Chorda filum: Interesting sealife from the beach clean

September 23rd, 2019

During our beach clean on Sunday (22nd September) litterpickers found a number of rather strange cord-like objects in the strand line. The objects were generally translucent white, and resembled silicone rubber beading, of the type you might use to seal around the bath or kitchen sink. I brought a sample back home for closer investigation; it was 2.5mm in diameter, and held between tweezers, could be readily stretched by 20 of its resting length (a test section extended readily from 10 to 12cm), and recover apparently undamaged – so, rubber?

The mystery was quickly solved under the microscope, where the cellular structure of the material was evident. The samples were of Chorda filum (I call it sea-whip when I see it diving – for obvious reasons, see the photo below- but I think its common name is actually ‘sea lace’). I couldn’t find any reports of the histology of Chorda filum on the web, so I present a quick report into what might be the rubberiest plant on the planet below the photo!

Chorda filum or sea lace photographed off the south end of Gigha by Barry Kaye June 2018.
Above: Chorda filum living in shallow water of the south coast of Gigha: The fronds can be extended by 20% of their resting length – is this the rubberiest plant on the planet? (Photo BK)

Histology of Chorda filum

Generally seaweeds have very simple internal structures. Microscopy might reveal a gelatinous/slimy outer layer secreted by an organised skin or dermis, but there is rarely much internal structure to speak of. Seaweeds don’t need to transport water and salts from roots to leaves, as they are continually bathed in seawater, they can rely on diffusion for most transport requirements, so generally they lack the complex vasculature we see in higher plants.

Chorda filum, however, shows a very clever internal architecture; a central lumen stretches up the centre of the entire filament that constitutes the plant’s body. The lumen is surrounded by four or five layers of large box-like cells. These cells are at an angle to the axis of the filament – so they coil like a spring down the plant. This almost certainly contributes to the plants amazing elasticity, though I would not be surprised if there were not further mechanisms at the molecular level.

A thick transverse section through the stem to show the pitch of the box cells.

The box-like cells showed no internal structure in the sample I had from the strand line, but in places there was evidence of a further layer of cone-like cells attached by their apex to the outside of the tube of box-cells. These cells had clear chloroplasts in the wider end, suggesting that photosynthetic activity had been an important role in these cells while the plant was alive. I confess that I don’t understand why these cells are only attached at their apices, but this again might be to allow movement required as the plant is stretched and relaxes as each wave passes over it.

Longitudinal section showing the oddly shaped surface cells with narrow attachments to the main plant, and chloroplasts packed into the wider outermost part of the cell.

In conclusion; many seaweeds live in extreme environments. Chorda filum seems to have evolved a particularly interesting way of coping with the mechanical stresses of wave motion, and this may be one of the factors that permit it to colonise seabeds that lack good points of anchorage.

By Barry Kaye

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Morecambe Kite Festival 2019

July 3rd, 2019
Setting up the Lancashire MCS tent.
Setting up the Lancashire MCS tent.

After a year’s absence, it was good to be able to attend the Kite Festival at Morecambe again this year. Our ‘new’ gazebo had its first outing – and proved to be very successful, bringing us a bit closer to the people moving along the prom viewing the kites!

There was quite a lot of interest in our stand, and we are greteful to everyone who came to chat to us, as well as a number of donations. The local area group made £26.80 from donations, and sales of pin badges raised £42 for National MCS.

WW2 Dakota over-flying the Morecambe Kite Festival, June 2019.

Saturday, coincided with Armed Forces Day, so we were treated to a Dakota fly over and parachutists! Sunday was more difficult, with high winds causing us to close down a little early for fear of loosing our gazebo!

While the amounts of money raised are small, as long as we can break even, events like these allow us to ‘spread the word’ about quite how special the marine life around the UK is, and how much it deserves our protection. On this score, it was great to see how many younger visitors were interested in our marine life, and clued up as to some of the threats it faces…

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Betty Green

May 3rd, 2019

It is my sad duty to report that Betty Green has died. Betty and her husband Gil were great supporters of the group since its inception, and keen divers into their seventies! Betty’s love for, and understanding of, marine life was outstanding, and a great inspiration to all of us blessed to have known her.

I know that many of us hold fond memories of her, diving, or on shore walks. The photograph (by Chrissy Ryan) is on one of our trips to Lochaline. She will be missed..

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Loch Sunart and the Isle of Gigha

November 20th, 2018

Photo of a flame shell in Loch Sunart by Gordon Fletcher.
A big thanks to everyone who came along to our meeting, ‘Loch Sunart and the Isle of Gigha’ on the 14th November, which looked at the life in two very different post-glacial marine-scapes. Gordon did an excellent job exploring some of the fascinating life in Loch Sunart, which included flame shells (photo. above by Gordon Fletcher) and hard corals.

The life around Gigha might be described as prosaic – almost terrestrial in that is is dominated by large marine plants (though this is unusual for a marine ecosystem!). It did, however, open up a brief discussion about invasive species, led by observations of wireweed (Sargassum muticum) and Codium (tomentosum/fragilis). The problem with introduced species is that they are extremely difficult to remove once established, and the process of removal may be damaging to many other species in the area. For Codium, studies suggest that our native species are not being overwhelmed. Wireweed is hard to ignore, being a large spreading kelp species, but is also being colonised by local wildlife; so while it clearly competes with native species, it also presents opportunities for local wildlife. The final picture, I felt, was of quite a healthy mix of marine plant and animal species around the island.

You can read a more scientifically literate argument for considering invasives as a potentially valuable part of the ecological mix by Martin Schlaepfer in PLOS Biology – see ‘On the important of monitoring and valuing all forms of biodiversity‘.

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Nov 8: Meeting Cancellation

November 8th, 2017

Sorry, Marine Life in Morecambe Bay has had to be cancelled due to a double booking.

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Congratulations Betty!

May 31st, 2016

We are very pleased to report that Betty Green, a long time supporter of the group, has been awarded the The Wildlife Trusts’ Marsh Volunteer Award in recognition of her outstanding and demonstrable contributions to marine conservation. I cannot think of a person more deserving of this award!
Further details: Volunteer marine conservationist wins prestigious award

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Sponging a living

March 4th, 2016

Micrograph of the bryozoan Flustra

The Bay is home to a vast army of locals, who have survived and adapted to a landscape that appears at first glance to be empty… At our talks on the 10th February we investigated the most overlooked creatures of the Bay. The couch-potatoes. These are animals that, having found a place suitable to put down roots, have stopped there for the rest of their lives. They rely on the tides of the Bay to bring food to their waiting mouths.

The ecosystem of the Bay is driven by phytoplankton blooms, which are at their most extensive in Spring and Autumn. For the rest of the year plant life is comparatively scarce. In this environment our ‘couch potatoes’ play a vital role; every bacterium, every gram of poop, anything that can be recycled is brought back into the food chain. Despite their sedentary nature, these filter feeders are an essential part of life in the Bay.

This intensive re-use of all things organic has, unfortunately, an unexpected side effect. Organic toxins, such as PCBs (banned in the seventies) are held within the marine food web, and are responsible even today for the deaths of top marine predators, such as dolphins and killer whales (See for example: BBC report by Rebecca Morelle).

This sobering fact leads us some way towards our last talk of the Winter series in the Gregson – ‘Human Impact on the Bay’ on Wednesday 9th March. At this meeting we will look at a couple of the ways we impact the life of the Bay, through Fisheries and litter.

More information: Human impact on the bay PDF 77kB

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Roa Shore Walk 1st August

August 1st, 2015

I will be trying to be there for 6pm at the latest. Weather forecast is fine, but the temperature is not that thrilling for August so bring plenty of layers (at least one more than you think you will need!) as the shore is exposed to whatever wind is blowing at the time. The shore here can be muddy in places so bring clothes and footwear that you don’t mind getting mucky.

I’m looking forward to seeing the shore here for the first time since the swim last year. You may be surprised at what can be seen.

Lewis

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Morecambe Bay Kite Festival

July 5th, 2015

Kathy manning the stand at the Kite Festival.

The MCS had a stall at the Catch The Wind Kite Festival in Morecambe for the first time this year. The event had good weather, and there were a lot of people passing through, listening to music, or admiring the kites. We had quite a few people drop in on the stall, and I was pleased to see that many of the kites were marine themed, including an octopus and a pair of blue whales!

We are very grateful to the event organisers MoreMusic for providing us with space at this event, and to Kathy for enthusiastically manning our stand!

Red herring pennants flying at Kite Festival 2015

Above: Red (green and blue) herrings flying above the promenade at Morecambe during the kite festival, June 2015.

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Swimming success!

September 23rd, 2014

Roa Island Charity Swim 2014

Above: A photo taken at the Roa Island Yacht club just before the swim on the 21st September 2014 (click for larger version).

On the 17th August we were unable to swim due to bad weather (see post), and we were worried when we arrived on the 21st that we would be unable to get away because of building work on the jetty, which meant that our intended access to the beach was blocked! Thankfully Roa Island Boating Club came to our rescue, allowing us to set off from their slip. One of our swimmers also started from the yacht club, extending the swim to just short of two miles, the others took a lift on the support boats and left as intended from close to the Lifeboat slip, and everyone made it to the Piel Island slipway without mishap.

Unlike our attempt in August, the weather was perfect, warm, with clear skies and almost mirror flat water. The visibility was also excellent – we could see the bottom without being able to reach touch it from the surface! A very pleasant day out for everyone, and a big thank you again to boat crews who patiently looked after the swimmers!

We have currently raised £182 for National MCS – and you can still sponsor us through our ‘JustGiving site: justgiving.com/lancashiremcs/

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