#13 Dabberlocks by Jane Pottas
Meet Jane Pottas, a phycologist from Whitby!
Jane is a professional phycologist living in Yorkshire. From a young age she spent many happy hours peering into rock pools, and it was this childhood fascination that led to her lifelong passion for intertidal ecology, specifically seaweeds. After teaching GCSE and A-level science, a family tragedy led her to reassess her priorities and with a reduced teaching commitment, she embarked on a self-funded PhD studying the ecology, morphology, and genetics of Fucus spiralis (spiral wrack). On completing her PhD, Jane lectured undergraduates and worked for the North York Moors National Park as an Education Activity Leader before accepting contracts working on the seaweed collection at the Natural History Museum, London - her idea of heaven! Later, she worked as a Field Assistant for the citizen science project Capturing Our Coast, as an occasional tutor with the Field Studies Council, and then as a tutor on a Science Access Course. As if she wasn’t busy enough, Jane was also Secretary of the British Phycological Society for nine years, and is the Seashore Recorder for Whitby Naturalists’ Club.
Jane’s chosen species is the brown seaweed Alaria esculenta. With a long list of common names including Bladderlocks, Dabberlocks, Edible Kelp, Honeyware, Wing Kelp, Tange, Murlins, and Stringy Kelp, this seaweed’s name translates literally as ‘edible wings’. Alaria esculenta is a widely distributed kelp generally growing in exposed places at low water in the shallow subtidal and in rock pools on the lower shore. It is unusual amongst the kelps in that it has a distinct midrib and unlike the other kelps which have thick leathery blades, A. esculenta is less robust and has thinner blades. Species in the genus Alaria are adapted to temperate-to-cold waters in the northern hemisphere. Alaria esculenta is restricted to the 16°C isotherm and is absent from the southern North Sea (south of the Flamborough Front) and beyond the English Channel to the south. There are estimated to be 12,000-15,000 species of seaweed in the world, with 650 species in Britain and Ireland. Amazingly, about 100 species can be found on a single shore. You can read more about this species on the NBN atlas, and find its distribution here.
Alaria esculenta (Dabberlocks) David Fenwick.
Especially interested in intertidal ecology, Jane visits the shores around her home town of Whitby throughout the year to record, collect, and photograph the species she finds. She is also in the process of collecting specimens for an algarium – a collection of pressed specimens – of seaweeds found on the coast of North Yorkshire for Whitby Museum. It was during her role databasing seaweeds at the Natural History Museum when a specimen of Dabberlocks came to her attention.
“Each of my contracts at the NHM included databasing specimens in the collection and whilst engaged in this one day I came across a large specimen of Alaria esculenta which had been collected by one Edward George in Whitby in June 1866. My interest was piqued - a specimen from home! This specimen, extending over ten herbarium sheets, turned out to be the largest in the NHM seaweed collection. Impressive.” NB. this is not the largest seaweed in the world – that honour goes to the giant kelp, Macrosystis pyrifera, which can grow to 65m and in length at a rate of 60cm a day).
Edward George was a respected amateur collector of mosses and later algae and holidayed in places where he could study and collect specimens. Born in Salisbury in 1830, he later lived and work in Forest Hill, London where he died in 1900. His collection of pressed specimens is now in the NHM which was where Jane came across them in 2011. Back in Whitby, Jane visited the library of the Whitby Literary and Philosophical Society to see if she could find any more information. It may seem strange today to see a list of visitors published in the local paper but on Saturday June 30th 1866, the Whitby Gazette recorded a Mr and Mrs George of London staying at 3 Royal Crescent, Whitby; the visit on which he collected this amazing specimen.
Alaris esculenta distribution, Yorkshire.
Despite having lived in Whitby for over 40 years and a regular visitor to its shore, Jane had never seen a specimen as large or as in good condition as the one at the NHM. Because Dabberlocks is less robust than other kelps, it soon degrades once detached and the blades disintegrate, so a large, virtually intact specimen was a mystery to Jane. Edward George would not have dived for specimens, so was he just extremely lucky to find an intact specimen? This is still a mystery!
Edward George’s Alaria esculenta specimen at the NHM.
Climate change, including rising sea surface temperature, is an important factor influencing coastal seaweed communities and sea surface temperatures in the northeast Atlantic have been warming at a rate of 0.3-0.4 degrees Celsius per decade over the last 40 years. Dabberlocks has been proposed as an indicator species for monitoring the effects of climate change in Britain and Ireland with the prediction that the southern limit of its range will move north as sea surface temperatures rise. Without data about the distribution and abundance of species, however, it is not possible to demonstrate the effect of climate change on particular species or on biodiversity. Long term data sets would be the ideal resource. The collection of seaweeds in Whitby, including Alaria esculenta, by Edward George in 1866, and Jane’s own collection of seaweed species along this coast made over the past 10 years are but snapshots in time. Herbaria and algaria specimens indicate what was growing where and when, but they are generally a haphazard collection made without a particular reason in mind. This should be adequate justification for keeping them (some collections have been threatened with destruction) for they show no significant collecting bias, but gaps in the collections must be treated with caution – absence of evidence is not evidence of absence. Collections of pressed seaweeds in museums, universities and private collections all over the country (and indeed the world) can provide baseline data but we need to know about present day distributions and collecting must continue in order to monitor what is where and when.
Monitoring
Jane would urge anyone spending time on the shores of the Yorkshire coast to look out for attached and detached specimens to press and incorporate in an existing collection or to start their own algarium. Who knows what will intrigue and mystify future generations, or what questions such specimens will hold the answer to in future! The British Phycological Society runs a nationwide recording scheme which accepts records of seaweeds and algae. Local naturalists’ groups in the region including Whitby also accept local records of seaweeds.
Further information and acknowledgements
NEYEDC would like to thank Jane for her time and expertise in helping to create this blog. If you’d be interested in contributing a piece for the series, contact Lucy at lucy.baldwin@neyedc.co.uk. To find out more about biological recording, see the Naturalists page on our website.
References:
Mieszkowska N, Kendall M., Hawkins SJ, et al. (2006) Changes in the Range of Some Common Rocky Shore Species in Britain – A Response to Climate Change? Hydrobiologia 555:241–251
Yesson C, Bush LE, Davies AJ, Maggs CA, Brodie J (2015) Large brown seaweeds of the British Isles: evidence of changes in abundance over four decades. Estuar Coast Shelf S 155:167–175