More seaweed photos, taken a couple of days after the ones in the previous post, when it was overcast and the water was less clear. The photos are not as good, but there are still a lot of interesting species to see. Below some photos showing the diversity of species next and on top of each other. In the last two months, most species have been growing quite a lot. There are quite large patches of Slender-beaded coral weed Jania rubens. Bushy rainbow wrack Cystoseira tamariscifolia plants are completely overgrown with all kinds of epiphytes, seaweeds, sponges and colonial tunicates, and often have a Nursehound egg case attached. Next, photos of individual species. First some flat reds: Leafy rose weed Rhodophyllis divaricata, Beautiful fan weed Callophyllis laciniata, Branched hidden ribs Cryptopleura ramosa (probably), the invasive species Devil’s tongue weed Grateloupia turuturu and Under tongue weed Hypoglossum hypoglossoides. After that, two species that look a bit similar: left the reddish Discoid fork weed Polyides rotundus and right Clawed fork weed Furcellaria lumbricalis. The former is one of the most common species (also on the photo above it) but difficult to photograph as it usually sits on the white sand. After that, Juicy whorl weed Chylocladia verticillata. Last, two quite unassuming species: Black scour weed Ahnfeltia plicata and Sea flax weed Stypocaulon scoparium. Identifications made possible using the must-have Seasearch Guide to Seaweeds of Britain and Ireland, David Fenwick’s excellent aphotomarine website (and personal communication) and the good people of the Seaweeds of the NE Atlantic facebook group (any mistakes are my own).
Last weekend I took a little stroll on my local beach in Flushing and had a quick look at the variety of red seaweeds washed ashore. I saw some that I did not know, some that I knew, and some that I thought I knew….
I have recently joined the facebook group ‘Seaweeds of the NE Atlantic‘ and so immediately asked the experts for some help in identification. It turned out that the only one I correctly identified was the one on the bottom right: Solier’s red string weed Soliera chordalis. This (invasive) species did well in the aquarium and so did the one on the top right, which I always thought was Dudresnay’s whorled weed Dudresnaya verticillata but it isn’t! It is actually Chrysymenia wrightii, which is also an invasive species. Moreover, my ID of the bottom left species was also wrong: not Fine-veined crinkle weed Cryptopleura ramosa but Beautiful fan weed Callophyllis laciniata (I should have known this as I have found crinkle weed in France this year…). The small flat seaweed on top is Cock’s comb Plocamium cartilagineum. The dark mop top left could not be identified based on this picture so I have to go back to take a better one. So dear reader be warned and take my identification of seaweeds in previous posts with a grain of (sea)salt!
In addition to animals, loads of different seaweed species could be found washed up on the beach in Pleneuf-Val-Andre:
Some of the species would look great in the aquarium I am sure. For instance Fine-veined crinkle weed Cryptopleura ramosa:Pestle weed Gigartina pistillata: (EDIT 2017: does not look like this species at all, be very suspiscious of my seaweed ID skills in older posts please!)Maybe a Plocamium species, I am not sure. I really like my Seasearch Guide to Seaweeds of Britain and Ireland, but it does not contain a key and I find it hard to determine some species based on a photograph.What would be great is to have a seaweed key app. I saw a great one this weekend for trees: leaf snap: take a picture of a leaf with your phone or tablet and it automatically gives you a list of best hits based on the outline (and perhaps colour, I don’t know), it worked really well. Seaweeds (actually pretty much all organisms) are too complex in shape, size and color for this. However, I could see an app working where the first screen would give you a number of pictograms, eg ‘dark encrusting reds’, ‘chalky reds’, ‘feathery reds’, ‘fan-shaped reds’ etc. After touching a first pictogram, new ones would appear, for instance to select the branching pattern, ‘irregular’, ‘whorled’, ‘opposite’ or ‘alternate’ and so on. Instead of such a purely dichotomous approach, it could also be possible to be presented with a wide variety of pictograms describing different properties (eg, colour, overall shape, texture, location on the shore), where it is possible to skip properties you are unsure about and still go ahead with the next steps. This would be a brilliant resource and help me identifying weeds such as this one:Anyway, a final seaweed (there were many, many more but this one I immediately recognized): Sugar Kelp Saccharina latissima. It is surrounded by various species of flat and tubular Sea Lettuce Ulva: