30 May 2017

Half-term Tuesday 30 May 2017; Runswick Bay today.

A great day for rockpooling, low tide is at 1427. Head beyond the sand towards Kettleness and you come across an area of flat, hard shale with lots of rockpools:
 Check out how the species of seaweed change from the top of the beach to the waterline; the dominant green algae (Ulva lactuca) is replaced by saw wrack (Fucus serratus). At this time of year you'll see lots of anemones like this:

The tentacles have stinging cells (nematocysts) for paralysing small creatures which they then drag into the mouth. If they're surprised anemones withdraw the tentacles and hunker down to look like a red blob.

If your kids are paddling at low tide make sure they have something on their feet; this is where weeverfish lurk. They hide in the sand with venomous spines sticking up and a sting in the foot is painful. The remedy is to soak the sting in hot water. If you see anyone in difficulyy in the sea, on the beach or cliffs dial 999 and ask for the Coastguard.

29 May 2017

Monday 29 May; Bank holiday Runswick bulletin.

Weather: misty, drizzly, slight breeze not a good beach day.

Tides: low water 1335 (0.8m), high water 19.42 (5.6m).

Natural history of Runswick Bay of the day:

This blobule is a ctenophore or comb jelly or sea gooseberry. While not clear on this pic, it has rows of hair like cells called cilia that run vertically along its body that beat the water to propel the creature along. They are washing up in large numbers on the beach night now and are harmless to handle but die and decompose very quickly if kept out of water for any length of time.

7 Apr 2017

Visiting Runswick Bay this Easter

High tides for the first week of the Easter Holidays:
Friday 7th April 1425
Saturday 8th April 0303 and 1517
Sunday 9th April 0348 and 1600
Monday 10th April 0427 and 1639
Tuesday 11th April 0502 and 1715
Wednesday 12 April 0535 and 1749
Thursday 13th April 0607 and 1823

Those times are great for families wanting to spend the day on the beach, but be careful especially on Tuesday, Wednesday and Thursday when the spring tides mean that the tide will rise quickly.

Also please don't go too close to the cliffs; there has been one big cliff fall towards Kettleness:

There is more at risk of coming down here and please don't go rooting in the rockfall for fossils; the fossils from this kind of shale are so flattened and mineralized they can't be extracted from the rock. There have been several minor ones along the length of the cliffs. The cliff around the Hob Holes (the four caves) are also heavily cracked, at risk of collapse and should be avoided. Don't let you kids go in the caves no matter how tempting they seem:

Other than that, enjoy Easter on Runswick Beach. We've been having some interesting things wash up, like this colourful sea urchin (photo by Elke McGrath):

And if you do see anyone in danger on the cliffs, the beach or in the sea call 999 and ask for the Coastguard as well as any other emergency services. If you can't get a phone signal the staff at Sandside Cafe will contact the emergency services.

8 Dec 2016

One that got away; Jurassic cycads.

The big cliffs that dominate Runswick are Jurassic in origin. The crumbly mudstone and shale is lower Jurassic (201 - 174 million years ago) which is capped by mid Jurassic sandstone. Most of the fossils you'll find in Runswick's rocks are the stuff of a warm Jurassic sea; ammonites, belemnites, Gryphaea and bottow-drwlling bivalves. There is the occasional big, exciting find: there is a juvenile Icthyosaur skull in Whitby Museum, which has an excellent collection of local fossils. Visit if you haven't.

The cliffs to the north of Runswick are Wrack Hills; they're a site of special scientific interest which means you can't collect fossils from there; they were home a fine seam of Jurassic plant fossils. Above is one that fell from the cliffs in a block of sandstone. It may be only one left; in 1980, 1981, 1982 and 1984 Natural History Museum staff visited and excavated the cliffs, removing an enormous number of scientifically significant fossil plants without permission from the landowner.

Here's one that got away; looks like Ptillophylum pecten.

Reference: Palaeobotany and petrology of a Middle Jurassic ironstone bed at Wrack Hills, North Yorkshire. Proceedings of the Yorkshire Geological Society, 45, 277-292.

25 Aug 2016

Weever fish; stings and treatment.

If you are visiting Runswick Bay or any other sandy UK beach you need to know about this; the Weever fish, a member of the family Trachinidae:
Weevers are small fish that like to hide in the sand around the low tide line. The spiky fin just behind the head has spines that, if you step on them, will deliver a venomous sting. This is rare; every day this summer hundreds of thousand of feet will have splashed through warm, sandy shallows without incident but today while I was on the beach one young man stepped on a Weever.

The sting is painful, it is not fatal and it is very easily treated; PUT THE SITE OF THE STING IN WATER AS HOT AS THE CASUALTY CAN BEAR. The pain will diminish almost immediately, but keep the treatment going for around 15 minutes. Watch out for shock; Runswick Bay's Weever victim was fortunate to be treated by an experienced first aid instructor from Barefoot Kayak (which hires kayaks and paddleboards at Runswick during the summer holidays) who spotted the shivering and wrapped him in a thermal blanket.

Weever stings are rare, don't let fear of them stop you enjoying our lovely beaches. They are most common around spring tides in August; as a precaution don't paddle at the low tide line during spring tides and if you do wear shoes.

We didn't get to see the offending fish, but it was probably a Lesser Weever (Echiichthys vipera).

23 Jun 2016

Double-decker gastropods.

When all that crawling and slime-making just gets too much, hitch a ride on a limpet.
They're all at it...

22 Jun 2016

Runswick's naval mine (an unusual habitat).

Somewhere in the seaweed-covered rocks beyond the morass of stinkily-decaying seaweed there was rumoured to be a WW2 naval mine. Today I went on an expedition to find it, and on the far edge of the bit of the beach known as Jarvis' Landing Hole I stumbled across it:
The beach hereabouts is uncharacteristically rocky; I think this is the debris from when the village of Runswick (bar one house) and much of the cliff on which it was built slipped into the sea in 1682. The mine is probably WW2; it there are several small holes in its case which suggests it was sunk by gunfire; it's estimated there are 1.3 million tonnes of unexploded WW2 munitions on the bed of the North Sea. It was now become a rather snug home for barnacles (lots of juveniles) and limpets.
Lots of limpets means food for whelks; this one's a bit out of focus, and has a necklace of juvenile limpets growing on its shell:
The mine's explosive filling is long gone, inside it's shaded and there is a permanent rock pool which is home to flustra, saw wrack, red algae, crabs and amphipods:
The mine is at the part of the beach where knotted wrack (Ascophyllum nodosum - seen here with lots of its parasitic red Polysiphonia lanosa):

  is replaced by saw wrack (Fucus serratus):
A stream that drains the rockpools further up the beach runs around the old mine; it provides a home for beadlet anemones and Pomatoceras triquiter.
And, wedged under the bottom of the mine, an ammonite counterpart, home to a topshell and a very well camouflaged chiton (it's at the ammonite's 12 o'clock):

24 May 2016

Rockpool residents; chitons, a poychaete and a hermit crab.

A trip to the beach with the youngest field assistant on a warm day; the tide was out and there were plenty of rockpools to explore on the sideritic bench between Runswick and Kettleness. The rockpools were warm; a tribute to the evolutionary fitness of the creatures that live there. They've become adapted to withstand wide ranges of salinity, temperature and dissolved oxygen levels. The youngest field assistant was bossing the sampling show:

We found a pair of chitons, one rather plain the other a crazy pink:
Does it become pink through grazing on the encrusting pink algae thereabouts or has the algae decided to use the carapace of this rather slow moving shellfish as a home?

We also found a polychaete worm. S/he had an impressive little tuft of antennae on the head.

Being in a bit of an interested-in-shellfish phase right now I took a pic of this one happily hunkered down surrounded by coraline and red algae:

It promptly sprouted legs, antennae and eyes, and marched off, a bit of 'no pictures!' in its hermit crabby manner.

An upended rock revealed an anemone amid a colony of Pomatoceras worms with some green seaweed (Ulva lactuca) trying to get established.

 The youngest field assistant wanted to poke his finger into the anemone's mouth. The rock was replaced, the anemone unpoked after a quick lesson about nematocysts.

19 May 2016

The evolution of Runswick's Mesozoic marine reptiles.

The mudstones and shales which make up the lower Jurassic portion of Runswick Bay's pre-history are the fossilized seabeds from a time when Runswick was under a shallow, warm equatorial sea. Fossil finds hereabouts show that the sea was heaving with ammonites and belemnites, the muddy seabed was a mass of shellfish; Gryphaea (oysters), Pecten (similar to scallops), Pseudomytiloides (like a flattened mussel) and Dacromyia (like a small cockle) to mention but a few. The Jurassic seas were also home to big creatures too; plesiosaurs (think Nessie, only real), icthyosaurs (dolphin-alikes), crocodiles and turtles. Obviously these large, swimming creatures had an evolutionary backstory and here it is, free to read in an open access scientific journal:

Ecomorphological diversifications of Mesozoic marine reptiles: the roles of ecological opportunity and extinction
We haven't yet found a complete Jurassic marine reptile specimen which could add to the work done by Mr. Stubbs and Mr. Benton, but hope it's only a matter of time. Thanks to them, their publishers and the internet for letting those of us who are interested learn a bit more about this kind of stuff. (And I know the paper is about Jurassic marine reptiles per se, but I'm only interested in Runswick Bay. Dead reptiles in other parts of the world can find their own damn blogger.)

17 May 2016

Apologies for the radio silence...

going to the beach sampling, collecting and measuring is hard when you're coughing like a romantic poet dying of consumption. The lurgi (for amateur epidemiologists amongst my readers the local GP said that this winter flu epidemic came late and was an absolute stinker - the worst he had seen in his 25 years of doctoring) seems to have passed so I'll be back on the beach and posting regularly.

In the meantime do occupy yourself with some entertaining reading: the North York Moors National Park blog is a good read, they're up to G in their A to Z of the park so if you're interested in the Gardens, Geology and Goths of the Moors, pop over and have a look.

Capturing our coast is a wonderful initiative. If you haven't yet, go, read and if you can spare the time get involved in this wonderful citizen science project. We're an island and we should know and care more about our coasts and seas.

And if you haven't discovered it yet, off you go to Richard Carter's Nature Writing flipboard.

Until the new posts start flowing, have a whalestone, a concretion from the cliff about 1.5 metres across:

28 Apr 2016

The May Dalesman is out!

This month it's all about shellfish and Vikings, after a day sampling rockpools on Runswick beach with this blog's youngest field assistant. £2.99 from all places civilized.

19 Apr 2016

Finally, a spring day with some of nice fossils. (Updated)

We did a quick safari to the beach to find the almost up tide up (this pic is 2 hours before high water), so little natural history to be done. So we had to content ourselves with a very quick rampage amongst the rocks to see what fossils we could find.

As it happened, not a bad haul:
Right to left:
1. A 2cm diameter ammonite, juvenile or adolescent Arnioceras semicostatum (the specimens in the field guides, which I assume to be adult are 4 cm across). Andy from Andy's Fossils contacted me in comments to suggest that this is actually Hilderocas bifrons (likely to be found in Runswick) rather than Arnioceras which is not) for which many thanks. He's probably right.

2. At the bottom is a Gryphaea, a fossil oyster which died c. 185 million years ago. I and my field assistants find lots of these but this one is in a shingle-smoothed block of dead, fossilized, smashed together molluscs. Probably the result of a mudslide sweeping these creatures from their muddy home into an anoxic (oxygen-deprived) basin (I've been swotting up on the Jurassic conditions hereabouts, thank you Mr. - soon to be Dr. - I hope - Johnson) which killed them en-masse.

3. Coral or a sponge. Jurassic, much smoothed so hard to identify.

4. Star of the show. I think you're looking at a fragment of mid-Jurassic plant, probably a cycad. We found this on the beach at the foot of some cliffs where we know cycads have been found before. The place is a Site of Special Scientific Interest so off limits to fossil collecting but not off limits to 'measuring a section*', which is what my smart wife (a natural science graduate from the University of Toronto) suggested we do. You see, the rock matrix a round the fossils isn't what you'd expect on our beach. Up the cliff we went, looking at the changing geology as we did. After much scrambling, hanging onto blades of glass, scrabbling dirt away from the underlying rock we hit rock similar to that encasing our beach fossil. A glance at our geology field guides at home and it was bang in the geological horizon for the Jurassic cycads.

* Measuring a section means you find a specimen at the foot of a cliff (or, if you're unlucky, mountain) and traipse up the thing looking at every stratum to see where the thing came from.

30 Mar 2016

Upper beach seaweed, early spring.

Green Ascophyllum nodosum (knotted wrack) in full reproductive swing; the spotted lighter sacs are the conceptacles, the seaweed's reproductive organs. The wispy red algae is Polysiphonia lanosa which lives as a hemiparasite on the Ascophyllum. 

The Bay yesterday was looking rather splendid:

It was an Easter holiday ramble of the beach with the youngest field assistant, but we found a couple of Gryphaea, extinct Jurassic oysters:
The right hand specimen has a small, almost complete Gryphaea on the left hand side, the rest is made up of smaller specimens. I've been reading a dissertation of the Jurassic geology of this area which talks about anoxic events; periods when the seabed became inundated with dexoygenated water, killing whatever creatures got in its way. When you see large numbers of fossils dead together, an influx of anoxic water or getting caught up in a mudslide might be the cause. Some Jurassic creatures found as fossils in Runswick beach thrived in low-oxygen conditions such as these Pseudomytilus dubius, bivalve molluscs. These ones are rather splendidly pyritized (coated in fool's gold) on the outside of a pyritic nodule.

17 Mar 2016

Runswick Bay sand through the microscope.

The blue is (I suspect) a microscopic piece of slag from the ironworks that was built on Lingrow undercliff to the north of the village in 1857, and collapsed in a cliff-fall a year later. Or it could be a fragment of a mussel (Mytilus edulis) shell.

9 Mar 2016

A chiton.

These molluscs are unusual in that instead of having one big shell (like limpets or whelks) their armour is made up of eight overlapping plates. Under this exciting exterior is the creature's greenstuff; mouth at the front, algae-scraping radula to drag food into the oesophagus, a stomach and a coiled bowel that makes and excretes pellets of digested algal biofilm residue. There are gills down each side, under the shells. One group is carnivorous, trapping prey under its shell before consuming it.

Someone, a scientist of heroic patience, has suggested that like limpets, chitons have a homing instinct. Their sensory organs protrude between the plates of the shell to tell the chiton (of which there are an estimated 750 living species) what is happening and are wonderfully named: aesthetes.

Chitons are mollucs, class polyplacophora. For a brief and intelligent introduction to these creatures, the UCMP page cannot be beaten.

8 Mar 2016

A quick beach walk for Fossil Friday on twitter.

With lots of people tweeting their favourite fossils last Friday I thought I'd do a quick beach walk and photograph everything I saw. The tide gave me 35 minutes. Here's what the mudstone cliffs gave me. First Runswick Bay when I started:
The first thing I saw was a heavily wrecked ammonite fragment.
That's better. Arnioceras semicostatum I think. 
Back to much-mangled ammonites.

A belemnite guard, end on (or transverse section, as they say in scientific circles).

 Hard to ID bivalve counterpart (centre left) maybe Pseudopecten equivalvis and three Nuculana ovum.

A couple of Dactyloceras commune. No fossil walk near Whitby would be complete without a Dact or two. 

No idea. All suggestions welcome.
Pleuromya, three Nuculana and a fragment of a belemnite guard.

Fragment of ammonite counterpart.

Very weathered ammonite, not much to identify it from but I'm having a stab at Oxynoticeras oxynotum.

Small, smashed and pyritized Pseudomytiloides.

An ammonite in a nodule.

Another ammonite in a nodule.

More ammonites; part and weathered counterpart.

Not another ammonite!

Four more bivalves.

And just when you thought you were done with ammonites, I found a fossil collector's midden. These guys didn't make someone's cut.

The tide was flooding fast, the Bay had clouded over by the time I left.