Our rocks are of varying hardness and this makes a superb environment, the differences forming cracks and crevices, overhangs and caves, to explore. It also makes great rockpools. The tectonic forces that shaped the jagged cliffs also define the rocky shore, many of the rocks are on edge, pushed upwards. This creates differences in height and so light and shade, water currents and desiccation levels vary hugely, this means one side of the rock is different from the other. Rocks offer a solid substrate to attach, weeds, anemones, molluscs, sponges, bryozoans and squirts all live here. These in turn feed crabs, oystercatchers, sea slugs, worms and many creatures. The rocky sections of our shore are the most diverse, especially if these are at the low water mark. Mobile organisms move with the tide, most hunt or graze when the water is in, this avoids predation by birds, desiccation and overheating in the sun. The communities found are also affected by the interaction of freshwater flowing over the beach, it is not always instantly apparent but the water draining from pool to pool can be from the land rather than seawater (mussels, egg wrack, Ulva indicate this). This creates a more green algae based structure.
Seaweed dominates rocky bits, often in zone bands, these are referred to as biological tidal zones. Serrated wrack in the low tide, the bladder in mid and spiral and channel wrack in the upper. The leafy reds also tend to be at very low water along with kelps, sea oak and grape pip weed. This is further complicated as some require the permanent cover of water so are only in pools (red paints, coralline algae, tuning fork weed). Zonation is extremely complex and on our shore even more so due to the fantastic geological formations. A high rock 50 meters down the beach from the cliff can have the same species as the cliff despite standing in deep water. A deep pool high on the beach the same species as the low water areas, you just never know what you will find here.
Where the rock is away from direct sunlight it can support a huge biomass of organisms, many of these are microscopic, a film of living matter covers most rocks. This changes if the rocks are mobile, as they rub they displace organisms, so this increases the habitat diversity if both types of rock exist. The extreme low tide zone exposed on the biggest spring tides, is a rich hunting ground but you need to be quick the creatures here will hide as the water drops, so often turning stones is required. Please be careful doing this lift them cleanly to avoid crushing anything under, and return them the right way up. If a rock is held in place do not dislodge it, the action of the tide is fierce and a rock that is then able to roll around will quickly destroy anything that lives on it. The difference between plant and animal becomes a little bit blurred in the sea, many things you find will be hard not just to name but also to even place in families let alone kingdoms. Rock pools will contain blennies, gobies, shrimps, and many others, a bit of bacon or offcuts of fish are a great way to tempt these out from their hiding places. Tie it on a bit of string or they will quickly carry it away or make a bottle trap by cutting off the top end of a bottle turning it around and pushing it back in. Put the bait in this.
Seaweed dominates rocky bits, often in zone bands, these are referred to as biological tidal zones. Serrated wrack in the low tide, the bladder in mid and spiral and channel wrack in the upper. The leafy reds also tend to be at very low water along with kelps, sea oak and grape pip weed. This is further complicated as some require the permanent cover of water so are only in pools (red paints, coralline algae, tuning fork weed). Zonation is extremely complex and on our shore even more so due to the fantastic geological formations. A high rock 50 meters down the beach from the cliff can have the same species as the cliff despite standing in deep water. A deep pool high on the beach the same species as the low water areas, you just never know what you will find here.
Where the rock is away from direct sunlight it can support a huge biomass of organisms, many of these are microscopic, a film of living matter covers most rocks. This changes if the rocks are mobile, as they rub they displace organisms, so this increases the habitat diversity if both types of rock exist. The extreme low tide zone exposed on the biggest spring tides, is a rich hunting ground but you need to be quick the creatures here will hide as the water drops, so often turning stones is required. Please be careful doing this lift them cleanly to avoid crushing anything under, and return them the right way up. If a rock is held in place do not dislodge it, the action of the tide is fierce and a rock that is then able to roll around will quickly destroy anything that lives on it. The difference between plant and animal becomes a little bit blurred in the sea, many things you find will be hard not just to name but also to even place in families let alone kingdoms. Rock pools will contain blennies, gobies, shrimps, and many others, a bit of bacon or offcuts of fish are a great way to tempt these out from their hiding places. Tie it on a bit of string or they will quickly carry it away or make a bottle trap by cutting off the top end of a bottle turning it around and pushing it back in. Put the bait in this.