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INTERTIDAL ZONE; Random sampling hard (rocky, coral or shingle) and soft (sand or mud) shores

 

Equipment list

Long tape measure or rope

GPS receiver

Recording table and pencil

1sq.m or 0.25sq.m quadrat

Plastic pipe for taking mud cores

Wire mesh sieve

Trowel

Bucket

Ruler

Hand lens or camera with magnifier app.

 

 

For investigating and comparing biodiversity or to study species adaptations.

Soft shore. This may be mud or sand.

 

  1. Lay the knotted rope or tape measure parallel to the water line about 1m up. This is your transect line.

  2. Generate 2 random numbers. The first, between 0 and 30 is how far along the transect line you go, the second, between 0 and 10 is how many meters away from the transect, at right angles, you go up the shore.

  3. Place the quadrat and look for evidence of what organisms are present in the square. You may find holes, (burrow openings), worm deposits (faecal casts).Count and record these on your sheet.

  4.  Take  4  core  samples.    This will give you a measure of what lives just under the sediment.  Starting in one corner,  push in the core to a depth of 10cm and use your trowel to dig it out.  Tip it into the sieve and pour water through it to wash off the sand and mud. Count and record the different species.  Repeat in the other 3 corners of the square.

  5. Record  your  survey  information.    Record the location of the site. This can be done using a GPS function on your phone, or the name of the beach or a local landmark.  Write a brief description of the site including possible influences on the plants and animals living there.  Record the shore type, and describe the sediment found in your square.

Hard shore. This may be rock, boulders or dead coral.

 

  1. Carry out steps and 2 as for soft shore.

  2. Start in one corner of your square and record the abundance (“how many” or “how much”) of plants and animals that you can see without moving any rocks or seaweed. The simplest way to measure abundance is to count the number of animals inside your square. Some small animals like barnacles can be found in very large numbers and it may not be possible to count all of these animals accurately inside your square.  You can do a rough count in a small part of your square and scale this up.    Measure the abundance of seaweeds using percentage cover.  This is the percentage of the surface inside the square that is covered by the seaweed when looking down.  Don’t forget to look on and under seaweeds, inside rocky crevices and beneath small boulders and cobbles for hidden animals.  If you turn any rocks over remember to return them gently to their original position. Do  not  lift  rocks  or  boulders  that  are  larger  than  your  head.

  3. If you find a species that is not on the list, write its name or a description of it in empty boxes in the species list. If you can, take a photo of it with a ruler in the shot to indicate its size. Write a brief description of where it was found and what is was doing: this information can help identify it later.

  4.   Record  your  survey  information.    Record the location of the site. This can be done using a GPS function on your phone, a grid reference from a map, or even just the name of the beach or a local landmark.  Write a brief description of the site including possible influences on the plants and animals living there.  Record the main type of surface in your square by circling one of the shore types.  Rock is a continuous hard surface or large, stationary boulders .  A soft shore is a mainly sand or mud.  A mixed shore has a mixture of different sized rocks that can be moved easily such as cobbles (fist-sized), pebbles (coin-sized) and gravel (pea-sized), as well as some sand or mud  

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hardshore.jpg
softshore.jpg
Hard and soft shores

Reflection

  • Did you find a significant difference in biodiversity between the two shores?

  • Which had a greater variety of plant and animal life? Can you suggest reasons for this?

  • On which shore are the organisms more specialized?

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