High Energy Shoreline Habitat

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High Energy Shoreline Habitat

Lab report by Robin Batcheller

Introduction:
Sandy beaches are an example of a high-energy shoreline habitat. A high-energy habitat creates environments of lots of wave action. On wave-exposed sandy beaches, waves continually scour the surface of the beach thereby preventing the establishment of a stable benthic environment (Bertness 1999). The only organisms that can live in this environment are those that can tolerate and deal with such conditions. In addition to the high amount of wave action, there are large fluctuation is the temperature. In the daytime it can be very warm and when the tide comes in, the temperature can become quite cold. There is also very little freshwater available and there is no firm substrate for the organisms to attach themselves to. This makes finding a home at the Sandy Beach somewhat of a challenge. The slope at the beach is also a very important factor to consider. The slope at the Sandy Beach is very gradual. This means that the wave action is not as severe to the organisms. The Sandy Beach is divided into four different sections: the upper beach, the strandline, the intertidal zone and the lower beach. At each of these sections there are specific species that are found at those specific locations. The Sandy Beach is filled with a variety of disadvantages as well as the possibilities for some very interesting creatures.

The Rocky Intertidal zone is also a part of the high-energy shoreline habitat. At high tide, there is high wave energy. The water hits the rocks at full force for the slope is higher whereas the slope at the Sandy Beach is more gradual. The rocky intertidal organisms can be subjected to severe wave stresses that can separate them from their substrate, limiting their mobility and influences their size and morphology (Bertness 1999). At low tide, there are extreme temperatures and the danger of desiccation is great. The Rocky Intertidal zone is divided into several different zones such as the upper intertidal zone, middle intertidal zone, and the lower intertidal zone. Each of these zones are subdivided even further, and each of these subdivisions are dominated by one specific species. While the life in the Rocky Intertidal zone can be rough, it does not mean that there is a lack of species at this habitat. The Rocky intertidal habitats are home to many to many sessile and slow-moving invertebrates, as well as algae capable of dealing with widely fluctuating physical conditions (Bertness 1999).

The purpose of the study was to examine the Sandy Beach environments and to look at the Rocky Intertidal zone. At the beach, the goal was to identify as many different species as possible and at the Rocky Intertidal zone the objective was to study the different zones the rocky intertidal setting has. At each of the different zones, the discovery of the dominant species was also desired.

Methods and Materials:
On May 23, 2002, the class went to two different locations to study marine life and their habitats. One was the Sandy Beach and the other was the Rocky Intertidal Zone. For the experiment, marine ecology books, including the field guide Martinez, 1999 were used for the identification of the many species located at the Sandy Beach area. The class broke up into several different groups, trying to identify as many organisms as possible. Walking up along the beach area and then up along the rocky area, a species list was then created. At the Rocky Intertidal zone, species were also identified but this time they were also placed into what zone they belonged to. For instance, the Rocky intertidal zone used in the experiment was composed into the upper intertidal zone and the middle intertidal zone. In the upper intertidal zone, there was the black zone, and in the middle intertidal zone, there was the barnacle zone, fucus zone, and finally the mussel zone. While some of the students participated in the activity of species identification, others measured the width of each of the four zones with measuring tape five different times so that a mean could be calculated.

Results:
The data collected showed a variety of different organisms located at both the Rocky Intertidal zone and at the Sandy Beach. The organisms found at the Sandy Beach, for example, all show to be organisms found in or by rocky areas (Table 1). There were very few organisms found on the actual sandy beach area. Table 2 also shows the different species found at the Rocky Intertidal zone. Most of the organisms found were located in either the Fucus zone or the Mussel zone. The mean widths of each of the four different zones were also found. The mean width of the Black zone for instance was 72 cm, 169 cm for the Barnacle zone, 586 cm for the Fucus zone and finally 620.4 cm for the Mussel zone (Table 1). The standard deviation was also calculated to determine whether not the results were as accurate as possible or if the data was all over the place. It was found that the Black zone had the smallest deviation number followed by the Barnacle zone, the Mussel zone and then the Fucus zone (Table 3).

Discussion:
When the data from the field species lists and the zone widths were collected, it was concluded that environmental conditions either allowed the organisms to thrive in the area they lived in or prevented them from inhabiting the desired area. For example, it was found that the organisms located at Sandy Beach were those of a rocky habitat. There was very little life in the actual beach area and most of the marine life was found by the rocks surrounding the beach. In the Rocky Intertidal zone, results showed the zones where the organisms were the most comfortable and the areas where they could find space. The main factors determining where which areas live where depends on where there is open space available and where the organisms do not have compete. One would imagine for example that the fucus zone would be inhabited by the seaweeds and algae yet it was found that in fact other organisms inhabited this area including green crabs, forbes’ sea stars, baltic isopod, and the atlantic dog welk.

The next goal is to determine why the data showed the result they did. In order to determine this information, it is important to reconsider the setup of both the Sandy Beach and the Rocky Intertidal zone

The Sandy Beach is an area of very little life. There a variety a conditions that prevents such marine organisms from making a home in this area and move onto areas where they can attach themselves. For instance, where information was gathered, in the upper beach area, the temperature was very hot and dry and there was very little protection from the wind. There is also very little freshwater available for the organisms to take advantage of. Because there is a lack of a firm foundation, the organisms must either bury themselves or move on to the nearby rocky areas in order to make their homes. The only organisms located on the actual beach area are those animals that can stand such conditions. These organisms include ghost crabs, beach hoppers or beach fleas and sand fleas. There is very little food available for these organisms to eat and therefore those that do live on the beach area must be scavengers to obtain the food necessary for survival. The strand line at the beach also had some material. Most of the matter there, however, is dead stuff including seaweed, sea grasses and other organic material. Therefore, it was no surprise that most of the organisms found on the field trip were those found on the rocks rather than on the actual beach area.

Another aspect of the field trip was to look at the type of beach the Sandy Beach was. Most of beaches on the east cost of the United States are dominated by quartz in the sand. The Sandy Beach, however, is the only beach on the east coast having sand made up of 75% of calcium carbonate. In normal cold water conditions, the calcium carbonate becomes dissolved into solution and there is less calcium carbonate being produced. However, in the Sandy Beach, even though the calcium carbonate is being dissolved into solution is there is a much higher calcium carbonate production rate. This is quite unusual for colder area such as Maine.

The Rocky Intertidal zone is another interesting habitat. At high tides there is the danger of high-energy wave action. This is because the slopes of the Rocky Intertidal zones are very steep which means when the wave hit the rocks, they hit at full force. This means that the organisms must glue themselves to the firm substrate or find an area to hide themselves. At low tide, there is there is the chance of desiccation and extreme temperatures. The Rocky Intertidal Zone therefore must find an area where they can attach themselves to and this inevitably leads to competition and predation. For instance, in the Black Zone, located in the upper intertidal zone, most of the organisms found in this region were the lichens and the algae. These are the primary producers for this habitat. It was interesting to see that there was no lichens found at the upper intertidal zone. The other zone in the upper intertidal zone dominated by Littorina was not calculated for the tide was out and the ability to locate these organisms was not possible. The organisms’ main limiting factor is this zone desiccation. If there is not enough water available for these organisms, there is the danger of drying out. In the Barnacle zone, the upper limit for these organisms is desiccation and the lower limit is competition. For the Fucus zone, the upper limit is desiccation and the lower limit is competition. Finally, for the mussel zone, the upper limit is competition and the lower limit is predation. All of these organisms need to find a place attach themselves to. They all need to find a place to hold onto otherwise they would all wash away and this means there is fierce competition for space. The results of the experiment showed this finding. For instance, in the mussel zone, focus zone and barnacle zone, the organisms found were all over the place. The reason for this is because the main thing for these organisms is space. They go wherever there is an open place presented to them.

Therefore, it can be concluded that environmental conditions have a great affect on where many marine organisms live in both the Sandy Beach and the Rocky Intertidal zone. In the Sandy Beach for instance, temperature, water availability, wave action and the lack on a firm substrate all determine where an organisms will live whereas competition/space availability in the Rocky Intertidal zone will determine where an organism will live. All of these factors are the result of the tidal waves. The high energy waves pound on the shore and the rocks creating the different zones and the unfavorable conditions at the beach for the animals to live in.

Literature cited:
Bertness, Mark D. The Ecology of Atlantic Shorelines. Sinauer Associates Inc. Massachusetts. 1999.