Columnar Barnacles and Oyster Borer

My investigation focus is to find the distribution pattern of Oyster Borer (Haustrum Scobina) and Columnar Barnacles (Chamaesipho Columna) and to show how the two species relate using quantitative data.

Description of Pattern

Barnacles

My data showed barnacles were often grouped together showing clumped distribution pattern. This was not necessarily because of resources but the clumping of barnacles is needed for reproduction as barnacles cannot move and need to reproduce with another barnacle.

My data also showed barnacles were most common in the intertidal zone (70cm-105cm above sea level) with an average of 1077 (in 15 quadrats) in the intertidal zone compared with 3.33 and 46.6 in the low tide zone and high tide zone respectively. Barnacles zonation is in the intertidal zone because the amount of barnacle predators increases with more submergence time.

Barnacle zonation was also extremely concentrated as shown by the sum of the number of barnacles. There were 16,000 barnacles in the intertidal zone compared with 50 in low tide zone and 700 in high tide zone. This shows that the biological markup of barnacles does not suit the environmental factors in the low tide zone and high tide zone and that once given the right environment, barnacles survive in large numbers.

Columnar Barnacles	Low Tide	Intertidal Zone	High Tide
Average	3.333333333	1076.8	46.66666667
Sum	50	16152	700

Photo from data collection day.

Oyster Borer

My data showed oyster borer were found in all three zones but were most common in the intertidal zone. This can be seen in the data by an average of 3.8 oyster borer in the intertidal zone compared with 0.67 and 1.2 oyster borer in the low and high tide zones respectively.

Oyster Borers had a clumped distribution in our research and data. We tended to find oyster borers together and this was because of resources such as barnacles which they eat.

Oyster Borer	Low Tide	Intertidal Zone	High Tide
Average	0.6666666667	3.8	1.2
Sum	10	57	18

Environmental Factor

An abiotic environmental factor which affects both oyster borers and barnacles is the tide level and vertical height which both determine how much time they both spend submerged underwater. This factor itself is important because it also controls other environmental factors like temperature (sea is colder than land) and expose to sun.

Barnacles

Barnacles are filter feeders and eat plankton, algae and bacteria that is floating in the water. Due to the nature of their food, they can only get access to the food while they are in the water as they use their tentacles so they need to be submerged underwater at some points during the day. They also need to get access to water so they do not become desiccated.

Because they are not covered by water all the time, they seal water inside them to last until the tide comes back out. (Explain how tide affects a barnacles and oyster borer)

Oyster Borer

Oyster Borer also need water to survive by preventing desiccation. For this reason they should be covered by water twice a day and the length of time covered it determined by them being in the intertidal zone. Oyster Borer also feed underwater so they need to be exposed to water to water long enough to eat the barnacles and to move to them.

If there was not enough submergence time, oyster borer would die because they wouldn’t be able to eat the barnacles.

If hypothetically the intertidal zone had a longer submergence time, barnacles would be eaten out by other predators and no food would be left for Oyster Borer and so they would die out. Oyster Borer cannot go too far down the zones because the further they go down, the less food source even though they can spend more time eating. These are the reasons why Oyster Borer stay in the intertidal zone.

Ecological Niche

Barnacles

Barnacles live on rocks in the intertidal zone avoiding predators who need a large submergence time while filter feeding on plankton, algae and bacteria. Oyster Borer are its main predator.

Adaptations

Barnacles

Barnacles have impervious shells that can resist predators and can take the impact of waves. The shape of barnacles is hydrodynamic which means waves can easily wave over it causing no damage to the barnacles. This is a structural adaptation. This allows barnacles to be on rocks that are impacted by waves a lot and some of these high rocks could be considered the intertidal zone where we find these barnacles. Because barnacles have this adaptation, they can live on exposed rocks when some other species cannot.

Barnacles have a high temperature tolerance which is important because in rock pools the temperature can fluctuate a lot.

Barnacles have a few adaptations which allow them to be in the intertidal zone as opposed the low tide zone where they are survive less. Firstly, barnacles have a valve which opens and closes to keep water in and process food while also preventing desiccation. While underwater, barnacles open their valves and extend their cirri (tongue like) to gather plankton and algae from the water. Once the tide starts going out, barnicles close their valves to process the food they have gathered and they process this food while outside the water. This valve is made up of multiple plates which successfully seal the water but also keep predators out. This valve allows barnacles to stay out of the water longer than other animals that cannot seal water inside themselves. Because of this physiological/behavioural adaptation, we find barnacles more commonly further up in the intertidal zone.

Barnacles are also able to stick themselves to rocks very solidly and this is a behavioural adaptation by which they release a cement to glue themselves down.

A physiological adaptation is enzymes the barnacles release to break down plankton, algae and bacteria.

Ecological Niche

Oyster Borer

Oyster Borer feed on barnacles in the intertidal zone avoiding competition because of their adaptations which resist desiccation and allow them to stay in the intertidal zone. Oyster Borers are eaten by whelks.

Adaptations

Oyster Borer

Oyster Borer had a tooth ribbon (radula) which allow them to drill into mussels and barnacles and eat the organisms from the inside out. This is a structural adaptation allows Oyster Borer to drill into mussels in as little at 45 minutes.

When feeding on barnacles, Oyster Borer insert their foot into the barnacle before consuming the flesh, this is a structural adaptation.

The shell of a Oyster Borer helps to camouflage it into the rocks around and also provides protection from the waves and potential predators. This is a structural adaptation.

Oyster Borers use a mucous near the entrance to the shell to stop desiccation as they live in the intertidal zone. This structural adaptation allows them to stay out of water from longer than therefore allows them to live further up on the rocky shore.

Interrelationship

The interrelationship between these two animals is predation. Oyster Borer eat barnacles on the rocky shore and so we would expect to find them occupying the same areas. As barnacles mainly occupy the intertidal zone, this is where we would expect to find the most Oyster Borer.

Barnacles and Oyster Borer

Discussion

The tide level/vertical height is an environmental factor that with a barnacles adaptation, can explain the pattern. The tide level affects submergence time and the more time spent submerged mean more access to water but it also means more predators for Barnacles. For this reason they survive more in the intertidal zone but they can only do this because of an adaptation that stops water desiccation. The valve of the barnacle closes up when the tide goes in so that the barnacle has water even when the tide is in. This valve is comprised of multiple plates that move to close up when there is low tide. The barnacle also has an adaptation which allows it to process its food outside of the water. These two adaptations mean that barnacles have to spend less time in the water each day to survive and can therefore live further up the rocky shore compared with other organisms. This suits barnacles because the intertidal zone, has less predators as many of their predator need to eat them underwater for extended periods of time.

Oyster Borer eat the barnacles that are living in the intertidal zone. This is why Oyster Borer stay in the intertidal zone, because of their food source. This is relevant because if barnacles did not have these adaptations they would live further down the shore and spend more time submerged underwater. This would mean other predators would eat the barnacles and so there would not be much left for Oyster Borer. Oyster Borer would then not fulfill their ecological niche and they would die out.

My data supports this theory that there is a relationship between Oyster Borer and barnicles. In the low tide zone we only found an average (from 15 quadrats) of 3.33 barnacles and 0.67 oyster borer. In the intertidal zone we found an average of 1076.8 barnacles and a higher 3.8 oyster borer. In the high tide zone, we only found 46.67 barnacles average and 1.2 oyster borer average.

This clearly support the relationship link as where there is a large amount of barnacles, the number of oyster borers is also larger. We could also see this when taking our data because many of the barnacles were dead and oyster borers were around.

Average Population in Quadrat	Low Tide	Intertidal Zone	High Tide
Barnacles	3.333333333	1076.8	46.66666667
Oyster Borer	0.6666666667	3.8	1.2

Total Population in Quadrat	Low Tide	Intertidal Zone	High Tide
Barnacles	50	16152	700
Oyster Borer	10	57	18

Bibliography

Between the Tides

http://www.tandfonline.com/doi/pdf/10.1080/00288330.1975.9515574

http://www.seafriends.org.nz/enviro/habitat/shore1.htm

http://bio.research.ucsc.edu/people/carr/Raimondi%20Reprints/Barnacle%20chapter%20proofs.pdf

http://www.nhm.ac.uk/resources-rx/files/10feat_secret_life_of_barnacles-3061.pdf

http://www.seafriends.org.nz/enviro/habitat/rsmoll.htm

http://www.mesa.edu.au/atoz/Mulberry_Oyster_Borer.asp