More Scummy Pools

As in Falmouth, the rock pools in Flushing are not looking that great at the moment. Lots of the Corallina has turned white/died (although the clumps in my tank are still their normal purple!). Of course, many species were still thriving, Grape pip weed Mastocarpus stellatus (top), Bunny ears Lomentaria articulata (bottom), new Thong weed Himanthalia elongata ‘buttons’ and a young blade of kelp along with some green Ulva:IMG_0977Among the seaweeds that were thriving was Slimy whip weed Chordaria flagelliformis (I am by no means a seaweed expert and I might be wrong about this, please comment if I am!) and also the beautiful Harpoon weed Asparagospis armata growing as an epiphyte on some darker coloured False eyelash weed. Harpoon weed is invasive and so a good candidate to do well int he aquarium (as most invasive species are quite opportunistic and not too finnicky). It died off in the tank before, but I decided to bring some home to try again now I have a chiller.IMG_0964

IMG_0970Another tangling invasive species: Bonnemaison’s hook weed Bonnemaisonia hamifera (a characteristic curved hook can be seen in the top-middle):IMG_1020Loads more seaweeds to be found but I will save those for another time. All kinds of tunicates pop up in spring, some of them pretty (see for instance here), some of them less so. For instance the invasive species, the Leathery sea squirt Styela clava and an out-of-focus photo of a second, large (>10 cm) species that did not get a lot of response on the NE Atlantic Tunicata FaceBook group. Aplidium nordmanni was offered, see here for a much smaller version of that species. Not a looker either in any case!IMG_1055

IMG_1030I brought my little aquarium net and found many juvenile (<1 cm) fish as well as Mysis shrimp. The fish look like gobies but it is hard to see. They were completely translucent and so you can see what this one just ate. I should take some bits of seaweed home to see what comes crawling and swimming out under a little USB microscope (quite easy to make little videos). It is hard to come up with decent images squatting and squinting on a slippery rock with a salt-encrusted mobile phone!

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Grevelingen

Two weekends ago I was back in The Netherlands for a short visit. The weather was great and we drove in my sisters camper van to the Brouwersdam, connecting the provinces of Zuid-Holland and Zeeland. This dam was built in 1971 and created the largest saltwater lake in Western Europe: the Grevelingen. We first stopped at the North Sea side of the dam though. This is spot is very popular with kite surfers, windsurfers and blokarters, with loads of people travel all the way from Germany even. Although great for sports, the Dutch coast is not the best place for a rock pool hunter (an bollenessor!) such as myself. The Brouwersdam provides hard substrate along an otherwise sandy coast, but there are no true rock pools and relatively few species of seaweed (mainly wracks and Ulva), some mussels and periwinkles and not much else:

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However, this seaweed looked interesting (I also found it in Bretagne recently), but I just cannot get it identified, any suggestions?

*edit* commenter Edwin reckons Chordaria flagelliformis and this was indeed the page in my Seaweeds of Britain and Ireland where I lingered longest, I think he is right!

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On the way back we stopped at the Grevelingen side. The Grevelingen is an unusual place: the water is salty, but there are no tides. There is only a very limited connection to the North Sea and so little water movement, which creates stratification and anoxic conditions in deeper waters, resulting in a  ‘dead zone’. In shallower water there is plenty of life though (check this site for instance). We waded on mud through very clear water to have a quick look (mud is not stirred up by any current and the lack of any inflowing rivers keep the water relatively nutrient poor en algae-free) . There were many Shore crabs about, and they were quite aggressive, trying to pinch my toes:

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I saw that Wireweed Sargassum muticum is very common here as well (see also this post and this post). These very large plants were colonized by fine red seaweeds and lots of Mysis shrimp were hiding underneath them:

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I also stopped by the natural history museum in Rotterdam that I have been a member of over half of my life. I noticed that in their permanent ‘Biodiversity’ exhibition that there was a shelf dedicated to seaweeds. Of course they deserve a place in such an exhibit, but I must admit that they look a whole lot more interesting in the sea than dried or in alcohol/formalin.

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