Tag Archives: marine algae

Seaweed Strands with Crinkled Kelp

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Thick mats of seaweed wash ashore on beaches along the Jurassic Coast. Dead seaweed is often automatically viewed as horrid, unsightly, and a nuisance – but if you pause and look, there is beauty in it. There are many types of seaweed to be discovered in the masses on this strandline. Their fronds intertwine in a kind of accidental natural weaving. Each species has its own characteristic shape, texture, and pattern. Their combined presence forms greater abstract designs of infinite variety, the individual fronds making strands or threads as in a tapestry. The puckered patterns of the crinkly Sugar Kelp stand out as the most decorative features of the assemblage. The colours change from deep olive brown to golden yellow and cream as the algae decompose. The textures range from leathery to satiny, from slimy to crispy depending on moisture content. Opaque and hardening on exposure to air; or translucent and soft when floating in shallow water rock pools.

Studland Soft Seaweeds

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Brightly coloured seaweeds were washing ashore at Studland Bay in Dorset on 21st May 2017. Isolated clumps of vivid red, green, and brown soft seaweeds, that looked attractive floating in the clear shallow water, or scattered individually on the yellow ribbed sand, soon accumulated into thick solid multi-coloured mats undulating on the water’s edge. When a mat of algae like this is pushed high with the rising tide, and left stranded on the upper beach, it decays rapidly to become what the human eye perceives as a rather smelly, ugly mess. For every other organism large or small on the beach, rotting seaweed is a marvellous bonanza of food and shelter, which also helps to stabilise the sandy beach for further colonisation by plants.

Seaweed at Rocquaine Bay

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Seaweeds growing on a mooring rope at low tide

Sand-filled embayments occur among the rocky outcrops on the wide sweep of Rocquaine Bay. This bay is on the west coast of the Channel Island of Guernsey. The embayments are strewn with mooring chains, ropes and buoys that provide good anchorage points for small fishing boats, leisure craft and seaweed.

Velvet Horn Weed (Codium fragile) was growing profusely on one particular mooring rope this autumn. It was also living in rock pools further north on the shore. I was surprised to see it in such abundance because it seems to be one of the less common marine algae on the Dorset coast where I had seen it only a couple of times before. Its dark green branched fronds have an unusual spongy texture due to a thick covering of fine “hairs”. The Velvet Horn dominated for many metres along the rope towards the blue buoy but elsewhere it combined with a wide variety of seaweeds such as Irish Moss (Chondrus crispus), Toothed Wrack (Fucus serratus), and an assortment of filamentous red and green algae to cling in decorative clusters on the rope.

Seaweeds growing on a mooring rope at low tide

Seaweeds growing on a mooring rope at low tide

Seaweeds growing on a mooring rope at low tide

Seaweeds growing on a mooring rope at low tide

Seaweeds growing on a mooring rope at low tide

Seaweeds growing on a mooring rope at low tide