セクションアウトライン

    • In the rocky intertidal zone, sessile organisms such as seaweed exhibit a zonal distribution with different habitat heights depending on the species. In this practice, the belt transect method is used to investigate its vertical distribution.

       

      Tools:

      Rope, quadrat (20cm x 20cm), angle scale, drawing board, underwater notebook, graph paper, pencil, folding scale, silicon tube, plastic bag, box glasses

       

      Method:

      （１）　A survey line is set by laying a rope at a predetermined survey location (where a zonal distribution can be seen, including from the top of the vertical distribution to the lower part of the intertidal zone).

      （２）　Place the quadrat along the line, apply the slant rule parallel to the line and record the angle.

      Figure 1

      （３）　Record the types and coverage of creatures within the quadrat. In addition to algae, sessile animals and creeping animals with a narrow range of movement are also recorded. Coverage is the percentage of the area covered by the organism within the quadrat. The bare surface percentage is also measured and recorded. If it overlaps with other creatures, the total coverage of the species that appeared there may exceed 100%.

      Give a value every 10% on the spot. If it is less than 5%, it will be +. Coverage may later be indicated in six ranks as follows:

      　＋（＋）；　1（5-20％）；　2（20-40％）；　3（40-60％）；　4（60-80％）；　5（80-100％）。

      　If it is difficult to identify the species, bring back the specimen and examine it, or classify it as "Sargassum juvenile" or "Filamentous microalgae". Decide in advance how to classify. Write the quadrat number on the plastic bag and put the creature to bring back there.

      　It is useful for the scribe to record an approximate cross-sectional profile of the entire survey site for later reconstruction of the profile. It is also a good idea to record the position of the sea surface at the time of the lowest tide in the survey site profile.

      （４）　Place the quadrat at an adjacent location along the line and make a similar score. This is repeated until the end of the survey line is reached.

      （５）　Check the time of low tide and tide level on the day of the survey, and record the actual sea level at that time on the line during the survey.


    • Fig. Investigation by belt transect method and zonal distribution of seaweed

    • Summary of results and presentation:

      (1)      The results of the vertical distribution survey will be summarized as a graph for each group, and each group will make a presentation on what can be said from the survey results using the graph.

      (2)       Based on the angles recorded in method (2), create a cross-sectional schematic diagram of the survey line (transect) using graph paper.

      (3)       The results of the survey (distribution of each organism) are shown in diagrams and graphs on the schematic cross-sectional view.

      (4)       Infer the environmental factors and the physiological characteristics of those organisms, and consider the results (from the survey results, what kind of tendency is there in the emergence of species, what factors are responsible for it, etc.). In doing so, it is advisable to pay attention to the lifestyle (body shape and life span type) of the emerging species.


      (5)       Each group presents an overview and discussion of the survey results while showing the created chart.