and predation in rocky intertidal zones.

Upper Intertidal Zone

Rarely underwater, very dry; organisms include lichens, snails, limpets.

Middle Intertidal Zone

Regularly wet/dry; organisms include barnacles, mussels, seaweed.

Lower Intertidal Zone

Mostly underwater; organisms include seaweed, fish, urchins, anemones.

Desiccation

A challenge in intertidal zones; organisms may hide in tide pools, close shells, or tolerate drying.

Wave Shock

The force of waves hitting organisms; stronger at headlands, weaker in bays.

Zonation

The arrangement of organisms in intertidal zones, determined by physical tolerance and competition.

Keystone Species

A species that plays a critical role in maintaining the structure of an ecosystem (e.g., ochre stars control mussel populations).

Competitive Exclusion

When one species outcompetes and eliminates another species.

Ecological Succession

The process of regrowth following a disturbance; includes stages from bacteria/algae to barnacles and mussels.

Intermediate Disturbance Hypothesis

Moderate disturbance leads to the highest diversity; too little disturbance leads to dominance by one species.

Sediment Type Control

Controlled by water movement and sediment supply; fast water carries larger particles (sand/pebbles), slow water carries smaller particles (mud).

Grain Size and Water Retention

Small grains (mud) hold more water, while large grains (sand) drain quickly.

Low Oxygen Challenges

Challenges in soft-bottom intertidal include desiccation, low oxygen, and low primary production.

Anoxic Sediments Indicators

Sediments are anoxic when they appear black and have a rotten egg smell (due to hydrogen sulfide).

Food Sources in Intertidal

Three food sources include organic matter in sediment (most common), plankton, and diatoms.

Feeding Mechanisms

Deposit feeders eat sediment and digest organic matter, while suspension feeders catch particles from the water.

Zonation in Soft-Bottom Intertidal

Determined by how long the sediment remains wet or saturated with water.