Rock Pooling
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Rock Pooling When you next go to the beach why not have a look in the rock pools which are exposed at low tide? These pools are home to lots of plants and animals which need to stay underwater when the tide goes out, so they take shelter here. Print this guide out and take it along to help you. When you next go to the beach have a look in the rock pools which are exposed at low tide. These pools are home to a lot of plants and animals which need to stay underwater when the tide goes out, so they shelter in the pools. The pools may look tranquil compared to the sea but life here is very harsh; the water can get very warm in the sun and can even dry up if it gets too hot and when it rains the water becomes less salty and more like a pond than the sea. So all the plants and animals you see have had to adapt in special ways to live there. Here are some pictures of the plants and animals you are likely to see in this area but you will probably see many more once you start looking…. This picture shows sea anemones (pronounced an-em-on-ees) in a rock pool at Hackley Bay. They are animals which attach to the rocks in sheltered parts such as rock pools and under big rocks to protect them from the waves. Anemones feed by drawing food in through their mouths which is in the centre amongst the tentacles-they only have one opening though as they are very basic animals so they go to the toilet out of the same hole as what they use to eat! Beware, the tentacles you see on a anemone are stinging-do not touch! Anemones come in many different colours but usually you will see red ones. They only have their stinging tentacles out when they are covered with water so at low tide they will look like the picture below. This is what anemones look like at low tide -little blobs of jelly. They close up like this so they don't dry up when they are not under water. The picture below shows a 'home scar' of a limpet. The scars are where the limpets go back to each night after they have finished feeding. The limpets make these scars by using acid from their bodies to dissolve a little hole in the rock which is exactly the right size for their shell, this makes it easier for them to hold on in big waves and stop the water coming into their shell. This is a typical rock pool, there are lots of empty shells in the bottom but some of these will be used by other animals as a new home, such as the hermit crab. There is also some red seaweed but look carefully as it comes in all shapes, sizes and colours-you will see seaweeds in red, brown and green. Zonation • At the top of the beach is the splash zone – splashed occasionally by the waves but never submerged. Very little lives here – it is a sort of limbo zone where terrestrial plants can’t survive because they can’t tolerate the salt spray, but marine life can’t survive because it’s too dry. Lichens live here. • On the upper shore it is more dry than it is wet but it does get submerged during the peak of the high tide. Things that can survive long periods out of the water survive here, such as periwinkles and dog whelks. • The middle shore is wet for longer period but is still completely exposed to the air at times. Here you will find barnacles, limpets and wracks. • The lower shore is below the mean low water mark so is only occasionally exposed during low spring tides. Here you will find the kelps. Effects of light • Seawater absorbs different wavelengths (or colours) at different rates. Red is the first to be absorbed. • You will find green seaweeds on the upper shore for the same reason you find green plants on land – they do not use the green wavelengths for photosynthesis so they reflect it and appear green. • You will find brown seaweeds in the middle and lower shore as less red light is available. • In rock pools and below the low water mark where the seaweeds are permanently covered in water you will find the reds. There is no red light for them to use so they reflect it. • Don’t get too bogged down in this – it can get complicated if you think about it too much! Holding on Plants and animals on the shore are pounded by waves and pulled by currents so have employed various methods of holding on. • Glue/cement-Barnacles permanently fix themselves to the rocks and never move once they are settled. • Suck hard! Some animals suck onto the rocks with a big muscular ‘foot’ – periwinkles, dogwhelks, the snail type things. • Tying up- Mussels exude sticky threads, which they hope will become entangled on seaweed or other life, and hold them on. • Hide-Many animals would rather just hide than expose themselves to the hazards of waves – look under rocks and in crevices and you will find the more vulnerable, less protected animals- anemones, worms, shrimps, etc. • Holdfasts-Terrestrial plants get water from the soil through their roots but seaweeds live in water so don’t need roots for this purpose. They do, however, need to hold on so have ‘holdfasts’ for this purpose and these can sometimes look like roots. GOING ROCK POOLING WHERE? -There are many good places to go rock pooling south of Aberdeen – Catterline, Stonehaven, Muchalls are some. North of Aberdeen the coast changes and there are miles and miles of sandy beach. There are some sites for rock pooling though – Rockend on Forvie NNR, Collieston and Peterhead Lido. WHEN? - Before you go check the tides. Tide times can usually be found in local newspapers and times for the next 7 days can easily be found on the Internet. There are about six hours between high tide and low tide, so try to time your visit so that you are there at low tide to catch sight of the things at the bottom of the beach before the sea covers them again. The rock pools nearest the sea, lower down the beach will have the most interesting life in them as they are generally bigger and deeper and are only cut off from the sea for a short time. WHAT? to take – You can enjoy rock pools by taking absolutely nothing at all and just be amazed by looking at things where they live. For a more detailed investigation the following items may be of use: • Appropriate footwear – In the winter, wellies obviously keep your feet dry but can be slippery. In the summer, beach shoes or sandals that can get wet are fine but watch those exposed toes. The best things if you have them are wetsuit boots. • A tub or bucket – clean, empty margarine tubs are great for seeing life that you collect and want a closer look at. • A net – tea strainers are brilliant for catching smaller beasties, or a small aquarium net. Large nets on long sticks can be a bit unwieldy and a hazard to others around you. • Wipes or gel – if it is not possible to get to a tap and soap, take something to wash your hands before you have anything to eat or drink after you go rock pooling. • A guide book Just remember the golden rules of rock pooling; -always go with an adult -do not touch the plants and animals as many rock pool animals can sting, bite and pinch -always carefully replace all overturned stones -do not pull seaweed off the rocks-it can take years to grow back -if you take any shells home make sure they are empty first, you never know what might be lurking inside! -tread carefully to avoid slipping on the wet rocks -please take your litter home with you or put it in a bin -keep an eye on the tide and last but not least -HAVE FUN .