Intertidal Pool The area where the land meets the sea, it is alternatively submerged and exposed by the daily cycle of tides. The resident organisms are subject to huge daily variation in temperature, light intensity, and availability of seawater, which makes life difficult.
Intertidal Zonation Four Main Zones Splash Zones : The splash zone is never covered by water and is only sprayed with saltwater during high tides. High Intertidal Zone: The high tide zone is covered with saltwater only during high tides Middle Intertidal Zone: The mid tide zone is covered and uncovered twice a day by the tides Low Intertidal Zone: The low tide zone is only uncovered during the lowest of tides
What Causes the Tide? Tides are created by the gravitational pull of the moon and, to a lesser extent the sun, upon the Earths oceans. The sun has about half the effect that the moon has on the Earths tides. In most areas, typically two high tides and two low tides occur within a 24 hour and 50-minute lunar day. (A lunar day is 50 minutes longer than a solar day.) The time between each high and low tide (or low and high tide) is 6 hours and 12.5 minutes.
Abiotic FactorsTemperature The temperature of tide pools is affected by air temperature and direct sunlight on the pool.Salinity The sun and wind evaporate water from the surface of pools. In isolated tide pools, this caused an increase in salinity (salt concentration).
Abiotic FactorsWind It increases heat loss by evaporation and convection. It also contributes to water loss in organisms by increasing the rate of evaporation in animals and transpiration in plants.Light Most aquatic plants and algae are limited to a fairy narrow zone close to the surface , where light is sufficient to allow photosynthesisMoisture Without moisture there can be no life. Water acts as a solvent for chemical reactions, takes part in the reactions of hydrolysis.
Zone 3: Middle Tide Zone The approximate limits of this zone may be recognized by the development of mussel beds at the upper level and the patches of the surf grass at its lower level. More favorable for many species, and the major biological factor at work is the competition for space. Increased submergence time.
Zone 4: Low Tide Zone Mostly submerged in water. More marine vegetation. Organism in this area are not well adopted to periods of dryness and temperature extremes. Creatures in this area can grow larger sizes because there is more available energy available.. Water is shallow enough to allow plenty of light to allow substantial photosynthesis. The area is also protected from large predators such as large fish because of the wave action and water being shallow.
AdvantagesThere are a number of advantages to living in a tide pool ecosystem. • Algae and other intertidal plants grow in the abundant sunlight and support an entire food chain of animals. • Constant wave action supplies the tide pool with nutrients and oxygen. • Food is abundant. • A varied substrate provides hiding places and surfaces to cling to.
Challenges to Living in theIntertidal Zone The rapidly changing conditions of a tide pool make survival a challenge. Exposure to surf and sun varies considerably. • Plentiful sunlight, which helps intertidal plant life grow quickly, can also rapidly dry up precious moisture and increase the water temperature. • As the tides rise and fall, the salinity (salt concentration) constantly changes. Animals living in the intertidal zone must be able to tolerate wide salinity variations.
Challenges to Living in theIntertidal Zone • If sufficient nutrients are available, intertidal animals reproduce rapidly, so they constantly compete for space, light, and food. • Animals are also exposed to predators while the tide is out. • Waves that bring in much-needed nutrients and moisture can also carry unprotected animals out to sea.
Adaptations Small animals that live in the splash zone can avoid desiccation by closing their shells tightly to seal in moisture. The strong pounding of waves caused a major problem. Some, like sea stars, cling fast to the rocky surfaces; others find shelter in crevices or hide under thick mats of seaweed when the tide is out. Some species may eviscerate. Some animals secrete a glue-like mucus to stick to the rocks surface. Many fishes that inhabit tide pools, such a sculpin and young opaleyes, can breathe air at the surface