Rocky Shore Ecology: Holbeck Beach This study was conducted to deduce whether the height to width ratio of limpets altered across the three main zones on the shore: upper, middle and lower. It was carried out on Holbeck Beach, North Yorkshire, where limpets were measured in all three zones using random sampling. We found a significant difference in the height to width ratio between the upper and lower shore and upper and middle shore. This is due to many factors, including the threat of desiccation and strong waves. Limpet Patelle VulgataRocky ShoreEcologyHolbeck Beach
Upper ShoreMiddle ShoreLower ShoreCallipers QuadrentRandom SampleDesiccation INTRODUCTION Common limpets, Patella Vulgata, are found, on rocky shores, wherever there is an area firm enough for attachment on rocks, stones and in rock pools. [1] The common limpet is commonly found on Holbeck shore in relatively high abundance. Patella vulgata are in the taxonomic group gastropoda, and the family acmaeidae. They are abundant on rocky shores of all degrees of wave exposure but a high density of seaweed makes it harder for the Patella Vulgata to attach itself to the rocks, so limpet density is reduced. 2] Patella Vulgata have the ability to use their mucus and their ‘foot’ to clamp down upon the rock with considerable force. This allows them to remain safely attached at all times, despite strong wave action and the threat of desiccation during low tide. When the limpet is fully clamped onto the rock it is almost impossible to remove them. The common limpet is a temperate species, so is found mainly across Europe, spread from Norway to Portugal. The grey conical shell of Patella Vulgata can reach a width of 6cm and height of 3cm with ridges radiating from the central apex.
The muscular foot of the limpet is usually a yellow colour and attached to the smooth interior of its shell. [3] Limpets graze upon algae, which grows upon the rocks where they live. They can scrape the algae with its radula (a tongue coated with many rows of teeth) as they slowly move across the rock surfaces. The Patella Vulgata always return to the same spot, known as the homing scar, before the tide withdraws. The shells grow to match the contours of the rock in order to form a strong seal, protecting them from desiccation and also predation.
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They find their way back to the same spot by using chemical cues, finding their own mucus track and following it back to their home point. [4] Limpets are the prey of a variety of creatures, including seals, fish, shore-birds, starfish and humans. The limpets have two defences: fleeing or clamping down to the rock. They can determine which would be the most effective by detecting chemicals in the environment. Patella Vulgata have the general lifep of 10 years but this can be drastically changed by the rate of growth. If there is an excess of food, the limpets grow exceedingly quickly but generally only live for around 3 years.
However, if food is sparse, limpets usually grow very slowly but can live up to 20 years. [5] Patella Vulgata are hermaphrodites and undergo a sex change during their life. At around 9 months they mature as males, but after a couple of years they change sex and become female. Spawning occurs annually, usually during the winter months as it is triggered by rough seas, which disperse the eggs and sperm. [6] The larvae has a pelagic life of about 2 weeks and then settles on rocks at a shell length of about 0. 2 mm, usually in rock pools or areas that are constantly damp. HYPOTHESIS
Our hypothesis states that there will be a difference in the height to width ratio of limpets on different parts of the beach: lower, middle and upper. The null hypothesis states that there will be no difference between the height to width ratio of limpets on different parts of the beach: lower, middle and upper. METHOD We visited an exposed rocky shore at Scarborough in order to deduce whether the height to length ratio of limpets changed across different zones of the shore. Initially, we had to identify the different area of the beach and we did this by using different types of seaweed and levels of diversity as an indicator. 7] The upper zone, also known as the high tide zone, does not have enough water to sustain large amounts of vegetation. [8] The predominant organisms are anemones, barnacles, hermit crabs and limpets. The rock pools in this area are inhabited by large seaweed and small fish. The middle shore, or middle tide zone, is submerged by water for approximately half of the cycle. This means that there is the capability to support much more marine vegetation, specifically seaweeds. The organisms found there are more complex and larger in size than further up the shore. 9] The rock pools can provide a suitable habitat for small fish, sea urchins, shrimps and zoo plankton. This area is more diversified than the upper shore. The lower shore, or low tide zone, is mostly submerged underwater. The most noticeable difference of this sub-region is the large diversity of different types of seaweeds. Organisms found in this zone are generally less adapted to periods of dryness. The creatures are generally the largest and most complex organisms on the shore as there are more sources of food as marine vegetation flourishes.
The way that we sampled was random, meaning that every point is equally likely to be selected, and selection of one point does not change the probability of including any other point. [10] Once we had deduced the zones, we picked a random point in the zone, which was always the origin, and used a random number chart to decide how we far would walk before putting down the quadrant. We then measured the height and width of all the limpets inside the quadrant. In order to measure the limpets accurately we used a set of callipers; the callipers were positioned from the posterior end of the shell to the anterior.
On average we measured 27 limpets per zone. We did not calculate a running mean but we knew from other students that variation decreases in the region of 20-25. We collected the data using a simple tally, adding to it during the day. RESULTS Lower to Middle Shore My hypothesis was that there would be a significant difference in the height to length ratio of limpets found between the lower and mid shore. My statistical test gave a t-value of 1. 3 at 52 degrees of freedom. This value is not large enough to give me any confidence that there is a statistically significant difference, as it is below 1. 8; therefore I must reject my hypothesis and accept my null hypothesis that there is no significant difference between the height to length ratio of limpets found between the lower and mid shore. Middle to Upper Shore My hypothesis was that there would be a significant difference in the height to length ratio of limpets found between the mid and upper shore. My statistical test gave a t-value of 3. 3 at 50 degrees of freedom. This value is larger than 2. 70, giving me a 99% confidence that there is a statistically significant difference and therefore I am able to accept my hypothesis. Upper to Lower Shore
My hypothesis was that there would be a significant difference in the height to length ratio of limpets found between the upper and lower shore. My statistical test gave a t-value of 3. 2 at 52 degrees of freedom. This value is again larger than 2. 70 giving me a 99% confidence that there is a statistically significant difference and therefore I am able to accept my hypothesis. CONCLUSIONS The data we collected shows that the smallest limpets found on the Holbeck shore were on the middle shore. We found that, on the lower shore, the limpets had the smallest height but the largest width.
This can be explained as they are the affected most by strong waves and are most at risk of being washed away. To combat these problems they have a shallow but wide shell to give the largest area for the muscular foot to hold onto the rock. Also, the limpets at the bottom of the shore are underwater for the longest time. This means that they have less problems combating desiccation than limpets in the other zones. This allows for a larger circumference of the shell, as it is not as essential to have a perfect seal to the rock. [11]
On the upper shore, the limpets we found were generally taller with a smaller base of their shell. Being far up the beach, they do not have as many strong waves which may wash them from their rock so they do not need as large an area for the muscular foot to grip the rock. However, the smaller circumference lowers the chances of having an imperfection in the shape of the shell compared to the homing scar, meaning that a perfect seal will be created. This is of paramount importance as they spend most of their time exposed and in the sunlight – meaning desiccation could easily occur. 12] To help prevent desiccation, the tall shell allows water to be trapped inside, creating a small pool and allowing the limpet to survive whilst being out of water during low tide. FURTHER DISCUSSION Apart from the threats of desiccation and strong waves, there may be other factors which influence the growth of limpets in different areas on the shore. One factor would be the feeding time available for limpets. [13] Limpets further down the shore spend more time underwater so they have more time to graze where as the limpets further up the shore have very little time under water so have very little grazing time. 14] The amount food eaten may in some way affect the growth patterns and development of the conical shells. Another factor is salinity. When the shore is submerged regularly by sea water, the salinity generally remains stable. However, in areas with an abundance of rock pools may have varied salinity levels. As rock pools constantly dry out, due to exposure to warm temperature, the water evaporates leaving behind the salt. [15] Overtime the salinity levels become high, making the rock pool inhabitable to many creatures, including limpets which can only tolerate normal sea water salinity. 16] Fluctuations in salinity alter the water potential and may cause cells in the limpet to become turgid or flaccid – both of which are dangerous. REFERENCES [1] – RG Evans (1974). Biology of British Limpets: Page 411. Found on 12. 10. 12. [2] – I Cockcroft. Website: Gyllybeach, Common Limpet. Found on 13. 10. 12. [3] - Fish, J. D. & Fish, S. (1996) A student's guide to the seashore. Second Edition. Cambridge University Press, Cambridge. Found on 13. 10. 12 [4] – Website: pznow, Limpets. Found on 14. 10. 12. [5] - Hill, J. M. , (2000). Patella vulgata.
Common limpet. Marine Life Information. Found on 17. 10. 12 [6] – BBC (2005) Website: BBC, Science and Nature, Animal Fact Files, Common Limpet. Found on 12. 10. 12. [7] – Vipera, T. Website: Life Under The Sea, Zonation. Found on 18. 10. 12. [8] – YPTE (2010). Website: ypte, Environment, Rocky Shore Ecology. Found on 15. 10. 12. [9] – Rothery M (2005) Rocky Shore Handout. Found on 20. 10. 12. [10] – R Easton, Hall J. Website: Stats Glossary, Sampling. Found on 18. 10. 12. [11] – Norfolk WT (2011). Website: Norfolk Wildlife Trust, Wildlife, Common Limpet. Found on 20. 0. 12. [12] – J Adams (1999) "A Comparison of Width and Height of Common Limpets Between a Sheltered Shore and an Exposed Shore.. Found on 20. 10. 12. [13] - Levinton J. S. (1995) Marine biology: function, biodiversity, ecology. Oxford University Press. Found on 22. 10. 12 [14] - Bennett, I. (1987) W. J. Dakin's classic study: Australian Seashores. , Angus & Robertson, Sydney. Found on 22. 10. 12. [15] – Wars (2011). Website: Limpet Wars, marine science. Found on 20. 10. 12. [16] - Knox G. A. (2001) The ecology of seashores. CRC Press. Page 557. Found on 20. 10. 12
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FAQs
Does shore height affect limpet size? ›
Limpet body size increased with increasing tidal height. This increase in size with tidal height was correlated with exposure to wave splash and migratory behavior.
What is the average size of a limpet? ›1. Common limpets grow to a maximum length of 2.4 inches (6 cm), with females typically growing larger than males. 2. Common limpets living under algae live only 2 to 3 years, whereas those living on bare rocks may live up to 16 years.
What zone do limpets live in? ›Limpets (Notoacmea, Collisella) are small, cone shaped shells found on rocks throughout the intertidal zone.
Why limpets may be different sizes at the lower shore compared with the upper shore? ›In general terms, the variation was explained mainly by shell height (Fig. 1b), with the upper shore showing less variable shell shape than the middle and lower shores.
Why are limpets larger in Upper shore? ›This is said to be because on exposed shores the limpet's muscles are more often contracted so it can hold on better so the shell grows up rather than out. Shell shape in limpets is much more complicated than that though and the results of investigations of this are very variable.
How do limpets adapt to the intertidal zone? ›Limpets have adapted to survive the intertidal zones of the rocky shore. Their strong foot muscle attaches the shell to rocks, preventing desiccation at low tide, and anchors the animal in rough seas.
How do you measure limpets? ›- Mark the boundaries of the permanent area with meter tapes or cones.
- In teams of two or three, systematically search the whole area.
- Designate one person as the recorder. ...
- Use rulers (or if in a crack, cable ties or paper clips) to measure the length of the individual.
As its name alludes, Lottia gigantea is the largest growing limpet in North America. This conspicuous marine snail can be found clinging to the bedrock and boulders of the Pacific shores and adjacent islands, from Bahia del Tortuga in Baja California, Mexico north to Neah Bay, Washington.
What conditions do limpets like? ›Limpets live in both freshwater and marine habitats. The marine habitat occupied by the limpets in the study is the intertidal zone, but other marine limpets live in deeper water. Some species even live in deep-sea hydrothermal vents.
Do limpets need water? ›This is drawn in to the gills via a hole above the head. When the tide goes out they have a problem with the lack of water. They clamp down and reduce their metabolism which in turn reduces the need for water. The shell has a high degree of waterproofing to conserve water.
How fast do limpets grow? ›
| Typical abundance | High density |
|---|---|
| Female size range | Small-medium(3-10cm) |
| Female size at maturity | |
| Growth form | |
| Growth rate | 2mm/month |
Both salinity and species significantly affected the survival of the limpets over the 96 hours. Survival was highest in salinities close to those of normal seawater, and greatly reduced in the hypo saline waters.
Why do limpets stick to rocks? ›The limpet sticks itself very tightly to rocks on the seashore to protect itself from drying out, from being washed away and from being eaten by predators such as the oystercatcher or dog whelk.
What do limpets do during high tide? ›They use their one, muscular foot to cling to rocks to stay in place and keep cool when they are exposed during low tide and then move around and eat algae when their rocks are submerged during high tide.
What is the importance of limpet? ›Limpets are significant grazers on rocky shores around the world and heavy grazing can prevent algal colonization, resulting in a patchy cover of seaweeds and a greater diversity of microhabitats (Fig. 6.7).
How does wave exposure affect the growth of the limpets? ›Small spatial scale effects of wave action were not observed for limpet size, but consistently led individuals to proportionally large feet in the exposed boulder side for all three shores, and more conical shells in the exposed boulder side in Fazenda shore.
Why are limpets found on the middle shore? ›The middle parts of exposed shores are often dominated by species which are capable of holding on tight against the wave action and withstanding the heat of the sun and the drying of the wind. Limpets and barnacles are two such creatures and they sometimes dominate the middle parts of exposed shores.
How does a limpet adapt to temperature? ›On thermally stressful rocky shores, small, slow-moving ectotherms such as limpets exhibit morphological characteristics such as high-spired and heavily ridged shells which may reduce the likelihood of reaching stressful or lethal body temperatures.
What are 2 adaptations shown by organisms that inhabit the intertidal zone? ›Barnacles, mussels, and kelps can survive in this environment by anchoring themselves to the rocks. Barnacles and mussels can also hold seawater in their closed shells to keep from drying out during low tide.
Do limpets live in the splash zone? ›Limpets have a planktonic larval form, like periwinkle snails, that develops from the fertilized egg. These limpets share the lower reaches of the Splash Zone with millions of tiny barnacles.
What is the shell pattern of limpet? ›
Limpets shell has a continuous pattern with color ranging from pure white to dark tan. They either attached to white gooseneck barnacles or to tan colored rocks. The light-colored limpets camouflaged with white barnacles while tanned limpets camouflaged on tan-colored rocks.
What are the identifying features of limpet? ›The common limpet has a greyish, conical shell and is slightly larger than the other two. The Black-Footed Limpet has a smaller flatter shell and is mainly found around the south of the country. The China limpet has an orange patch on the inside of its shell.
How many types of limpets are there? › What is the common limpet called? ›Patella vulgata, common name the common limpet or common European limpet is a species of sea snail.
Why are limpets so strong? ›There is a high volume of the mineral goethite, an iron oxyhydroxide, in the teeth compared to the volume of protein polymer. What's more, the goethite nanofibres are incredibly small in diameter, and so are smaller than the critical size above which the fibres could be prone to defects which could make them weaker.
How strong is a limpet? ›A limpet eats by scraping algae off rocks with tiny teeth on its tongue. It turns out that limpet tooth material can be as much as thirteen times as strong as ordinary steel. If we could make it into a 1/16th inch wire, that wire could lift an automobile.
What eats a limpet? ›Limpets are preyed upon by a variety of organisms, including starfish, predatory gastropods, shore-birds, fish, lizards, small mammals, seals, and humans. Oystercatchers and other shore birds can be especially voracious predators (Lindberg 2004).
What eats the common limpet? ›The only fish which eats the common limpet is the wrasse, as they have the powerful jaws needed to wrench limpets off rocks and consume the flesh inside.
Is limpet good or bad? ›Some limpet species are herbivores and are beneficial to even a reef aquarium. But even the herbivores can become harmful if there is not enough food for them in the aquarium.
Can limpets survive in freshwater? ›The freshwater limpet is called Latia. They live in clean running streams and rivers. The tiny limpet feeds by scraping algae off the stones and rocks at the bottom of the water body. For this it uses a radula, a strap-like tongue with rows of teeth.
What do limpets live on? ›
Limpets are often found in dense groups on intertidal rock platforms feeding on algae.
Are limpets male or female? ›Most limpet species are hermaphrodites, possessing both male and female characteristics, and change sex at one point in their lives, often due to external environmental factors.
Can limpets bite you? ›Typically, its teeth are so small that this rasping is unlikely to break your skin and create a wound. The limpet, who enjoys feasting upon algae growing atop sea rocks, is virtually harmless to humans.
Are limpets freshwater or saltwater? ›Though it sometimes originates from brackish and marine environments, the Marbled Limpet Nerite Snail is highly adaptable to fresh and brackish water. It is widely believed that it spawns in brackish or marine environments and spends the majority of the rest of its time in freshwater.
Do limpets need air? ›Most marine limpets have gills, whereas all freshwater limpets and a few marine limpets have a mantle cavity adapted to breathe air and function as a lung (and in some cases again adapted to absorb oxygen from water).
Do freshwater limpets eat plants? ›They consume the fish waste and plant remains helping aquarists to maintain good water conditions. Fortunately limpets don't eat live plants which should calm down the owners of the planted tanks.
How do limpets avoid drying out? ›Limpets have a strong muscular foot which allows them to hold on tightly to rocks. At low tide, the limpet will clamp its shell down tight to prevent itself from losing water and drying out.
How does pH affect limpets? ›Greater concentrations of acid resulted in a pH change in the seawater which affected limpet motility; limpet movement was inhibited by seawater of pH 5.5, and at pH 2.5 limpets became immobile.
How do humans affect limpets? ›Patellid limpets are also subjected to anthropogenic impacts on the coastal ecosystems such as, pollution, habitat removal, and harvest which in some cases has led to the reduction of abundance or even the disappearance of limpets from large areas.
What impact do limpets have on the environment? ›In these experiments, it was the key job performed by the main herbivore (limpets) that helped the ecosystems stay resilient in the face of warming. Limpets are voracious consumers of algae, and their action prevents algae from building up and using all the available space – a valuable resource on rocky shores.
What factors affect the size of limpets? ›
Limpet body size increased with increasing tidal height. This increase in size with tidal height was correlated with exposure to wave splash and migratory behavior.
Is limpet teeth stronger than diamond? ›"We were quite happy that the limpet teeth exceeded that." The teeth are so strong, it turns out, that they outdo Kevlar and roughly match the pressure required to turn carbon into diamond below the Earth's crust.
Can you eat rock limpets? ›Can you eat a limpet raw? The common limpet is edible and can be eaten raw, but you're probably going to want to cook it. Check that the limpet is still alive, especially if it has been a while since collection. You will see it moving, so it's not hard to check this.
How do you remove limpets from rocks? ›Limpets are often overlooked and overcooked! If you want to eat limpets, first knock them off the rock in one swift move. If they are stuck fast, don't continue to hit, just move on. If you have damaged their shell, then it is best to harvest them as they will be vulnerable to predators, etc.
Can you eat limpets during red tide? ›there is limited data regarding whether eating limpets during a red tide could cause PSP poisoning. But it seems that since there are not filter feeders, toxins do not build up in their tissue as with mussels and other shellfish.
How does the height of the tide impact the types of organisms that can live in the intertidal zone? ›Organisms that live in the intertidal zone tend to form their own communities across the zone's elevation gradient. Some species live further up the shore and closer to the high tide line, while others live further down the shore, closer the low tide line.
Do limpets live in shallow water? ›The Common Limpet, also referred to by its scientific name of Patella vulgata, is a cone-shaped sea snail species. It lives in the shallow water along the rocks on the shore of Western Europe.
What causes a wave to increase in height and speed as it approaches the shore? ›As wind-driven waves approach the shore, friction between the sea floor and the water causes the water to form increasingly steep angles. Waves that become too steep and unstable are termed “breakers” or “breaking waves.”
What do waves increase in height as they approach the shore? ›When the wave touches the bottom, friction causes the wave to slow down. As one wave slows down, the one behind it catches up to it, thus decreasing the wavelength. However, the wave still contains the same amount of energy, so while the wavelength decreases, the wave height increases.
What happens to wave height as it reaches the shore? ›Breaking Waves - As a wave nears the shore, its base encounters frictional resistance by the sea floor. This causes the height of the wave to increase and the wavelength to decrease. A breaker is a wave that has become so steep that the crest of the wave topples forward, moving faster than the main body of the wave.
What temperature do limpets live in? ›
The rocky intertidal zone features some of the most extreme thermal conditions on the planet, and the global distribution of limpets spans habitats from arctic sites that drop to well below freezing during the winter to tropical sites where rock temperatures can exceed 50 °C.
Does red tide affect limpets? ›there is limited data regarding whether eating limpets during a red tide could cause PSP poisoning. But it seems that since there are not filter feeders, toxins do not build up in their tissue as with mussels and other shellfish.
Why does the size of high and low tides change depending on location? ›Because the moon follows an elliptical path around the Earth, the distance between them varies by about 31,000 miles over the course of a month. Once a month, when the moon is closest to the Earth (at perigee), tide-generating forces are higher than usual, producing above-average ranges in the tides.
What is a tide where there is the greatest difference between high and low water levels? ›When all three are in line (around full and new moons), the combined effect of the moon's and sun's pull on the earth's water is at its greatest resulting in the greatest ranges between high and low tide. This called a "spring" tide (from the water springing or rising up).
What is a tide where there is the greatest difference between high and low water occurs during a new or full moon? ›Around each new moon and full moon – when the sun, Earth, and moon align in space – the range between high and low tides is greatest. These are the spring tides.
How do limpets survive out of water? ›It leaves a tiny gap around the edge of the shell, big enough to let oxygen in so it can breathe, but not big enough to let water escape. Limpets often wear away a patch on the rock where they sit which fits the shape of their shell exactly.
How do limpets stick to rocks? ›Limpets have adapted to survive the intertidal zones of the rocky shore. Their strong foot muscle attaches the shell to rocks, preventing desiccation at low tide, and anchors the animal in rough seas.