A quick post to keep the blog going. Seaweed season has passed me by a bit, first because of the bad weather and second, when the weather was better, because I did not have much time to go out. I went snorkelling only twice in May in my usual (shallow) spot at Castle Beach in Falmouth. On the 13th of May the plankton bloom was in full swing: a (wannabe) photographers nightmare! Generally, the seaweeds at this point were already a bit ‘over the hill’. I managed to get a nice shot of Berry wart Cress Sphaerococcus coronopifolius though (above). I also glimpsed what I believe is Iridescent Drachiella Drachiella spectabilis under a rock overhang. The bright blue Bushy rainbow wrack Cystoseira tamariscifolia contrasted very nciely with the deep red of the Red rags Dilsea carnosa, I hope to get a much better picture of that (probably next year…).By the next snorkel session the 19th, the visibility was much better. Some photos of the green seaweed Codium sp., A Gelidium sp. (pulchellum?) and a patch of Slender-beaded coral weed Jania rubens growing epiphytically on Hairy sponge weed Cladostephus spongiosus with the very common species Ulva and Oyster thief Colpomenia peregrina (and others). Next, Beautiful Fan weed Callophyllis laciniata and another Berry wart Cress Sphaerococcus coronopifolius. Finally, three shots giving a general impression of the seaweed growth and what I think is Chipolata weed Scytosiphon lomentaria as well as a snakelocks anemone inbetween yellowed False eyelash weed Calliblepharis jubata. About the animals: there are some juvenile pollack around, as well as two-spot gobies. I saw a brown, flabby shape drifting through the water at one point and my first thought was that it was a seahare but it actually turned out to be a small clingfish (I could not get a photo unfortunately). There were quite some polychaete worms erratically swimming around in their reproductive ‘epitoke’ stage. The final photo shows one (with a Nassarius reticulatus in the background) which could be Perinereis cultifera.
Above the spot where I have been snorkeling all year at Tunnel Beach, between Castle- and Gylly Beach, in Falmouth (Pendennis Castle can be seen in the background). The best time to snorkel is before low tide, as when the tide comes in the viz gets worse. I try to aim for 50-100 cm above the low tide mark which is really shallow. This area is not a real rock pool but rather a gravelly zone between the rock pools proper and the kelp forest which begins past the last row of rocks on the photo. Last week I went snorkelling three times but only last Thursday had decent viz. The photos below show the abundance of pink Harpoon weed Asparagopsis armata, green Sea lettuce Ulva lactuca and new growth of Thong weed Himanthalia elongata and older plants covered in red fuzzy epiphytes. The old wireweed Sargassum muticum plants have died off and the remnants are covered in many epiphytes such as Juicy whorl weed Chylocladia verticilata, Cock’s comb Plocamium cartilagineum and the pretty Iridescent fern weed Osmundea truncata. However, there is new growth everywhere as well so, like Himanthalia, this species seems to have a half-yearly lifecycle. Below some Irish moss Chondrus crispus next to Wireweed. After that, lots of little fuzzy Falkenbergia growing on top of Discoid forkweed Polyides rotundus. This combination grows in a large patch and looks interesting but I struggled to get decent photos, as the dark seaweeds on very white gravel mess up the white balance big time. Next one or two different species of fine flat reds, the last probably Nitophyllum punctatum. The Bushy rainbow wrack Cystoseira tamariscifolia is dying off (here overgrown with Asparagopsis and Dictyota) but the related Bushy berry wrack C. baccata is doing well. Among its epiphytes Spiny straggle weed Gelidium spinosum (ID thanks to Seaweeds of the Atlantic facebook page members) which is also freeliving, and finally the green Codium fragile. One time, when the tide came in, the water was super oxygenated, and all surfaces were covered with small silver bubbles which was beautiful (and annoying as the camera lens was also covered). The following photos show a very different looking Codium fragile, C. tamariscifolia overgrown with Sea beach Delesseria sanguinea and more Thong weed.
Last week I went for a little swim at the usual spot at Castle Beach. The viz was nowhere near as good as last month, but still OK. There are schools of sand eels and sand smelt and I even saw an eel. The contrast between growing brown seaweeds and withering red seaweeds has become even greater. Below you see some yellowed Harpoonweed and a ‘forest’ of Thong weed covered in epiphytes. As the light was a bit subdued, I focused on the most shallow area. The bare parts of the rock are covered with barnacles, dog whelks, sting winkles and limpets. The seaweeds are mainly Serrated wrack Fucus serratus, Sea lettuce Ulva, Grape pip weed Mastocarpus stellatus, some Ceramium and Laver Palmaria palmata, as well as Dumont’s tubular weed Dumontia contorta.
Above an illustration of the decline of seaweeds: Juicy whorl weed Chylocladia verticillata all white and fuzzy (see for a more healthy looking plant this post from 2.5 months ago) on a bed of the common and pretty Discoid fork weed Polyides rotundus. There seem to be around 25 or so (larger) species that are common in these pools. Many of them can be seen in the two photos below (including a stray Bladder wrack, a species that dominates the shore just a meter higher): Below, a whole bunch of individual species. First, Sea beech Delesseria sanguinea, which must have washed up from under the kelp beds (too bad I did not get the entire plant in frame…). Second, a photo of Ulva with Chipolata weed Scytosiphon lomentaria. Third, the brown Divided net weed Dictyota dichotoma. Fourth, Slender wart weed Gracilaria gracilis. Fifth, False eyelash weed Calliblepharis jubata; this plant has grown quite large and has turned from dark red/brown to a much lighter brown. Sixth, the Falkenbergia stage of Harpoon weed Asparagopsis armata (see the third photo) on the right. Seventh, Red grape weed Gastroclonium ovatum. Finally, two photos of my favourite species the blue Bushy rainbow wrack Cystoseira tamariscifolia.
Less than 12 hours back in Cornwall and I managed to slide into the rock pools at Castle Beach in Falmouth this Saturday to see what the seaweeds looked like. There was a noticeable difference with only a week ago. The speed at which seaweeds grow, and decline, still amazes me. I managed to take my best photo yet, of Red rags Dilsea carnosa (surrounded by a whole bunch of other species), above. I made so many photos that I will split them over two posts, with some general ‘seaweeds scapes’ here and with individual species in the next post. The Sea lettuce Ulva has been taking over parts of the pools, turning it a bright green. The reds of the Juicy whorl weed and Berry wart cress and pink of Harpoon weed are less bright, and the Red grape weed and Fern weeds are turning ‘fuzzy’. Still, the seaweeds are much bigger and cover most of the seabed and it looks very exuberant. The Wire weed and the Thong weed (or ‘spaghetti weed’) Himanthalia elongata have been rapidly growing; the latter consisted of ‘buttons’ in January and are now a meter long, so must grow around a centimetre a day. The fronds are covered in flakes (which must be reproductive structures) that come off when you swim through them, clouding the water and so ruining the shot if you do not take it straight away. The sun came out more in the last photos, hence the different light (I have edited most (not all) photos slightly using standard Windows Photos, mainly by decreasing the highlights). More photos very soon!
A final post summarizing my experiences with seaweeds and writing this, I have regained my enthusiasm for trying to grow seaweeds in my aquarium. My New Years Resolution will be to get a proper marine planted tank going again! (The fact that the aquarium, currently devoid of seaweeds, looks less than great at the moment has made the decision to change it around easier as well…)
5. Some seaweeds establish naturally in the aquarium
I mentioned in the first seaweed post that it can be hard to ‘plant’ seaweeds in the aquarium but sometimes they just settle by themselves. One of my favourites, Chrysymenia wrightii (consistently misidentified as Dudresnay’s whorled weed throughout this blog…) started growing spontaneously from a rock:
This is currently happening with bright green Sea lettuce Ulva and what is probably Devil’s tongue weed Grateloupia turuturu. The outlet grid of the Tunze nanostream is a good place for seaweeds to settle it seems; I have currently a little pluck of Flax brick weed Chaetomorpha linum growing and had a couple of other species there in the past too. Spontaneous growth is of course the best way to get a seaweed aquarium going.
6. A list of Seaweed species I had in my aquarium
Perhaps of interest to a handful of people… I have tried to list all seaweeds I managed to identify and remember, and whether they did well (YES) or not (NO) in my unchilled aquarium (lighting spectrum and intensity used varied somewhat over time). Why some species did not do well I have no idea (see previous post); in some cases, seaweeds were eaten. I have not tried larger species such as Kelp as my aquarium is not that big.
Above: Green (Velvet horn), Brown (Wireweed) and Red (Harpoon Weed) seaweeds in the aquarium.
Solier’s red Stringweed Soliera chordalis – YES
Chrysymenia wrightii (no common name) – YES
Dulse Palmaria palmata – NO (eaten)
Harpoon weed Asparagopsis armata – NO
Common coral weed Corallina officinalis – NO
False eyelash weed Calliblepharis jubata – NO
Dumont’s tubular weed Dumontia cortorta – NO
Clawed fork weed Furcellaria lumbricalis– NO
Red grape weed Gastroclonium ovatum – NO
Bunny ears Lomentaria armentata – NO
Devil’s tongue weed Grateloupia turuturu – YES
Iridescent drachiella Drachiella spectabilis – NO
A tangle of different Red Seaweeds:
Estuary wrack Fucus ceranoides – YES
Serrated wrack Fucus serratus – YES
Bushy berry wrack Cystoseira baccata – NO
Bushy rainbow wrack Cystoseira tamariscifolia – NO (still my holy grail)
Wireweed Sargassum muticum – YES (this proved to be the easiest one of all to keep)
Common green branched weed Cladophora rupestris – NO
Flax brick weed Chaetomorpha linum – YES
Sea lettuce Ulva (lactuca) – YES
Velvet horn Codium tomentosum – YES
So 9 out of 21 species did OK in my aquarium which is actually not too bad (although I have forgotten a number of species that did not do well). Unsurprisingly, the invasive species were easiest to keep (5 YES in 16 natives, 4 YES in 5 non-natives; the difference is not statistically significant though).
Finally, I just wanted to mention that I have been updating the ‘links’ page recently. Regular commenter Marius has recently started a great blog about his new native marine aquarium with organisms collected at the west coast of Ireland: Irish Rockpool Aquarium Adventures, go check it out. A very nice rock pooling blog also is The Salty Scavenger which features loads of seaweed pictures. From now on, I will also register my rock pooling finds online here; with lots of volunteers doing that a great resource will be created that can be used for protecting marine habitats which of course is very important! I have also added a bunch of really useful links to facebook pages, for instance the ‘Coldwater Marine Aquarium Owners‘ group page.
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:
It was too cold and windy to spend a lot of time on the beach, so I took a closer look at my seaweed catch back home. I was amazed at the diversity of organisms growing amidst the weeds. A lot of them are easily overlooked when rock pooling as you need some time (and preferably a comfortable seat) to find them. Below Bushy rainbow wrack with epiphytic False eyelash weed and Pink plates Mesophyllum lichenoides (I will not give the Latin names of species described in preceding posts for brevity). Some bright green sea lettuce Ulva, a grey topshell Gibbula cineraria, a snakelocks anemone Anemonia viridis and in the middle a bright orange colony of the tunicate Botrylloides leachi: I found many large Breadcrumb sponges Halichondria panicea but the picture I took did not turn out to be in focus. I do not know what the organism below is, perhaps a bryozoan (please feel free to comment!). I am not sure what this is either! Dog whelk Nucella lapillus eggs (I now also notice a tiny brittle star in the middle): Egg cases of the thick-lipped dog whelk Hinia incrassata: A small snakelocks anemone; interestingly enough all of these were the green variant (with purple tips) and there were none of the pinkish ones. I have read some interesting notes about aggressive behaviors between the two types, something to look into for a future post. A Marbled Crenella Modiolarca tumida, a tiny bivalve typical of seaweed holdfasts: A tiny White tortoiseshell limpet Tectura virginea: I saw something creeping out of the seaweeds on the floor out of the corner of my eye: a small Long-legged spider crab Macropodia rostrata. This species adorns itself with seaweeds for camouflage: