The City Nature challenge took place between 25th to the 28th of April this year, this was a Global challenge to record as many species in as many places as possible. As the dates coincided with a plankton sample, I decided to try and submit some species from this to the Lancashire record.

On land, Spring is really getting into its stride by late April, in the Wyre Estuary, however, Spring has been and gone! The date fell into a relatively quiet period between the big Spring bloom of Odontella regia (which this year coincided with a bloom in Asterionella glacialis due to the exceptionally sunny weather in March), and the arrival of the Summer species.

Above: Phase contrast micrograph of Cerataulina pelagica, 25th April 2025, by BK.

Though the Spring species were still present in very low numbers, most of the phytoplankton were Ceratauline pelagica, shown in the image above, which has such a thin silicate frustule that it normally breaks when sampled by netting, which can lead to gross underestimation of its numbers.

Numbers of dinoflagellates were higher than is common in the estuary; most common was Tripos fusus (the accepted names for the Ceratiaceae as a family have all changed, previously I would have recorded this as Ceratium fusus), but I also managed a photo of a very nice specimen of Tripos macroceros, which is rather less common in the estuary all together, and is shown in the micrograph below:

Above: Phase contrast micrograph of Tripos macroceros, with a central stem and two long, sweeping horns, there are a number of cells of Cerataulina pelagica to the left of the dinoflagellate.

Along with a few stragglers from the Spring bloom, I also saw a few species that will likely play a more important role in the plankton community later in the year. The most common were Guinardia delicatula and G. flaccida, but I also had my first sighting of Stephanopyxis turris (one of my favourites to try an photograph – unfortunately I did not get a good micrograph of the single individual I spotted on this occasion), and a couple of cells of Eucampia zodiacus.

In all, members of the public submitted 4295 observations to the Lancashire records, which included 1028 species! The City Nature Challenge is recorded in iNaturalist at: https://www.inaturalist.org/projects/city-nature-challenge-2025-lancashire-uk.

If you would like to know more about plankton – with an emphasis on our studies in the Wyre Esuary – we have a one day course planned on Thursday 12th June 2025, which will cover the basics of microscopy and photomicroscopy, as well as an introduction to identifying local phyto- and zoo- plankton. Contact me by 1st June if you would like more information!

Barry Kaye, 9th May 2025

Wednesday 9th April 19:30: by Mark Woombs and Barry Kaye PLUS group AGM by Kathy MacAdam.

Last year I showed a probable relationship between plankton blooms in the Wyre Estuary and the number of hours of sunlight, and I speculated that better weather in Spring this year might see a repeat of the Odontella bloom that characterised the early parts of 2022 and 2023, but was completely absent in 2024. We have certainly had good weather this Spring, so we will see how this has impacted our local phytoplankton in this talk!

Part of my research has been looking at local Met Office records, to quantify what weather we should expect at different times of the year, and how much this varies. This turned up some interesting results – if you thought that the best of the weather was now in the Spring, and our Summers are not as good as they were in your childhood, then, (depending on how old you are!) there might be some truth in this:

Above: Average hours of sunlight per month between 1908 and 2025, compared with 2000-2025 from data published by the Met Office for Bradford. The data show that there is more sun in Spring, but less in our traditional Summer. The graphs overlay a micrograph of a cell of the phytoplankton Odontella regia, which may be impacted by the changes.

Above: Photomicrograph of Porcellidium sp. by Mark Woombs

The meeting will start with a brief AGM hosted by Kathy. This will be followed by two short talks rounding up plankton studies in the Wyre Estuary over the last 12 months. Mark will look at how to get their ‘best side’ when photographing zooplankton, while I will attempt to shed more light on the question of whether phytoplankton respond to the weather (and how to measure these changes).

At Lancaster Maritime Museum, Custom House, St George’s Quay, Lancaster, LA1 1RB
£4 donation requested to Lancashire MCS
Everybody Welcome!

Disappearing diatoms and Sex in Copepods – Knott End Plankton round up, Spring 2024
Talks by Mark Woombs and Barry Kaye (Lancashire MCS) on Wednesday 8^th May 2024 at 19:30 at Lancaster Maritime museum.

We are now into our third year studying the plankton at Knott End, and this year we are witness to a failure of the Spring phytoplankton bloom due to poor weather. Perhaps for the same reason, the copepod breeding season has been pushed back two months; though zooplankton numbers as a whole seem to be resilient… Join us to find out more!

If you would liek to check out some of the data from our plankton surveys at Knott End for yourself, there is a graphical interface on our website. This allows you to select plankton by groups or individual species, and follow how their populations have changed over the last eighteen months.

POSTER: Plankton, Spring 2024 (172kB PDF)

Wednesday 14^th June at 19:30 at Lancaster Maritime Museum

Above: Phase contrast micrograph of phytoplankton at Knott End, April 2023. Species depicted come from number of families include Asterionellopsis, Stephanopyxis, Chaetocerus, Pseudo-nitzschia, Odontella and Ditylum, indicating just some of the diversity on our doorstep! Photomicrograph Barry Kaye.

Phytoplankton are the smallest plants on the planet, yet vital to all life. While they drift at the mercy of ocean currents, they are very sensitive to their environment, and are capable of explosive growth when they encounter the right conditions. In this talk we will look at the phytoplankton sampled at Knott End over the last 18 months, to get a glimpse of its diversity, and begin to understand how it changes over time.

Join us on Wednesday 14th June 2023 at 19:30 at Lancaster Maritime Museum to find out more.

A talk by Mark Woombs, looking at some of the zooplankton in Morecambe Bay.

Above: Planktonic worm larvae (top left, shows micrographs at two stages of development) eventually settle to form reefs up to 2m tall, like this one close to Conger Rock, Morecambe (with Heysham power station in the background). Photos Mark Woombs.

Is it possible that a microscopic worm can develop into this extensive reef close to the town of Morecambe, via a trip around the Irish sea? Come along to our next MCS meeting and find out about this, and many other amazing happenings in Morecambe Bay!

To find out more, join us at the Lancaster Maritime Museum on Wednesday 10th May 2023 at 19:30 for:

Mark’s Mini Monsters – Zooplankton of Morecambe Bay

by Mark Woombs (Lancashire MCS)

One of this year’s projects has been to carry out regular plankton samples in the Wyre estuary at the Knott End slipway in conjunction with the Wyre Rivers Trust. Jean has worked up some of Mark’s super photos from the surveys, and put them as pin-ups for the coming 12 months in our calendar. Armed with this, next time you go in the sea, you will know who you are swimming with!

Calendars are on sale at £8 each, proceeds to Lancashire MCS and WRT. Collect at our meetings in December or January. Please note that numbers are limited!

I am not as up on zooplankton, but thought I should follow up my earlier post on phytoplankton dynamics in the earlier part of the year with something to indicate that the zooplankton are not (too) boring! For this article I have chosen the sea gooseberry Pleurobrachia pileus which, at about 2cm in diameter, is a member of the zooplankton which is large enough to be seen – though difficult to spot in the water as it is transparent… You can often find individuals stranded as the tide goes out, but their appearance on the beach as small lumps of jelly does not do justice to them underwater. In their element they are propelled by rows of modified cillia called ‘ctenes’ – you can see eight rows of ctenes, slightly inset into the otherwise oval body of the animal in the photo above. These ctenes can refract light to give bright and continuously changing coloured displays underwater…

The population of Pleurobrachia pileus reached a peak in the Wyre estuary in early June, when small examples of Beroe cucumis first appeared in the fortnightly samples. Initially the Beroe were only a few millimeters long – very much smaller than the Pleurobrachia. Despite this they latch on to their very much larger prey, and use modified ctenes to chew or rasp flesh from the sea gooseberry. Over time, and repeated attacks, the sea gooseberry is damaged, diminished, and will eventually die.

Over a couple of weeks feasting on sea gooseberries the Beroe increase in size, and can reach a total length in excess of eight centimeters. The adult Beroe are able to ‘unzip’ their mouths, opening them wide enough to ingest Pleurobrachia whole, as seen in the photograph below:

Beroe itself is not without predators, however. In the photo below (same individual as above) you can see that the beroe is in turn being eaten by a ‘megalopa’ or juvenile crab.

I have often seen adult crabs eating jellyfish, and spider crabs will often climb kelp at the turn of the tide to catch moon jellies or lions manes that drift past, but this is certainly the most ambitious decapod I have ever seen! What goes around, comes around…

In the German Bight the appearance of Beroe results in a near total collapse of the Pleurobrachia plieus population in a matter of weeks(1). In the Wyre the population of Pleurobrachia falls significantly, but a continuous supply of larvae in the plankton ensures that the species is still present in our samples, and indeed it was Beroe that had disappeared from the sample on the 26th July 2022.

Reference

(1) Coastal Plankton 2nd Ed. by Otto Larink and Wilfried Westheide. Published 2011 Verlag Dr Friedrich Pfiel, Munchen (ISBN 978-3-89937-127-7). p74.

Barry Kaye, Lancashire MCS

From the start of 2022 Mark Woombs, Jean Wilson and myself have been sampling plankton every fortnight from the river Wyre estuary at Knott End. The intention of this study is to refresh our understanding of plankton diversity and dynamics in the Bay area, and contribute to studies on the health of the River Wyre. Phytoplankton – microscopic marine plants – are the base of the marine food web, and contribute approximately 50% of the oxygen we breathe, whilst quietly sequestering atmospheric carbon dioxide. Zooplankton are (generally microscopic) animals that convert phytoplankton biomass into food that is accessible to the rest of the animals in the world’s oceans.

In estuarine systems there is never really a shortage of plant neutrients. As a consequence there is the opportunity for phytoplankton to be present in high numbers from early spring, as light levels and surface water temperatures rise, through to late autumn, when grazing combined with lowered growth rates (due to reduced light and temperature) finally cut the poulations back.

This does not mean, however, that the same phytoplankton species dominate our samples throughout the year. In fact, our study to date has revealed a dynamic interplay between phytoplankton species, with different species commming to dominate the total population in succession. The most likely cause of the species population collapses is disease, rather than grazing, though we only have direct evidence for this in one of our phytoplankton families, the Coscinodiscus, where the appearance of the fungal disease Lagenisma coscinodisci in late May coincided with a decline in the numbers, particularly of C. wailesii, which had been the dominant member of the Coscinodiscus to that point.

Plankton species taken during the sampling program were used to illustrate our talk to the Royal Society of Biology on 21st May, but we will have a more complete picture of plankton activity in the Wyre at the end of the year, and hope to present this work in more detail then.

Barry Kaye, Lancashire MCS

Our annual AGM will be on Wednesday the 21st April 2021, at the start of our regular Zoom meeting entitled ‘There’s something swimming in my soup…’. The meeting will look at Zooplankton from around the West Coast of the UK. These tiny animals form a vital part of the marine ecosystem, eating the even tinier phytoplankton, and in turn being eaten by a whole range of larger marine predators.

A note for the AGM – we welcome input from everyone; but you must be a member of National MCS to vote on financial matters!

Zoom connection details have been sent out in this month’s newsletter, please contact me if you have not received your invitation, and would like to be included in our mailing list!

Our online ID course on Wednesday 20th January 2021 will look at some of the most common phytoplankton sampled from the Morecambe Bay area and the West Coast of Scotland. This is a basic introduction to sampling and identification.