At Open Hall I snorkelled around the wharf. A wharf that just looks like hundreds of others. Some of concrete and stone but most of wood (often filled with stones for reinforcement). Some modern, some derelict. The latter are very photogenic!
Growing on the wharf and rocks: common southern kelp, Laminaria agardhii. It grows to 3 m and its blade has ruffled edges in spring and summer.
What looks like hairs are hydroids (Hydrozoa), animals related to sea anemones and jellyfish. Bigger brown seaweeds are often overgrown with hydroids, moss animals (Bryozoa), colonial sea squirts (Tunicata) and other - especially red - seaweeds.
I am not entirely sure about the species. It looks a lot like sugar kelp (also sea belt; NL: suikerwier), Saccharina latissima (formerly known as Laminaria saccharina). As Gosner (1978) quotes in Peterson's (see literature): 'L. saccharina is a problematic species distinguishable only by microscopic section; some authorities consider L. agardhii a form of this species.'
There is a lot of study in the taxonomy of seaweeds and consequently in their nomenclature. You can wake me up in the middle of the night and I could tell you the Latin name of sugar kelp. But now even this name has changed. See the link at the right side of this page for the most recent Latin names.
The blades often have a ragged look. Sugar kelp is eaten by snails but the lesions are foremost caused by battering waves.
Another species of the Laminariales: horsetail kelp (or oarweed, NL: vingerwier), Laminaria digitata.
And again a member of the order of Laminariales: dabberlocks (also edible kelp), Alaria esculenta. In Europe you will find this species only on exposed rocky shores. Click here for one of its relatives: Undaria pinnatfida.
The third member of the Laminariales: smooth cord weed (GB: bootlace weed, NL: veterwier), Chorda filum. It grows up to 4.5 m but is no more than 6 mm thick.
Left: sugar kelp. This specimen is quite thin, opposed to the more common leathery ones. As with a lot of seaweeds: the habit of growth is quite variable.
Dulse, Palmaria palmata (NL: rood lapwier). From Gosner (1978): 'Dulse, one of the edible seaweeds, is still harvested in the Canadian Maritimes and the Bay of Fundy, and packets of dull-red dried weed may be found in specialty stores. The texture of fresh dulse has been compared to salted rubberbands but improves on drying.'
A lot of seaweed specimes are commercially collected and cultivated around the world. The hankering for ecofriendly products will only increase the demand.
Salvage: this is where I had my second snorkelling trip. I found it rather poor, but maybe that was due to the amount of fresh water pouring out into the bay.
One of the top predators of seaweeds: green sea urchins, Strongylocentrotus droebachiensis. They grate almost every - not too large - organism off the substrate.
It seems that the rather calciferous coral weed (NL: koraalwier), Corallina officinalis, is not juicy enough for sea urchins.
Possibly black whip weed (NL: zweepvormig zeekoord), Chordaria flagelliformis.
Typical 'monoculture' seaweed growth: almost all the specimes in the small tidal zone belong to the Fucales.
A bay near Durrell at low tide with the same typical algal growth. At first it looked like coasts I know from France, Great Britain, South Africa, New Zealand an the west coast of Canada. So I thougt: excellent coast for beachcombing. You just have to lift the seaweeds to find crabs, starfish, sea anemones, snails etc. But unfortunately I just found some snails and a few little crustaceans.
The most common Fucales: in the centre bladder wrack (NL: blaaswier), Fucus vesiculosus and left knotted wrack (NL: knotswier), Ascophyllum nodosum. Both seaweeds have air bladders to keep them upright at high tide.
The 'bubbles' in the centre aren't air bladders but so called receptacles: reproductive bodies.
Knotted wrack has a single air bladder. This seaweed lives almost exclusively on sheltered shores. The bigger the air bladder, the more sheltered its environment.
As for identification: are you a fan of Science Fiction and Startrek? If so, then you are familiar with the tricorder. I expect that one day we will beachcomb with a DNA-tricorder in our hand for easy identification of organisms.
Possibly gut weed (NL: echt darmwier), Ulva intestinalis (formerly known as Enteromorpha intestinalis). Ulva's are hard to identify. One of the species that makes 'rockcombing' hazardous: green weeds like these make rocks very slippery.
With thanks to Dr. Herre Stegenga, National Herbarium of the Netherlands, Leiden University Branch, for his assistance.
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