Aim:
Background:
Splash zone
This is the most difficult zone of the four sones for inter tidal organisms. The immersion time is 0% but the top of the zone is not easily identified as it is dependent on the size of the waves and thus their splash size. As we carried out our experiment on a sheltered shore we would not expect there to be a large splash zone. There is high salinity in this areas and extremes of temperature. As it is right next to the shore there may be strong winds which would lead it to be difficult for large plant organisms to survive. There may be very little available water and sea bird droppings cause high phosphate and nitrate levels which may either help or hinder a particular organisms growth.
The organisms often found on the splash zone is a large abundance of lichens as they are terrestrial but tolerant of salt. The colonise bare rock and are able to turn this, over time through the action of acids, into bare soil/hummus causing moses and a few flowering plants to be able to colonise the area. The plants have to also be tolerant of high salt content, an example would include thrift.
There is no macro-algae in this zone as they need a good water supply so they can carry out gas exchange and float to increase their photosynthetic capabilities. They also use the water for structure and support.
There are often very few animals found here but interestingly a marine snail has several adaptations that allow it to survive this far up the shore. It avoids dehydrtion by being encased in a waterproof shell that acts as a trap door, it respires in air and is able to feed on lichens where there is a largely reduced competition level that lower down on the shore. It also has a sticky muccus that allows it to stick to rocks with ease.
Upper shore:
This is still a difficult environment for inter tidal organisms. The immersion times are 1% at the top of the zone and 20% at the bottom. The issues faced by organisms that live there is desiccation, extremes of temperature, strong winds and lots of sunlight yet slow growth due to the shortened time to obtain nutrients.
Lichens are able to survive in this zone as different species can survive in different conditions. this often results in a different colour band in this area than in the splash zone. Channelled wrack [Pelvetia canaliculata] and twisted wrack [Fucus spirals] can survive here out of the brown algae and the red algae [Catenella caespitosa] may also be found. Sea weeds are able to tolerate the water loss as they can rehydrate quickly.
Marine animals that are able to cope with he challenging environment as mentioned above are able to survive. They are normally shelled animals like the rough periwinkle which grazes on the algae and lichens but barnacles can also inhabit this area. Most of the animalsahve shell but the exception to this rule is the Beadlet Anemone [Actina equina] which is a soft bodied organism that survives due to a sticky muccus and retractible tentacles.
Middle shore
This zone is good for inter tidal organisms. The immersion times are at the top of the zone 20% and at the bottom of the zone just below 80%. As we move down this zone the number and variety of organisms increases so we often find that the difference between the number and type of organisms at the top and bottom of this zone can differ drastically. In the middle shore, unlike the lower shore we begin to see the issue of desiccation which is the extreme drying of organisms when they are not submerged under the water. This also leads to variable temperatures as the organisms can experience long periods of immersion in cold water and then long periods pf being exposed to sunlight causing their increase in temperature. There is also a lower light level than that of the upper shore.
Typical species found on the middle shore is a large abundance of algaes like the bladder wrack [Fucus vesiculosus] which falls into a heap as the tide goes out , egg wrack and red seaweed pepper pulse [Osmundea pinnatifida] which is able to regrow pigments and thus overcome the major problem red algae have when exposed to sunlight.
There is a larger number of organisms on the middle shore than on the upper shore as increased immersion times for a greater % of the year provide more foo and feeding time for filter feeders like barnacles. This also leads to a larger quantity of herbivores than on the upper shore and in turn leads to an increased number of carnivores. Shelled species thrive like that of periwinkles snd dog whelk feed on the barnacles. As it is more sheltered than the upper shore you may also find crabs able to survive there.
Lower shore
This is theoretically the best zone for inter-tidal organisms. On a typical shore this zone will support most species. The lower shore is the area where at the top of the zone the immersion level times is around 80% and at the bottom of the zone the immersion time is around 99%. The general ecosystem of the lower shore is that there are no species of lichen but there is a large abundance of different types of sea weeds. There is brown algae, a typical example being the serrated wrack [Fucus serratus] and the Sugar Kelp [Saccharina latissima]There may also be a few types of both red and green algae as conditions improve to the top end of the lower shore zone. There may also be an increased number of animals in this zone one reason for this may be the greater productivity of algae leading to more herbivores being able to survive in this area, an example being the blue-rayed limpets.
Method:
We carried out our experiment on jetty beach which is a sheltered rocky shore.
- To understand how to use a quadrant to estimate density and percentage cover
Background:
Splash zone
This is the most difficult zone of the four sones for inter tidal organisms. The immersion time is 0% but the top of the zone is not easily identified as it is dependent on the size of the waves and thus their splash size. As we carried out our experiment on a sheltered shore we would not expect there to be a large splash zone. There is high salinity in this areas and extremes of temperature. As it is right next to the shore there may be strong winds which would lead it to be difficult for large plant organisms to survive. There may be very little available water and sea bird droppings cause high phosphate and nitrate levels which may either help or hinder a particular organisms growth.
The organisms often found on the splash zone is a large abundance of lichens as they are terrestrial but tolerant of salt. The colonise bare rock and are able to turn this, over time through the action of acids, into bare soil/hummus causing moses and a few flowering plants to be able to colonise the area. The plants have to also be tolerant of high salt content, an example would include thrift.
There is no macro-algae in this zone as they need a good water supply so they can carry out gas exchange and float to increase their photosynthetic capabilities. They also use the water for structure and support.
There are often very few animals found here but interestingly a marine snail has several adaptations that allow it to survive this far up the shore. It avoids dehydrtion by being encased in a waterproof shell that acts as a trap door, it respires in air and is able to feed on lichens where there is a largely reduced competition level that lower down on the shore. It also has a sticky muccus that allows it to stick to rocks with ease.
Upper shore:
This is still a difficult environment for inter tidal organisms. The immersion times are 1% at the top of the zone and 20% at the bottom. The issues faced by organisms that live there is desiccation, extremes of temperature, strong winds and lots of sunlight yet slow growth due to the shortened time to obtain nutrients.
Lichens are able to survive in this zone as different species can survive in different conditions. this often results in a different colour band in this area than in the splash zone. Channelled wrack [Pelvetia canaliculata] and twisted wrack [Fucus spirals] can survive here out of the brown algae and the red algae [Catenella caespitosa] may also be found. Sea weeds are able to tolerate the water loss as they can rehydrate quickly.
Marine animals that are able to cope with he challenging environment as mentioned above are able to survive. They are normally shelled animals like the rough periwinkle which grazes on the algae and lichens but barnacles can also inhabit this area. Most of the animalsahve shell but the exception to this rule is the Beadlet Anemone [Actina equina] which is a soft bodied organism that survives due to a sticky muccus and retractible tentacles.
Middle shore
This zone is good for inter tidal organisms. The immersion times are at the top of the zone 20% and at the bottom of the zone just below 80%. As we move down this zone the number and variety of organisms increases so we often find that the difference between the number and type of organisms at the top and bottom of this zone can differ drastically. In the middle shore, unlike the lower shore we begin to see the issue of desiccation which is the extreme drying of organisms when they are not submerged under the water. This also leads to variable temperatures as the organisms can experience long periods of immersion in cold water and then long periods pf being exposed to sunlight causing their increase in temperature. There is also a lower light level than that of the upper shore.
Typical species found on the middle shore is a large abundance of algaes like the bladder wrack [Fucus vesiculosus] which falls into a heap as the tide goes out , egg wrack and red seaweed pepper pulse [Osmundea pinnatifida] which is able to regrow pigments and thus overcome the major problem red algae have when exposed to sunlight.
There is a larger number of organisms on the middle shore than on the upper shore as increased immersion times for a greater % of the year provide more foo and feeding time for filter feeders like barnacles. This also leads to a larger quantity of herbivores than on the upper shore and in turn leads to an increased number of carnivores. Shelled species thrive like that of periwinkles snd dog whelk feed on the barnacles. As it is more sheltered than the upper shore you may also find crabs able to survive there.
Lower shore
This is theoretically the best zone for inter-tidal organisms. On a typical shore this zone will support most species. The lower shore is the area where at the top of the zone the immersion level times is around 80% and at the bottom of the zone the immersion time is around 99%. The general ecosystem of the lower shore is that there are no species of lichen but there is a large abundance of different types of sea weeds. There is brown algae, a typical example being the serrated wrack [Fucus serratus] and the Sugar Kelp [Saccharina latissima]There may also be a few types of both red and green algae as conditions improve to the top end of the lower shore zone. There may also be an increased number of animals in this zone one reason for this may be the greater productivity of algae leading to more herbivores being able to survive in this area, an example being the blue-rayed limpets.
Method:
We carried out our experiment on jetty beach which is a sheltered rocky shore.
- With the help and assistance of our specialist supervisor John he showed us the general zones and areas of the rocky shore. At each zone we randomly placed our quadrat down in an area using a random number generator on our calculator to find whereabouts horizontally on the shore we should put our quadrant.
- When we got to our quadrant we obtained a rough estimate of the quantity of animals and plants in that area. Using the ACFOR scale we rated the percentage cover of that species in terms of the whole area of the quadrant and then gave it a letter and noted it down on our species sheets.
- The ACFOR sampling method is a simple but subjective method of sampling but it is easy to use on fieldwork. A= abundant C= common F= frequent O= occasional R= rare. We were given percentage numbers that would correlate to each of these letters that further held us in determining the percentage cover.
- Once we had judged this and noted it we repeated this step at all four zones of the sheltered beach.
- When we got back to the classroom we looked at our results and saw of they supported what we had learnt about the donation of species on shores.
These are the table of rough results we recorded on during our field work study. The column 1, 2, 3 and 4 represents the lower shore, middle shower, upper shore and splash zone respectively for both sheets.
As can be seen on the pink sheet which was our record sheet for the animal species in the area there was no recorded animals in our quadrats for either the upper shore or splash zone. This supports what we were taught in the lesson and what i have explained above about the difficult environment the upper shore and splash zone are for organisms to inhabit.
However, there was a larger number of animals on the lower shore and middle shore but because of the size of these organisms we could not give them a large percentage cover even though there were intact a large quantity of the animals.
As can be seen on the green sheet there were no lichens present on the lower shore and middle shore but a large abundance of them on the upper shore and splash zone. There was also a large abundance of different algae/ sea weeds on the lower shore and middle shore but only one type was found on the upper shore ( creeping chain weed) and none on the splash zone. This further supports and correlates to what we learnt and i have explained above about the distribution of lichens and sea weeds in each zone. They are both dependent on different factors an have adapted to survive in particular conditions. This also further brings to the fore that rocky shores have vast changes in the environment as this is highlighted by the huge change in different species as you move from each zone.
As can be seen on the pink sheet which was our record sheet for the animal species in the area there was no recorded animals in our quadrats for either the upper shore or splash zone. This supports what we were taught in the lesson and what i have explained above about the difficult environment the upper shore and splash zone are for organisms to inhabit.
However, there was a larger number of animals on the lower shore and middle shore but because of the size of these organisms we could not give them a large percentage cover even though there were intact a large quantity of the animals.
As can be seen on the green sheet there were no lichens present on the lower shore and middle shore but a large abundance of them on the upper shore and splash zone. There was also a large abundance of different algae/ sea weeds on the lower shore and middle shore but only one type was found on the upper shore ( creeping chain weed) and none on the splash zone. This further supports and correlates to what we learnt and i have explained above about the distribution of lichens and sea weeds in each zone. They are both dependent on different factors an have adapted to survive in particular conditions. This also further brings to the fore that rocky shores have vast changes in the environment as this is highlighted by the huge change in different species as you move from each zone.
Limitations
- The ACFOR method has huge limitations.
- The judgement of percentage cover is subjective which makes our letters less reliable as what may be 'abundant' for one individual is 'common' for someone else. This is why I feel it is more important to look also at the change in different types of species rather than just their abundance.
- We were given a percentage for each of the ACFOR letters to try and help in our decision making. However, as we were judging on percentage cover this didn't take into account the size of the species. There were income cases many flat periwinkles but due to their size we could only give them a 'rare' even though there may have been a larger quantity of them compared to some of the larger animals we were measuring.
- Species can also be easily rated on how obvious they are rather than how abundant they are.
- The Quadrats.
- There was a limitation to the area you could measure so there may have been certain mor abundant species in the zone that you were unable to identify as they weren't found in the quadrat
- The randomness of the sampling we tried to control but you may be more inclined to place the quadrant in an interesting area like a rockpool which would have affected the number of species and type of species found.
- Decisions also had to be made about whether we should include or exclude organisms partly covered by the quadrat.
- As we were measuring moving animals (particularly in the lower shore, like crabs) it was often hard to get an idea of how many of the animals we should include as they often escaped out of the quadrat.
- The 2D characteristic of the quadrat made it hard to judge whether we should include certain species when it was placed against the rocks on the upper shore and splash zone as these rocs were steep with many crevices.
- In the lower shore due to the large volume of sea weed it was often hard to identify all the species in the quadrat as smaller organisms like crabs could hide from our view.
- We did not have time to repeat our experiement which would have given us more data and thus a wider and more reliable picture of the real type of species and quantity comparison.
- The issue of microhabitats in each zone may have also been an issue. There may have been a large number of different species in only a certain area of the zone where our quadrat just happened to be. An example of this would be a rock pool in the upper shore that may show a larger range of animals and plants than is really a fair representation of that zone. This limitation could have been overcome by doing repeats of our results