diving

Having a diving certificate, being passionate about marine life and having lived in Cornwall for the past few years, it was a bit of a crime to not have been diving (bar a single dive last year). Last week I had the opportunity to join some experienced divers and went for two dives. The first dive was at local spot Silver Steps in Falmouth. We did not go deep (8 meters or so) and could stay in for over an hour. We spotted some cuttlefish (too shy to be photographed), a Greater pipefish Syngnathus acus and two Snake pipefish Entelurus aequoreus. A picture (made with my recent Canon Powershot purchase) of me (looking rather angrily) holding the latter species:IMG_0131For the second dive, we went to Porthleven, west of the Lizard peninsula and sheltered from the easterly winds. It was hard to figure out where to best enter the water; east of the village the cliffs seemed a bit high. In the harbour itself we still had to clamber of some rocks and then had to swim out a bit first to stay out of the way of any passing boats:IMG_0150This dive site was prettier than the first one: there was a larger rock face covered by seaweeds (notably the large Desmarestia ligulata that was completely absent from Silver Steps) with a clean sandy bed beneath (loads of Two-spotted gobies around as always). Lobsters Homarus vulgaris seemed to be relatively common, as we did not particularly look hard but found two individuals (as well as a Spidercrab Maja squinado):IMG_0168

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IMG_0191One of my dive buddies pointed out a fish, I enthusiastically but mistakenly chased a small Bib Trisopterus luscus; much to their bemusement they were actually pointing at a Red gurnard Aspitrigla cuculus. It was not shy at all:IMG_0176

IMG_0178Finally, when getting out of the water, amongst the Shannies I noticed a beautiful Montagu’s blenny Coryphoblennius galerita:IMG_0203

Snorkelling at Silver Steps Part II

This snorkel session was also the first time I took a proper look underneath the kelp. Mowing through this forest is very interesting. Besides the gobies and starfish, there are a lot of sponges, bryozoans and hydroids to be seen. A picture from this ‘turf’ with many hydrozoans and a larger erect bryozoan (perhaps an Alcyonidium species?); these are groups I know very little about. A photo beneath that of some worms Bispira volutacornis, very beautiful:P1040002

P1040017The kelp is covered by a not so pretty, large, fluffy brown seaweed which might be Pylaiella littoralis (first picture). Large bushes of the slightly iridescent Dictyota dichotoma were also common, this is a species I have never seen in rock pools (second picture). The rocks underneath the kelp are also home to many red seaweeds, notably Sea Oak (I have to get back for some pictures).

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P1030987In the deeper channels there were many Mermaid’s tresses Chorda filum, more than five meters in length. The shallow rocks were covered with Thongweed Himanthalia elongata and Grape pip weed Mastocarpus stellatus with assorted epiphytic tufts of fine red seaweeds.  P1030974

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“onderzeesche landschappen”

Thus the old Dutch spelling of “Undersea Landscapes” (the English word ‘landscape’ comes from the Dutch word ‘landschap’ btw). I bought some Liebig Cards online; these free collectible cards were supplied with stock cubes and included many biology-themed sets. Besides this set (1936), I also found a seaweed set (1937, in French), cool!IMG_1332 IMG_1333

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Science in the square

I helped out last Friday at the University of Exeter – Cornwall Campus event ‘Science In The Square’ (see for a short description my work blog ‘coastal pathogens‘). Briefly, the aim was to set up several small plastic trays and tanks with interesting local rock pool creatures and explain some fun facts to the general public (specifically kids). For instance, in one exhibit showing amongst others coralline algae, star ascidians and barnacles you had to guess which organisms were plant and which were animal (glossing over the fact that algae are not technically plants but OK). In another display (‘who’s the daddy’) we explained that it is the males in worm pipefish that are pregnant, not the females. In another display we explained that tunicates have larvae with a tail and spinal chord and that they are evolutionary more closely related to us than are for instance crabs, snails or starfish, something that is not very obvious when looking at the adults:

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The star ascidian Botryllus schlosseri. (For some pictures of the related colonial ascidian Botrylloides leachi, see a previous post.) We had a couple of small tanks filled with a variety of animals and seaweeds:

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A Giant goby Gobius cobitis, first time I saw one, almost 20 centimeters, quite impressive!

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