All right then, another post with me fiddling around photographing seaweeds. Composition remains difficult; the next four photographs illustrate this. The diversity of colours and shapes compensate somewhat for it though. I think that a wide-angle lens is crucial to get better pictures: you can get close to the subject (important, as the water is not always crystal clear) whilst still getting a ‘panoramic’ view. Cameras such as the Sony RX100 in an underwater housing can be combined with such lenses (‘wet lenses’ which go on the housing rather than in). Camera, housing and a macro and wide-angle lens will set me back £1000 or so though, so maybe not. In any case there is still plenty room for improvement with the simple Canon Powershot, preventing overexposure for instance. I use Picasa to add some contrast, crop and straighten btw.
Photographing through gulleys to create some depth makes things a bit more interesting (first picture). The second picture shows an overexposed background and a dark foreground but if properly exposed and in focus this sort of shot could be nice. Shots that are half reflection make things psychedelic and quite cool. This effect works well for Dumont’s tubular weed Dumontia contorta which is common highest up the shore (third picture). It is challenging to capture the beautiful blue-green colour of the Bushy rainbow wrack Cystoseira tamariscifolia as it is caused by iridescence, i.e. physical surface properties (see this old blog post from my work blog for some more info). It thus depends on the angle of view whether these beautiful colours can be seen. In the fourth picture you can see that the seaweed is a dull brown, but its reflection underneath the water surface does reveal the blue colour. The last picture demonstartes the different colours and textures well, but it is overexposed unfortunately.
Tag Archives: Canon Powershot
More Jellies
A second, long snorkel session at Gylly Beach yesterday. Loads of Sand eels, no cuttlefish but there were a couple of beautiful Compass jellyfish Chrysaora hysoscella around, with tentacles up to a meter long (first pic). Smaller and less visible was Aequorea forskalea or A. vitrina (second pic)*. A close relative of this species gave molecular biology ‘green fluorescent protein‘ (gfp). 
This time we swam out a bit further, over the sandy bottom which seems quite lifeless compared to the rocky kelp forest. However, the fauna is very different here so it was definitely worth it. I found my first Sea potato Echinocardium cordatum (about to be eaten by a Spider crab). Near the buoys, at around nine meters depth or so there was (sparse) seagrass. Back on the beach I noticed that my lumix camera was flooded. I was somehow convinced that it could go up to ten meters deep but actually the sticker on it quite clearly stated that it was waterproof only up until three meters….Ah well, I will have to switch back to my Canon Powershot with waterproof case then.
*= From the facebook group NE Atlantic Cnidaria: “A. forskalea : up to ca 120 marginal tentacles, usually fewer than the radial canals but ranging from half to twice as many; radial canals 60-80; max diameter ca 175mm” and for A. vitrina: “60-100 marginal tentacles, three or more times the number of radial canals; radial canals 60-100; max diameter ca 100-170mm”.
Cornish Coral
A couple of weeks back I went for a boat trip and snorkel over Maerl beds with friends on the other side of the Fal Estuary, just north of St. Mawes. I did not post about it at the time, as my photographs were quite crap and I reckoned I could go back to try and come home with something better. However, there hasn’t been any time for that, nor will there be in the near future, and as it was such a cool experience I reckoned it would be nice to write a little post about it for now anyway. The beach was fringed with sea grass, but the Maerl beds started very near the coast, at around two meters depth at low tide. Maerl is something special; it must have taken early biologists a while to figure out whether it was mineral, animal or plant. It is actually a calcareous alga that (very slowly) grows in fist-sized nodules or thalli. The Fal and Helford estuaries are one of the few places in the country where it occurs, and the Maerl beds here are under threat of dredging. Although Falmouth has the third deepest natural harbour in the world, big cruise ships cannot land close to the town centre which makes it unattractive for ships to stop. Falmouth would be a very pretty last port of call sailing west and cruise ships are of course good for business, hence the dredging plans. I will save the debate on economy versus conservation for a future post, as it will require a lot more text. I was able to take some pictures of the Maerl with my old Canon Powershot in plastic housing before the new batteries decided to quit on me prematurely:
As you can see the Maerl really looks more like a coral than a seaweed (and dead pieces of Maerl form a type of coral sand, see here and here). It provides an ideal structured habitat for all kinds of organisms to live in and on (for instance fine seaweeds and snakelocks anemones). Besides various fish, crabs and sponges and small things darting to safety in general, we saw a big hermit crab in a Buccinum undatum shell with the large anemone Calliactis parasitica on top. Very cool, and apparently not very commonly encountered (this was of course after my batteries had run out). What was striking as well, were the very large (one of them measured half a meter across), very fat and very pale Spiny starfish Marthasterias glacialis:
Maerl with a sponge growing through it (or possibly the other way around):
Maerl is protected, so not an option for the aquarium, although I am sure it would make for a fantastic looking display (moreover potentially a very stable display as Maerl is not seasonal but grows for centuries). Hopefully more and better pictures later this year!
An Bollenessor 