Violet Sea Snail

An hour of beach combing today at Praa Sands, chosen because it is a reasonably long beach facing the prevailing wind. A fair amount of Goose Barnacles smattered among the rocks. On the strand line, bits of seaweed and lots of plastic rope fragments from fishing boats (which were duly picked up). Not expecting anything spectacular, my eye was caught by a tiny bit of violet, which proved to be a Violet Sea Snail! We had only found a Janthina janthina once before in our ten years in Cornwall but that was an empty shell whereas this still had its bubble raft. Janthina floats at the surface off the open ocean under this raft and therefore is part of the ‘neuston’ (or ‘pleuston’). It is a predator of other such purple ocean surface dwellers such as By-The-Wind Sailors Velella velella, and the Portuguese Man o’ War, Physalia physalis. It was tiny, the shell measuring only a centimeter or so. There were many By-The-Wind Sailors too, and these were just as small or smaller (usually they are 4-8 centimeters or so). I did not use a flash (looks to artificial), keeping ISO at 200 and f/7.1 I had to go down to 1/30s for shutter speed which was doable leaning on the beach. The protoconch is nice and sharp when you zoom in.

Macro Musings

Foul weather in Cornwall at the moment (it is November, so no surprise there!). Not tempted to go in the water but still wanted to take photos, so I spent some time on the foreshore of my village Flushing looking at Flat Periwinkles (Littorina obtusata). This species is very common, and the only snail that actively crawls about above the waterline. The trouble with macro photography is that with a small aperture, the depth of field is large and everything is in focus, but this includes the usually cluttered background that takes away from the subject. With a large aperture, it is possible to get an aesthetically pleasing, soft focus bokeh background, but the depth of field is much smaller, and too much of the subject is blurry (see the pic on the right). I tried my hand at focus stacking, in which the camera takes a bunch of photos each with a different part of the subject in focus, and then merges them so the depth of field is greater (whilst still having the out-of-focus background). This proved too difficult with a handheld camera (especially on my knees in seaweed). I therefore reverted to ‘normal’ manual photography and it was fun to practice. However, I did not manage to improve on my best Flat Periwinkle photo I took when I first got my Olympus….

St. Cuthbert’s Cave

Holywell Beach on the North Coast of Cornwall is known for a small sea cave which houses a ‘holy well’. According to Mabel Quiller-Couch, in her 1894 book “Ancient Holy Wells of Cornwall” in 995 AD the bishop of Lindisfarne, Aldhun, was bringing the remains of saint Cuthbert back to Ireland. Blown off course in a gale, he was left stranded in Cornwall where he settled and built a church dedicated to St Cuthbert. After some years however, an oracle instructed Aldhun to return the relics of St Cuthbert to Durham. As he was leaving from Holywell Bay, the saint’s bones touched the side of the well, giving the spring its magical healing powers. In medieval times, many people flocked to this cave to seek out the healing powers of the spring.

I was in the area this week when the tide was low (at high tide the cave is completely flooded, so you have to check the tides!) and decided to bring out the fisheye lens and a tripod to take some long exposure pics. They came out all right. There are more colourful photos available online, but my suspicion is that these use artificial light and sometimes also some enthusiastic post-processing. By using the longest possible exposure time on my camera (Olympus OMD E-M1markII), a full minute, I was able to let enough light into the camera. This enabled me to use f/18, allowing great depth of field, and ISO200, meaning little noise.

The formations result from a rare (in Cornwall) limestone deposit in the roof of the cave. Slightly acidic rainwater percolates through this limestone, dissolving calcite and becoming enriched in calcium bicarbonate. When the water drips down the rocks, the process is reversed and calcite precipitates, especially in areas where the water moves a little, causing CO2 to gas off. This results in the dam-like rimstone (or gours) formations. The tiny ‘rice terrace’-like formations on the dams are called microgours. I’d like to go back one time to experiment more and also to take some macro photos of the microgours and colourful microbes.

Miscellaneous Macro

I have not posted a lot this year; in part just because I have not been out as much as I hoped I would, and in part because I had some technical difficulties (I had to sent back a malfunctioning strobe and am also having snoot troubles). As a result I have not gone scuba diving and did not see much of the rock pools either. I managed to take some macro shots over summer though that are worth a quick post. Above a Cushion Star Asterina gibbosa on a colony of the star ascidian Botryllus schlosseri. Below one of my favourite little molluscs, the beautifully patterned White tortoiseshell limpet Tectura virginea. Another tiny mollusc, is the Needle Whelk Bittium reticulatum. The Variegated Scallop Chlamys varia is also common (under rocks) and can be nicely patterned when they are small. Finally some other tiny critters: the Flatworm Leptoplana tremellaris (I like their beady little eyes) and the Bryozoan Disporella hispida.

Jellyfish

It is the time of year where the rock pools look less attractive (for an example see this old post) and jellyfish appear in the sea beyond. As they are pretty and slow moving, they make for excellent subjects and so I have ventured out over the kelp recently to look for them. I now have a reliable INON D-200 strobe (actually I have two such strobes, it is just that the second arrived 6 weeks ago but not its fibre optic cable…) which makes a huge difference in the types of shots you can take. Photos taken using natural light only can be pretty (see for example here for previous attempts) but a strobe just opens a whole new range of possibilities. I was quite pleased with myself with the shot above of a Compass Jellyfish that seems to float in outer space. Here, the strobe lights up the jelly (which is really close in front of the camera) but it cannot light the ocean behind. Using a fast shutter speed, the ambient light (that would make the water blue) is not let into the camera, resulting in a black background. An exception is the bright sky, which is visible in Snell’s Window, and which looks a bit like a planet against the black background. Of course, even with using a strobe you can choose to let in ambient light, leading to more conventional shots such as the one below (however the jellyfish is a bit further away and not very nicely lit up by the strobe):

By pointing the camera downwards and getting rid of much of the sunlight, the fast shutter speed black background effect is even stronger, even on a sunny day. An example is the Moon Jellyfish below. Btw, I have touched these photos up with the generic Windows photoviewer (a poor man’s Adobe Lightroom) whch performs quite well. It is however tricky to get rid of some of the backscatter (particles in the water that light up because the strobe is incorrectly positioned, illuminating not just the subject but also the water in between subject and lens). This effect can be seen above the jelly in the second photo even after editing in Windows Photo:

It is great fun to practice photography with these jellies. In principle one strobe is enough (and many pro photographers recommend to try shooting with a single strobe). However, there are situations where two strobes are clearly better, namely when a subject needs to be lit up from two sides. The photo below was taken with the camera turned 90 degrees with the strobe to the left side (notice the remaining backscatter after using the clone stamp tools in Windows Photo). Having had another strobe to the right would have avoided the shadows (but probably have added backscatter!):

Some more shots below. The visibility has been poor lately but I hope to be able to practice some more over the weekend.

rockpool impressions

Some pics from last week when the weather was good. The pools are golden brown at the moment (especially in the sun) with wire weed, thong weed and kelp dominating and mainly pinkish harpoon weed on the bottom. There are many schools of pollack along with the occasional school of young mullet and sand smelt. (One sand smelt was not in very good shape so I could get very close to take a good look.) These pics are taken using natural light. Nothing too special but I just wanted to post a bit more this year!

Nudibranch

Two entries back I posted photos of the Goby egg-eating seaslug Calma gobioophaga. Last week I was lucky enough to spot its cousin, Calma glaucoides, who is a bit less fussy and eats different types of fish eggs, as well as cephalopod eggs. I found it by turning over a rock whilst snorkeling in a very shallow (<50 cm!) pool. Next to a depleted patch of clingfish eggs, it was circling around, busily depositing eggs of its own. A fantastic surprise, and I really need to get on with recording such findings.


Snorkel Adventures

The sun is shining (most days) and the water has warmed up, so ideal conditions for a bit of snorkeling. I have been out at my usual spot in Falmouth (rockpools and kelp forest) and my local beach in Flushing (seagrass) (and yes, I really count myself lucky every time that l live here!). The last couple of times I have brought my son along, as he is now old enough (nine). He is a nature freak just like his dad, actually probably more so! I need to get him fins and a weight belt soon, but he has been doing fine in the water already.

The photos above and below illustrate the state of the rock pools at the moment: quite brownish with the Sargassum and Himanthalia growing everywhere. The red, pink and purple species have largely disappeared (apart from Harpoon weed) and there is quite a bit of green Ulva growing. The water teems with juvenile pollack in the rock pools and schools of sand eels a bit further out. Diving over sandy patches, you can see the latter species shooting out of the sand en masse. It is crazy how such a silvery pelagic fish can also burrow in the sand. I guess it does take its toll, as there are quite some dead ones to be seen too.

The Flushing snorkel site is very different, no (deep) rockpools, only a little bit of kelp but with a very healthy patch of seagrass. No catsharks or thornback rays when we went in, just the odd small sea bass. There are many small Snakelocks anemones on the seagrass. I used to think that it was mostly the purple form that did this but I now noticed that most were the green variety, so the morphs do not seem to differ in this respect after all. One anemone had ‘caught’ a crystal jellyfish (an Aequorea medusa). Not sure if it was in the process of being digested or just ‘stuck’.

I have played around with my new INON strobe, which works a lot better than my old strobe. I have ordered a second one for Wide Angle photos too….(as you can see there is quite some backscatter in the pic of the Shore Crab above). I will need to get back to some shore diving to make optimal use of two strobes, as I am too lousy a freediver to get the lighting and exposure right in one breath!

new strobe

Long time no post! Due to a combination of not-so-good weather and work I have not been in the water much the last few months. I attempted some seaweed photography but most times the viz was bad; the one time the conditions were great, somehow all my photos turned out to be a bit meh and I could not be bothered to post them. (For some older shots on seaweed diversity see here, and many older posts as well.) Anyhow, my exciting news is that I finally bought a new strobe (an INON D-200 for those who are interested) because my old Sea&Sea strobes just proved to be too temperamental. Something I should have done a long time ago, but the thrifty Dutchman in me just never pulled the trigger. I have now taken it out twice this weekend and it works like a charm! Now I just need to practice, as it is actually still very hard to go from an OK photo to a truly good pic. Above a shot of a baby urchin Psammechinus miliaris. The true stars of the weekend however were nudibranchs.

A very special find (shown to me by fellow rockpool photography enthusiasts Martin and Greg) were two Goby egg-eating seaslugs Calma gobioophaga. This tiny species can only be found on the goby eggs it eats. With such a ‘niche niche’ and with very good camouflage it is no wonder that reports of this species are rare. A fun fact: its protein-rich diet means it does not have to poo and it therefore does not have an anus…The rock with the eggs and nudis was very shallow and so it was a challenge to get the port of the camera housing under water. Luckily Greg assisted with pointing out the nudi and holding my strobe in place. Freshly hatched goby fry could be seen hovering above the eggs (the fact that a predator was munching through their brothers and sisters might have triggered some of the hatching). The cerata (the fleshy lobes on the nudi’s back) seem to have two goby eyes in them to make them better blend in!

Finally, two other nudibranch species, neither very colourful. Both are predators of anemones: first the largish Grey sea slug Aeolidia papillosa and second the smaller species Aeolidiella alderi. Both adequate shots but I need to practice to make them truly good. I will probably buy a second INON strobe so I can practice wide angle shots as well when diving. I hope to go out a lot more during summer and will make sure to post here about my finds and progress!

Macro

The weather has been horrible lately, with three storms coming in straight after each other. On the upside this means that there is good potential for beachcombing, but alas, the one beach on the North Coast we checked was as clean as a whistle, just sand! So here are some photos from a few weeks back when the weather was good better. On top a Spotted Kaleidoscope Jellyfish (Haliclystus octoradiatus), about 15 mm across, on some Irish Moss seaweed. Please see this site for more information on these beauties; there are several species in our rockpools, but you have to develop a bit of an eye for them! Some other pics below: Blue-rayed Limpets (Patella pellucida) on kelp and a Thicklipped Dogwhelk (Tritia incrassata (when I was young Nassarius incrassatus…). Still need a lot of practice with the strobe, these shots I was very happy with, but most were way off the mark somehow. Looking forward to spring!