Question

In: Biology

Describe the main zoning levels of organisms on sandy coasts.

Describe the main zoning levels of organisms on sandy coasts.

Solutions

Expert Solution

Sandy coasts or shores are those coasts that are dominated by sand size sediments and are formed as a function of both sand sources and coastal processes. Sandy coasts generally lack a proper pattern of vertical zonation and apparently appear barren and devoid of life. The most important factor determining the distribution of organisms in this habitat is the wave action. Although it is much less defined as compared to other habitats, zonation does exist on sandy coasts. A typical sandy coasts can be divided into three zones: supralittoral, midlittoral and infralittoral (subtidal) zones. These zones are discussed as follows:

(i) Supralittoral zone- It stretches from the high tide to the point of terrestrial vegetation origin. Sand dunes cover the top most layer of this zone and much of this area is unsuitable for habitation as the scorching heat of the sun bakes the surface continuously, raising its temperature and drying it. Just below this level is a zone of drying sand which remain moistened only during the high tides and most of the organisms inhabiting in this zone are termed infauna because they burrow in the sand to escape the dry periods and intense heat of the sun. They obtain oxygen and other nourishments through their skin or gills that draws water by an elaborate mechanism via siphons. The dominant macroorganisms of the supralittoral zone of temperate regions include insects, isopods and crustaceans (beach hoppers). In the tropics or warmer parts of temperate region, there is a slight difference, as the beach hoppers are replaced by Ghost crabs (Ocypodinae) and fiddler crabs (Uca).

(ii) Midlittoral zone- Most inhabitants of this zone are burrowers. During high tides, they emerge from their burrows in search of food, to find mate and reproduce or sometimes, they extend their appendages to filter out desired nutrients and oxygen from the water. During low tide, they return back to their burrow into the moist sand. The midlittoral zone also exhibit vertical zonation. The dry sand and drying sand are less stretched as compared to supralittoral zone. Just below the drying sand, there is a zone of retention that retains moisture at low tide due to capillary action of water. This zone is inhabited by various isopod crustaceans. This zone is followed by zones of resurgence and saturation which are closer to sea. In the zone of resurgence, water is retained down the surface and provide supports to a variety of assorted crustaceans and polychaete worms. Farther down is the zone of saturation which is highly diversified and supports a wide range of organisms. It contains maximum water content. Burrowing animals like polychaete, bivalves like coquinas, tellins and venus clams are found in this region alongwith some amphipods and other small crustaceans. The sandy bottom part also reveals the presence of echinoderms like sand sea star. Moon snails and olive snails are common in this habitat and they leave a trail while crawling along the bottom of the sand. Another prominent organism found in this habitat is the lungworm. This are deposit feeders and digest the organic matter present in sand.

(iii) Infralittoral zone- The infralittoral or subtidal zone is a truly marine environment where the variety and distribution of organisms depends on the characteristics of the bottom sediments. Where the bottom sedimets exposes barren sands only. the organisms are predominantly burrowing in nature, similar to those inhabiting the midlittoral zone. Several species of bivalves, tube worms, and other polychaete either filter food particles or search sand particles for detritus. This regions also contains animals like heart urchins that move slowly along the sandy bottom feeding on the detritus mixed with sand particles. In addition to arthropods and molluscs, the sandy coasts of the subtidal zone reveals the presence of seagrass beds which host sea urchins, sea stars, sea cucumbers, brittle stars and anemones. The presence of coral and introduction of rocks increases the complexity and diversity of life at the bottom. As this zone exposed only during the lowest spring tide, many species of fishes are found here that occasionally move into the midlittoral zone at high tide in search of food. The activity in this zone remains relatively constant and pace of life remain undisturbed for most of the time.


Related Solutions

Explain some environmental factors that include the formation and maintenance of sandy coasts
Explain some environmental factors that include the formation and maintenance of sandy coasts
Describe the zoning laws?
Describe the zoning laws?
Describe the three main reasons why multicellular organisms need their cells to divide. Which of these...
Describe the three main reasons why multicellular organisms need their cells to divide. Which of these are accomplished by mitosis and which are accomplished by meiosis? In which types of cells do mitosis and meiosis each take place? Does either mitosis or meiosis change the number of chromosomes in a cell? Describe the structure of chromosomes. Define and distinguish the following terms: unduplicated (single-stranded) chromosome, duplicated (double-stranded) chromosome, chromatid, and centromere. What process needs to occur before any cell division...
There are various levels of ecology that can be used to study organisms and their interactions...
There are various levels of ecology that can be used to study organisms and their interactions with the environment. What type of ecologist would be likely to compare the numbers of Northern Sawwhet Owls that migrate through the Midwest as compared to the Northeast? Organismal Ecologist Population Ecologist Community Ecologist Ecosystems Ecologist Physiological Ecologist During migration, large flocks of shorebirds form in areas with high food density. Food is abundant and evenly distributed, yet shorebirds are found in a clumped...
9.Define personal property? 10. Describe the zoning laws. Business Law questions.
9.Define personal property? 10. Describe the zoning laws. Business Law questions.
In sexually reproducing organisms, there are three main sources of genetic variation.
In sexually reproducing organisms, there are three main sources of genetic variation. Explain two of these sources and briefly describe what it is and how it leads to genetic variation. 
Construct a food web and label the trophic levels given the following organisms found in a...
Construct a food web and label the trophic levels given the following organisms found in a standard tank: -Snails -Copepod -Water Mite -Colonial Green Algae -Rotifer -Euglena -Gloeotila
Explain the main zones of vertical distribution of organisms that characterize in the Ocean depths and...
Explain the main zones of vertical distribution of organisms that characterize in the Ocean depths and what is the main factor that influences their formation.
How would pH and DO levels affect which organisms are collected for DNA barcoding?
How would pH and DO levels affect which organisms are collected for DNA barcoding?
Describe how organisms are placed in the Three Domain (Woese-Fox) classification system vs how organisms are...
Describe how organisms are placed in the Three Domain (Woese-Fox) classification system vs how organisms are placed in the Five Kingdom (Traditional Wittaker) classification system. Which classification system is more useful to a microbiologist and why?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT