Colour Underwater

September 2nd, 2019

The current storms indicate that summer is passing into autumn, and at Lancashire MCS we are starting to think about our winter lectures; which we hope will bring some interest into the darker months for you! Each year those of us on the committee dive deep into our store of knowledge to bring some element of the underwater world to life…

A number of years ago the subject of underwater colour was brought up, and I had thought this would be an interesting subject (though I did not know enough about it to present a talk;-) Over the years since then I have been gathering some relevant publications, and thought that perhaps this year I would try to bring them together.

The subject rather quickly expanded, as considerations of physics (transmission of light underwater), incidental colour (plants cannot help but be green – though seaweeds often are not!) and behaviour (how animals manipulate colour for communication and camouflage) all have an important part to play. When we look at how organisms produce colour, we get a glimpse into deep-time; the genes for green fluorescent protein (or their analogues) are present in all metazoans, suggesting colour may have been important to the Ediacaran biota 540 MYA.

Is red a colour?

Our eyes have adapted to life above water, but reds and oranges are strongly absorbed in seawater, leaving a monochromatic green-blue world. A lot of sea life is red, however, and some deep sea fish generate red light. We might, therefore, suggest that the colour red is significant even if it is only visible up close: At distance red light is absorbed, so anything red appears grey or black. If you only want to advertise locally, and don’t want to attract the attention of the big fish lurking in the gloom, red might be the most important colour!

Two photographs of brittlestars on kelp. the main image is taken from 5m in natural light, and they appear monochrome. The inset is taken at a distance of 30cm with a white strobe.
Two photographs of brittlestars on kelp. the main image is taken at a distance of 5m, and they appear monochrome. The inset below is taken at a distance of 30cm. To the best of my knowledge the colours displayed do not have any importance for the brittlestars concerned.

A comparison with other land animals suggests that colour perception in different species is likely to be very different to our own. Indeed, when age, visual defects, ill-health and genetics are taken into account, I might argue that colour is a personal experience, with even crude descriptions of ‘blue’ or ‘yellow’ meaning quite different things to each of us. (Web design in my day job, and it is quite important to ensure that text/background colour combinations are likely to be legible to readers!)

When we look at marine life, we see species with true colour perception ‘superpowers’. The most studied of these is that of the mantis shrimp – with twenty visual receptor types – twelve for colour (we have three), six for polarisation (we cannot detect this at all) and two for luminance (we have one). This suggests that the oceans are far from monochromatic, and there is hope for my talk…

See Unconventional colour vision by Justin Marshall and Kentaro Arikawa in Current Biology 24.24 (2014), R1150-R1154, for a primer in colour vision, and animal superpowers!

Barry Kaye

We are currently finalising our winter programme of lectures, and hope to have some external speakers this year alongside the ‘old guard’. please join us if you can – our Newsletter will keep you up-to-date.

Posted in Marine science update, MCS talks, Science

Risk and reward – the Roa Island shore walk 2019

September 2nd, 2019
Sand mason worms against the sunset at Roa, August 31 2019. By Barry

The drive up to Roa on Saturday was not very promising, with periods of torrential rain it was no surprise that only a few made the effort… In the event, however, other than a strong wind, the evening was very pleasant. We spent the first little while, however, spelling one of the lifeboat crew watching some kayakers to make sure they reached Piel Island safely!

Due to the wind we spent a little more time than usual to the West of the lifeboat jetty. The mud flats here are the home of a large number of sand mason worms (pictured above), and scattered with common starfish, which have been stranded by the tide as they hunt for cockles in the mud. Starfish have a hydrostatic skeleton, so are completely incapacitated in the absence of water. It is clear from the sad, deflated bodies, that a few do not survive exposure, but for many the chance of a meal must be worth the risk…

The visit also allowed me to take a plankton sample, which looks very different to the one I took on the dive in July, when there were no phytoplankton, and few zooplankton. The rougher weather recently may have helped spur some activity, as the sample from Saturday had high concentrations of phytoplankton, and lots of zooplankton and larvae, to recolonise the Bay. A few weeks can make a massive difference!

Barry Kaye

Posted in Marine science update, Shore walks

Review of Beach Cleans at Half Moon Bay

August 11th, 2019

Regular beach cleaners with our local group at Half Moon Bay, Heysham will know that we always take a survey of the litter collected and this information is put into a database held by MCS. We thought it would be interesting for people to see the attached graphs which show some of the changes in litter at HMB since 1998.

The main types of rubbish seen on the beach in 1998
The main types of rubbish seen on the beach in 1998
And those in 2018 – note the decline in santiary waste, due to improved water treatment, and changes in attitudes to flushing stuff down the loo… The increase in dog faeces left on the beach is less welcome.

Although this data may not be very exact it does show some encouraging changes for example items described under “sanitary” have reduced. Perhaps the “don’t flush” campaigns are working?

Plastic bag numbers have come down, though the amount of plastic in general has increased although oddly, glass has increased from 72% to 76% of the total rubbish on the beach.

Graph showing litter collected by effort.
Graph showing number of volunteers (red), number of items of litter collected per 10m of beach (blue) and total number of plastic bags collected (yellow) per year between 1998 and 2019 (note we have two more beach cleans planned in 2019!).

The local MCS group doubled the survey area at HMB in April 2018 but the amount of litter collected has not increased which is very encouraging. Although sometimes our volunteers are a bit disappointed that there isn’t as much to do!

MCS value the data we submit and believe it to be important for their monitoring purposes. They have asked us to continue to beach clean and survey at HMB.

So, we still need your support and really appreciate everyone giving their time and efforts. Of course you can beach clean/litter pick anytime, anywhere so why not carry out a 2 minute litter pick nearer home?

Kathy McAdam

Posted in Beach Clean, litter

Roa dive July 2019

July 29th, 2019
Scorpion fish hiding on the bottom at Roa, 26 July 2019, by Lewis Bambury.
The scorpion fish Taurulus bubais (photo by Lewis) waiting for something tasty to swim by (thankfully we are a little too big for it).

After a string of possible dates this year that we were unable to get in at Roa Island we finally managed a dive on Friday (we had to bring it forward a day to miss the worst of the weather). It was well worth the effort. Visibility was only 2 to 3 metres at best but that is plenty to search the reef for interesting macro life. Our species list – which for invertebrate species goes back to 1968 – grew by at least 2 new species. First to be found were several Goldsinny (Ctenolabrus rupestris), unusual not just as a first for that species, but the first species of wrasse to appear on the list.

Goldsinny, photo at Roa by Barry Kaye, July 2019
Goldsinny, photo at Roa by Barry, July 2019

The next was a nudibranch (that’s a fancy name for a sea slug) called Jorunna tomentosa (pictured below) – it doesn’t have an English name. Both are common species around the coasts of the UK, so of course may have been here all the time, but this is the first time we have them on record here.

The nudibranch 'Jorunna tomentosa' photod by Lewis Bambury at Roa, July 2019
Jorunna tomentosa feeding on one of the sponges (possibly Haliclona sp.) common at Roa. Photo by Lewis Bambury, July 2019

There are many predators in the marine ecosystem and animals have a variety of strategies to help them find food, and avoid being eaten. The Long-spined Scorpionfish is a master of disguise – hiding in plain site by blending its skin colour in with its background; if a crab or small fish comes too close they will be grabbed at lightening speed, predators large enough to tackle it will need sharp eyes to see it, and if they do this fish has a back-up plan – the eponymous long spine on its gill cover, just visible in this picture.

Perhaps the most suprising thing about the dive was the water temperature – depending in depth it ranged from 18ºC to 20ºC. I don’t think that I’ve dived in water that warm either at Roa Island or anywhere else around the Irish Sea. Unfortunately I can’t check my dive logs after a computer glitch trashed them a couple of years ago.

Thanks to Philip and Rebecca for providing shore cover!

Lewis Bambury, July 2019.

Posted in dive trips, Shore walks

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…

Posted in Uncategorized

Summer beach clean 2019

July 2nd, 2019
Photo at the end of the beach clean in June, by Ian Croucher.

A big thank you to everyone who turned out for the beach clean at Half Moon bay on the 5th June – a decidedly un-summery evening. The photo is by Ian Croucher, having his first taste of a beach clean, and looking to set up or join similar events with colleagues from work on the railways, so we wish him all the best!

Again the beach was relatively clean – which is good news, though we are seeing more wet-wipes than has been the case in the past. Again a quick reminder to anyone who has not got the message – don’t flush wet wipes. Despite what it says on the packet, they don’t belong down the loo.

Posted in Beach Clean, litter

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..

Posted in Uncategorized

Destroyers!

March 1st, 2019

Photographs of Orkney, sea slug and diving the High Seas Fleet.
Above top: An Orkney seascape (with defensive positions) by Lewis. Below the seaslug Coryphella by Gordon, and a diver on one of the wrecks of the German High Seas Fleet by Lewis.

Two talks about two very different types of destroyer – Lewis Bambury will talk about Orkney, including a look at how events from 100 years ago gave the islands some of the best diving in the world. Gordon Fletcher will look at the colourful world of sea slugs, giving you the chance to hear about the feeding habits of these predatory carnivores, their unusual sex lives, and the extraordinary defence mechanisms they utilise to avoid being eaten by larger predators!

These talks will be followed by the local group AGM.

Wednesday, 13 March: 19:30 – 21:00 at the Gregson Centre, 33 – 35 Moor Gate, Lancaster LA1 3PY.
Admission £3.00, everybody welcome!

Posted in MCS talks, Science

Invisible World: marine primary production

February 5th, 2019

Man and animals are in reality vehicles and conduits of food, tombs of animals, hostels of Death, coverings that consume, deriving life by the death of others. Leonardo da Vinci

Plants are rather different – quietly converting sunlight into the food we need to survive; the shepherd with his grazing flock is the subject of a painting, the meadow, a beaucolic backdrop. In the worlds oceans, however, the plants that form the meadow are microscopic – completely invisible to the naked eye. Indeed, for most of the 20th century, the main players remained elusive even to the best optical microscopes!

Over the last decade or so satellite imagery, coupled to unmanned submersibles, have begun to reveal the true extent of marine ‘plant life’. We find a complex, dynamic pattern of blooms, and rapid disappearances keyed to the seasons, currents and climate. Alongside this, genetics has begun to unravel the complexities of the interrelationships between the different groups of marine plants – and animals…

Join us on Wednesday 13th February between⋅19:30 and 21:00 at the Gregson Centre, 33 – 35 Moor Gate, Lancaster LA1 3PY for a personal look at some of the recent research in this area.
Admission £3.00, everybody welcome!

Posted in Events, Marine science update, MCS talks, Science

Dark and dull? Underwater wildlife photography in British waters

November 27th, 2018

Tunicates and worms by Barry Kaye

At our next meeting, members of the group will take personal views on the subject of photography around UK coastline. This will include a look at the photographic equipment they use, and the challenges they face in getting a ‘good’ photograph. Main speakers: Gordon Fletcher (film), Lewis Bambury (digital), Jo Kaye (macro).

Dark and dull? Underwater wildlife photography in British waters (PDF 117kB)
Wednesday, 12th December, 19:30 – 21:00 at the Gregson Centre, 33 – 35 Moor Gate, Lancaster LA1 3PY.
Admission £3.00, everybody welcome!

Please note, we do not have a meeting in January 2019, our first meeting of the New Year wil be in February, the remainder of our winter lecture programme is available in the PDF linked below:

MCS winter lectures 2018 (PDF format 82kB)

Posted in Marine science update, MCS talks