Because of this, the communities are constantly changing. On rocky coasts, the zone is stratified vertically. Where only the highest tides reach, there are only a few species of algae and mollusks.
In those areas usually submerged during high tide, there is a more diverse array of algae and small animals, such as herbivorous snails, crabs, sea stars, and small fishes.
At the bottom of the intertidal zone, which is only exposed during the lowest tides, many invertebrates, fishes, and seaweed can be found. The intertidal zone on sandier shores is not as stratified as in the rocky areas. From left: mussels, worms, and a spider crab at a hydrocarbon seep community in the Gulf of Mexico; a sea fan and brain coral in the Florida Keys National Marine Sanctuary; a school of Atlantic amberjack off North Carolina.
The pelagic zone includes those waters further from the land, basically the open ocean. The pelagic zone is generally cold though it is hard to give a general temperature range since, just like ponds and lakes, there is thermal stratification with a constant mixing of warm and cold ocean currents.
The flora in the pelagic zone include surface seaweeds. The fauna include many species of fish and some mammals, such as whales and dolphins. Many feed on the abundant plankton. The benthic zone is the area below the pelagic zone, but does not include the very deepest parts of the ocean see abyssal zone below.
Here temperature decreases as depth increases toward the abyssal zone, since light cannot penetrate through the deeper water. Algal blooms [Figure 5] can become so extensive that they reduce light penetration in water.
As a result, the lake or pond becomes aphotic and photosynthetic plants cannot survive. When the algae die and decompose, severe oxygen depletion of the water occurs. Fishes and other organisms that require oxygen are then more likely to die. Rivers and the narrower streams that feed into the rivers are continuously moving bodies of water that carry water from the source or headwater to the mouth at a lake or ocean.
Abiotic features of rivers and streams vary along the length of the river or stream. Streams begin at a point of origin referred to as source water. The source water is usually cold, low in nutrients, and clear.
The channel the width of the river or stream is narrower here than at any other place along the length of the river or stream. Headwater streams are of necessity at a higher elevation than the mouth of the river and often originate in regions with steep grades leading to higher flow rates than lower elevation stretches of the river.
Faster-moving water and the short distance from its origin results in minimal silt levels in headwater streams; therefore, the water is clear.
Photosynthesis here is mostly attributed to algae that are growing on rocks; the swift current inhibits the growth of phytoplankton. Photosynthesis may be further reduced by tree cover reaching over the narrow stream.
This shading also keeps temperatures lower. An additional input of energy can come from leaves or other organic material that falls into a river or stream from the trees and other plants that border the water. When the leaves decompose, the organic material and nutrients in the leaves are returned to the water. The leaves also support a food chain of invertebrates that eat them and are in turn eaten by predatory invertebrates and fish.
Plants and animals have adapted to this fast-moving water. For instance, leeches phylum Annelida have elongated bodies and suckers on both ends. These suckers attach to the substrate, keeping the leech anchored in place. In temperate regions, freshwater trout species phylum Chordata may be an important predator in these fast-moving and colder river and streams.
As the river or stream flows away from the source, the width of the channel gradually widens, the current slows, and the temperature characteristically increases. The increasing width results from the increased volume of water from more and more tributaries. Gradients are typically lower farther along the river, which accounts for the slowing flow. With increasing volume can come increased silt, and as the flow rate slows, the silt may settle, thus increasing the deposition of sediment.
Phytoplankton can also be suspended in slow-moving water. Therefore, the water will not be as clear as it is near the source. The water is also warmer as a result of longer exposure to sunlight and the absence of tree cover over wider expanses between banks. Worms phylum Annelida and insects phylum Arthropoda can be found burrowing into the mud. Predatory vertebrates phylum Chordata include waterfowl, frogs, and fishes.
In heavily silt-laden rivers, these predators must find food in the murky waters, and, unlike the trout in the clear waters at the source, these vertebrates cannot use vision as their primary sense to find food.
Instead, they are more likely to use taste or chemical cues to find prey. When a river reaches the ocean or a large lake, the water typically slows dramatically and any silt in the river water will settle. Rivers with high silt content discharging into oceans with minimal currents and wave action will build deltas, low-elevation areas of sand and mud, as the silt settles onto the ocean bottom.
Rivers with low silt content or in areas where ocean currents or wave action are high create estuarine areas where the fresh water and salt water mix.
Wetlands are environments in which the soil is either permanently or periodically saturated with water. Wetlands are different from lakes and ponds because wetlands exhibit a near continuous cover of emergent vegetation. There are several types of wetlands including marshes, swamps, bogs, mudflats, and salt marshes [Figure 7].
Freshwater marshes and swamps are characterized by slow and steady water flow. Bogs develop in depressions where water flow is low or nonexistent. Bogs usually occur in areas where there is a clay bottom with poor percolation. Percolation is the movement of water through the pores in the soil or rocks. The water found in a bog is stagnant and oxygen depleted because the oxygen that is used during the decomposition of organic matter is not replaced.
As the oxygen in the water is depleted, decomposition slows. This leads to organic acids and other acids building up and lowering the pH of the water. At a lower pH, nitrogen becomes unavailable to plants. This creates a challenge for plants because nitrogen is an important limiting resource. Some types of bog plants such as sundews, pitcher plants, and Venus flytraps capture insects and extract the nitrogen from their bodies.
But like the difference between a taiga biome and a savannah biome — the ocean is vastly different depending on where you go. The marine biome is the largest ecosystem on earth! But despite the vast expanse of marine life, there are three main types of marine biomes. Because the ocean is so large, we can examine oceanic habitats by looking at the marine biome zones, of which there are four. The intertidal zone is also called the littoral zone.
It can be underwater or exposed as the tide comes in or out, and this is where waves form and crash to shore.
Depending on the flow of the tide, the animals and lifeforms living in the intertidal zone can vary greatly. The intertidal zone occurs on shores all over the world, and due to the constant flux of incoming waves, it can be a tough place for organisms to survive. The pelagic marine biome is the open ocean, which you can see on the marine biome map above.
The pelagic marine biome consists of three main layers, which are based on how much light can enter that habitat. These are:. The coral reef biome is one of the most beautiful places you can find in the world! Coral reefs are found in warm, tropical waters, and they exist in shallow waters up to feet as they rely on sunlight to survive. There are three main types of coral reef biomes:. Pollution is also harming the marine ecosystem. Pollutants, such as fertilizers and household products that are put down the drain make their way through streams and rivers into estuaries , and eventually to the ocean where they badly disrupt the ecosystem and can cause harm to sea life.
Oil spills are also a large source of pollution in the oceans. Many organizations and people are currently trying to help protect and clean our oceans. There are many simple things that you can do to help protect the ocean.
Also, cut all of your 6 pack rings before you throw them away. This will keep sea creatures from getting caught in the plastic rings. Lastly, learn more about the ocean. With knowledge and understandingyou will be able to help save our threatened oceans. American Museum of Natural History Expeditions. Discovery School Planet Ocean. Dive and Discover. EPA - Marine Ecosystems. Monterey Bay Aquarium. Museum of Science - Ocean's Alive. Ocean Alliance - Voyage of the Odyssey.
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