Rocky Intertidal
By Taylor Marshall and Ali Bland
Overview:
Organisms:
The rocky intertidal area has three different zones where organisms may be found. The upper intertidal zone, mid-intertidal zone, and the low intertidal zone. The upper zone is usually dry unless a storm comes in or an extremely high tide occurs. Limpets, barnacles, lice, whelks, lichens and isopods are found in this area. The mid-intertidal zone consists of an upper and lower region, and during high tide, the upper region becomes flooded. Many organisms found in this region such as barnacles, chitons, crabs, sea stars, snails, muscles, whelks, brittle stars limpets, and isopods. The lower region is flooded twice a day because of the regular tide coming in. Many of the same organisms are found here, but anemones, sea lettuce, sea palms, and sponges occur here as well. In the low-intertidal zone, it is unusual for the area to be exposed to the open air. It is only uncovered when the tide becomes extremely low. All of the organisms in the previous zones occur here along with abalones, brown seaweed, hydroids, shrimp, sea urchins, and other small organisms that cannot handle dry conditions. Tidal organisms are preyed upon by marine animals such as fish, while submerged, and land animals like birds while they are exposed.
Food Chains:
The existing food chains in the tide pools of rocky shorelines are very diverse. There are both plant and animal life that attribute to the environments food chain. Organisms in these chains can be as small as zooplankton and as large an otter, or anything in-between. At the base of the food chain are algae and the other marine plants. Abalones, limpets and turban snails have the ability to smell ochre stars, and move away before they are eaten. Because tidal pools lie on the edges of oceans, many different types of animals may rely on them as a food source. For example, gulls and other sea birds feed on the fish nurseries that often lie exposed in tide pools.
Although the conditions are constantly changing, there are advantages to living in this environment. The rocky intertidal zone has many spots organisms can find shelter or hide in. The surface of the rocks also give organisms a good place to attach. Oxygen and nutrients are abundant in tide pools because of the waves continuously flooding into them. The amount of sunlight and food in the rocky intertidal zone is very high. Some of the struggles of living there are that the organisms are exposed while not under water to predators and also have a potential of losing their moisture as the sun evaporates the water quickly because of the abundance of sun exposure. The waves can carry organisms out to sea if they are not attache properly to the rocks. Also the change in salinity, as mentioned earlier, is another challenge. Since nutrients are so abundant, organisms must compete for light, space, and food constantly. Organisms must adapt if they want to survive in this extreme environment. To avoid loosing moisture some organisms fasten their shells so that moisture is locked in. Others have thicker shells to slow the evaporation of water. Organisms also find ways to adhere to the rocks or locate shelter in the rocks so they do not get swept away by the crashing waves. Fish are able to survive in the low-intertidal zone when it's not exposed to the air. This is because the plants provide protection and food for them. Overall this environment requires special adaptations to survive the harsh conditions.
Works Cited
- Ecosystems: Rocky Intertidal Ecosystems . 8 March 2016 <http://oceanspaces.org/monitoring/ecosystems/rocky-intertidal-ecosystems>.
- Intertidal Ecology . 8 March 2016 <https://seaworld.org/Animal-Info/Ecosystem-InfoBooks/Tide-Pools/Intertidal-Ecology>.
- The Intertidal Zone. 8 March 2016 <http://www.enchantedlearning.com/subjects/ocean/Intertidal.shtml>.
Photos
- http://www.enchantedlearning.com/subjects/ocean/Intertidal.shtm
- http://science.kennesaw.edu/~jdirnber/oceanography/LecuturesOceanogr/LecRockyIntertidal/waves.jpg
- http://tidepooling.typepad.com/tidepooling_on_the_southe/images/stars_mussels_adjusted.jpg
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