Penny Johnes
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pennyjohnes.bsky.social
Penny Johnes
@pennyjohnes.bsky.social
870 followers 550 following 260 posts
Professor of Biogeochemistry, UBris. Researches freshwater nutrient pollution and biodiversity loss in lakes, rivers and wetlands, and mitigation strategies. Nitrogen, phosphorus, carbon, isotopes, dissolved organic matter.

ORCiD: 0000-0003-1605-6896
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pennyjohnes.bsky.social
And that's the final @erc.europa.eu @ercrefresh.bsky.social stream isotope experiment of our 2025 field season complete. With many thanks to @bristoluni.bsky.social PhD students Matt McCormack and Boyi Li for their help with eDNA sampling and completing site decommissioning before the rain arrived 🧪
James McDonald snd Matt McCormack extracting mesocosms from frames Native aquatic snails collected 4 days after introduction to jars with 15N13C labelled biofilms and bryophytes. Matt and Boyi transferring heated mesocosms to the bank for eDNA and eRNA extraction, led by Martin Genner Leave no trace! Site returned to its original state after decommissioning. With many thanks to Bannau Brycheiniog National Park Authority for permission to work on the land.
August 27, 2025 at 10:46 AM
pennyjohnes.bsky.social
All fieldwork is now complete on our ukri.org @quantumfreshwaters.bsky.social project including sampling in 60 UK livestock farming headwater streams. We now focus on sample and data analyses, while we build models to test the likely efficacy of mitigation efforts to reduce impacts on UK rivers 🧪
Ayrshire X cattle in Scotland with direct access to a headwater stream. Cattle having direct access to streams causes significant increase in water pollution risk. Dairy Holstein Friesian herd in Wales, outdoor grazed. Sheep typically have direct access to watercourses too. They too can markedly increase pollution in headwater streams.
August 23, 2025 at 12:15 PM
pennyjohnes.bsky.social
That's a wrap on our @erc.europa.eu @ukri.org @ercrefresh.bsky.social programme 2nd expt.. A very different environment than the chalk stream in our 1st expt. but nonetheless with wonderful biota: Beautiful Demoiselle damselflies fluttering around us, and freshwater limpets grazing our biofilms! 🧪
Male Beautiful Demoiselle damselfly, abundant at our clay stream site in SW England. Female Beautiful Demoiselle damselfly at our site. These damselflies frequently landed on us and our equipment as we worked. We found several of these small, native freshwater limpets on our biofilm slides when we extracted them. Ancylus fluvialitis.
August 6, 2025 at 8:38 AM
pennyjohnes.bsky.social
Our @ukri.org funded @erc.europa.eu REFRESH programme is going well! Chalk stream isotope dosing expt. complete, clay expt. nearly complete with help from our first PhD student, @durham-university.bsky.social graduate Matt McCormack. Peat expt. set-up now underway @bannaubrycheiniog.bsky.social 🧪🐟🌿🐌
Charlotte Briddon and Sydney Enns working on the ambient treatment mesocosms in our clay stream experiment. Sydney Enns wearing her chest waders. These neoprene waders are warm and keep us dry (mostly, as long as we avoid barbed wire punctures) but we do get buoyant feet when we sit down! Kind support from two volunteers: Nina Aspey, and Matt McCormack, Durham University Biological Sciences graduate who is joining us in the autumn as our first REFRESH PhD student. A successful day at our peat stream site today with James McDonald, setting up our biofilm cultivation slides so that they are ready for this final experiment in August. The sheep hurdles are to keep the sheep grazing this common out of the experiment!
July 31, 2025 at 6:51 PM
pennyjohnes.bsky.social
‪Great opportunity: full @ukri.org funded PhD Studentship with 4 years fees, stipend (£19237 pa) and full Research Training Support Grant, working with Prof Ian Bull, Director of the National Environmental Isotope Facility and my
@ercrefresh.bsky.social team! Starts 10/2025 shorturl.at/AJREj 🧪
An algal bloom on a nutrient enriched lake encroaches into the Nymphaea alba and Chara hispida beds, causing plant dieback. Your work will develop a novel, targeted analytical method to allow us to rapidly screen samples to determine the molecular composition of the dissolved organic nutrients in these and other waters. These provide a critically important but overlooked nutrient resource driving ecosystem damage and biodiversity decline in waterbodies. We currently lack a unified technique that can rapidly screen samples in a targeted manner. You'll likely be highly motivated, enjoy both field and laboratory work, and be a good analytical chemist with attention to detail who is keen to make your mark through novel method development. Give Ian a ring or send him an e.mail (ian.d.bull@bristol.ac.uk), or contact me here or via my e.mail penny.johnes@bristol.ac.uk. We have a large team on the ERC REFRESH programme that you will be joining, along with two other PhD students due to start at the same time. Great team and learning opportunities.
July 11, 2025 at 2:38 PM
pennyjohnes.bsky.social
We've now completed our QUANTUM sampling at 33/60 sites, in SW of England, W England and Wales. Next stop N England and Scotland! By focusing on streams draining sheep, beef and dairy farmland, we are building a national picture of their impacts on UK river water quality to better inform policy.🧪
Lowland sheep impacts on streams sampled in SW England in our @ukri.org QUANTUM programme, with help from @a.castrocastellon.bsky.social Beef cattle typically (like sheep) have direct access to watercourses where there is defecation in the channel and poaching of stream bank sediments, contributing to a high risk of contaminant transfer to streams. We are testing samples to determine their ecotoxin, pathogen, nutrient and organic matter composition. In around 50% of dairy farmed catchments, outdoor-grazed livestock are able to directly access streams. This leads to the same impacts as in beef cattle systems. In the other 50%, where animals are housed, water is abstracted to provide the cows with the capacity to produce milk. The average production rate is 22 litres per cow per day, with some high yielding cows producting much more. If a farmer has a herd of 500 cows, this can amount to over 11000 litres of water per farm, exported from the catchment every day in the form of milk or milk products. As a result where there are large commercial herds kept indoors streams often run bone dry or at very low flows in the summer months, reducing their dilution capacity for contaminants, increasing environmental exposure rates for stream biota, and making the stream ecosystem much more susceptible to climate warming effects.
July 2, 2025 at 2:29 PM
pennyjohnes.bsky.social
When livestock have direct access to watercourses, the risk of ecotoxin, pathogen, organic matter and nutrient pollution increases to 100%. Our
@ukri.org QUANTUM programme sampling found some culprits today..... @acastrocastellon.bsky.social @victoriahussey.bsky.social 🧪🐄🐂
An idyllic scene, but hidden within is ecosystem damage as cattle urine and dung are directly voided into the stream or onto the stream margins. Some of the culprits Who did that? A contaminated site. Water flows from her to the river and out to coastal bathing waters. Contaminants include ecotoxins, pathogens, organic matter and nutrients.
June 25, 2025 at 12:10 AM
pennyjohnes.bsky.social
Our @ukri.org QUANTUM national sampling programme is now well underway. Thanks to @acastrocastellon.bsky.social for help with the SW England sites, Sydney Enns and @victoriahussey.bsky.social for prepping the kit, and my husband who helped with the Welsh sites - great cow poo sampling skills! 🧪🐄🐑🐂
Beef cattle, and a very aggressive bull guarding his herd. Dairy cattle in the Cleddau catchment Start of Day 3, in the headquarters of the Tywi catchment before heading over to the Usk. Days 1 and 2 sampled the Cleddau (W and E), Nyfer, Taf, Teifi and Aeron catchments! A sprightly cow during our sampling trip to the W Cleddau. Shout out to the West Wales Nutrient Management Partnership who put us in touch with the farmers, and the farmer who gave us permission to visit their farms.
June 23, 2025 at 9:56 PM
pennyjohnes.bsky.social
As we finish our NERC QUANTUM field experiments and move on to upscaling and modelling work at national scale, we'd like to thank the residents of Rickford and our hugely helpful farmers, Paul and Roger Keel for their support. We'll return in the autumn to tell you what we've found!
Roger Keel, ready to repair the fencing in our enclosure prior to letting the extensive beef cattle back in to graze off the lush grass on our slurry amended plots. @acastrocastellon.bsky.social, @jameslmcdonald.bsky.social, @bristoluni.bsky.social Paul and Roger Keel in conversation with Catchment Sensitive Farming officers at our autumn stakeholder event. Paul in conversation with Ed Fredenham of Bristol Water, during our autumn stakeholder event.
May 29, 2025 at 5:12 PM
pennyjohnes.bsky.social
Last day in the field, returning our NERC QUANTUM field kit to the @bristoluni.bsky.social Fenswood field store where we bumped into our Aviation Engineering colleagues flying drones. They kindly agreed to fly over our field site producing aerial images for our future presentations. Great teamwork!🧪
Aviation Engineering PhD students from University of Bristol, flying a drone over our field site to capture aerial images of the impacts of slurry amendments on vegetation growth. Very grateful to them, as we interrupted them at their summer BBQ and drone festival. Good spot by our new research team member, @jameslmcdonald.bsky.social‬ Drone at the field site, set up to capture aerial and multi-spectral data. Drone flying over our field site at Rickford, N Somerset. @acastrocastellon.bsky.social, @jameslmcdonald.bsky.social‬ Kilian Meier, 2nd year PhD student in the @bristoluni.sky.social Aviation Engineering group, flying a drone over our field site at Rickford, N Somerset.
May 29, 2025 at 4:58 PM
pennyjohnes.bsky.social
Final day of sampling today for the @bristoluni.bsky.social
team at our NERC QUANTUM field site, and the
@exeter.ac.uk QUANTUM team completing their field ecotoxin exposure experiments. This was a fantastic field site for the project. Many thanks to the farmers and villagers for their support.
Professor Charles Tyler, University of Exeter, who leads the QUANTUM programme ecotoxicology work, holding a sample of three-spined stickleback following our field ecotoxin exposure experiments. The University of Exeter Biosciences field team, led by Dr Anke Lange, processing samples from the QUANTUM field ecotoxicology experiment Dr Simona Frustaci, another of our QUANTUM programme PDRAs, with a sample of freshwater shrimp, Gammarus pulex, following the QUANTUM field ecotoxin exposure experiments. Sydney Enns, who with @jameslmcdonald.bsky.social‬, @acastrocastellon.bsky.social‬ and @pennyjohnes@bsky.social, spent the day decommissioning the site, recovering our key for cleaning and prep for other projects, and tidying up the site ready for the cattle to return to the site next week. We also spent the afternoon collecting a final set of soil samples from our control, 40m and 10m slurry amendment plots, to explore downslope nutrient trends (from hillslope to stream) following a year of slurry amendments.
May 28, 2025 at 6:19 PM
pennyjohnes.bsky.social
We had warm sunny weather when we wanted rain for our experiments and now, when we want dry weather to for soil coring and site decommissioning, we had very heavy rain all day. Even so, 62 coring sites surveyed in and cored for our NERC QUANTUM ecotoxin, pathogen, organic and nutrient analyses! 🧪
Prof Andy Binley, Lancaster University with Tony Healey, technical manager at the University of Bristol, surveying in the soil coring sites with the help of Prof Penny Johnes So course extracted ready for ecotoxin pathogen organic geochemistry and nutrient analysis at the universities of Bath, Bangor and Bristol respectively. 62 corling sites across our control strips and our two slurry amended treatment strips. Dr Ana Castro-Castellon with Prof Penny Johnes, midway through coring and both of us thoroughly soaking wet but still cheerful! Dr. Victoria Hussey, Sydney Enns and Dr James McDonald at the start of coring. Six sites into the 62 at 10 am and everyone was already soaked.
May 27, 2025 at 5:36 PM
pennyjohnes.bsky.social
More fieldwork fun for QUANTUM and REFRESH teams today. A visit from Welsh Rivers Union, then started site decommissioning following completion of our experiments, and marked up a sample grid for soil coring on our slurry amendment plots next week. Curious cattle made leaving the site tricky! 🧪🐄🐮
Cattle rushing to the fence to find out what we were doing as we marked up the soil coring locations for next week Cattle peering into our field vehicle to check out our supplies and tool kits. Ana trying to chase the cattle away from the gate so we could leave the field experimental area without letting them in to feast on the rich grass on the slurry amended plots
May 23, 2025 at 3:43 PM
pennyjohnes.bsky.social
More knowledge exchange and training on the NERC QUANTUM isotope dosing platform, with researchers working with us from the ERC REFRESH and NERC MICRO-CYCLE teams as we collect our 96 hr gas, biofilm and moss samples, and add snails for the final 96 hr period. Final 192 hr samples next week! 🧪
Nellie Farhoudi, specialist research technician on the NERC MICRO-CYCLE programme. Drs Michaela Reay (NERC MICRO-CYCLE) and Ana Castro-Castellon (NERC QUANTUM) PDRAs, downloading our temperature and light sensor data. Pond snails, Lymnaea stagnalis, ready to add to our mesocosms. Today's team: DrJames McDonald (ERC REFRESH), Dr Michaela Reay and Nellie Farhoudi (NERC MICRO-CYCLE) and Dr Ana Castro-Castellon (NERC QUANTUM) after finishing sampling.
May 16, 2025 at 5:17 PM
pennyjohnes.bsky.social
Meet Dr Tolulope Lawrence, one of four PDRAs on our NERC QUANTUM project, who has been presenting at SETAC on her work with Prof Barbara Kasprzyk Hordern, University of Bath, on the analysis of our livestock excreta and freshwater samples for 200 ecotoxin compounds. Great work Tolu! 🧪
SETAC meeting Vienna 2025 Dr Tolulope Lawrence with her SETAC poster Arriving at SETAC
May 15, 2025 at 7:06 AM
pennyjohnes.bsky.social
Doing great science requires a great team. Introducing Dr Ana Castro-Castellon, PDRA on the NERC QUANTUM project, freshwater ecology and chemistry specialist with field electronics skills. Pictured after getting all 45 motors working on our stream isotope experiment. Great to work with you, Ana! 🧪🪛🛠️
Prof Penny Johnes and Dr Ana Castro-Castellon of the NEEC QUANTUM project. Great to have these skills in the team Ana!
May 14, 2025 at 4:45 PM
pennyjohnes.bsky.social
Our final NERC QUANTUM isotope dosing experiment is now underway! Exciting science. Looking forward to comparing May results with Nov expt outcomes, and discovering the impacts of warming effects to RCP 6.0 on stream processing and biotic uptake of livestock-derived DOM as a nutrient resource.🧪🌿🐌💧
Bryophytes and biofilm slides ready for the experiment, and for sampling at 6 x time points over 8 days Adding 13C15N labelled isotopes to our mesocosms Sampling gaseous phase emissions from the mesocosms at 6 hr time point. We did try to avoid sampling at night, but setting up and checking motors/paddles etc always takes longer than you hope. Bryophute sample 6 hr after dosing with 13C15N labelled glucosamine.
May 13, 2025 at 1:57 PM
pennyjohnes.bsky.social
Nearly all our NERC QUANTUM postdocs and techs on site today to finalise our warming experiment design, and set up Chemcatchers and maintain fish and invert populations in our field ecotox exposure experiments. Universities of Bristol, Exeter and Bath #multidisciplinary #collaboration #fun-science
Penny Johnes (PI, NERC QUANTUM and ERC REFRESH via UKRI) with Ana Castro-Castellon and Sydney Enns (University of Bristol, QUANTUM), James McDonald (University of Bristol, ERC REFRESH), Tolulope Lawrence (University of Bath, QUANTUM), and Anke Lange and Simona Frustaci (University of Exeter, QUANTUM). Setting up the Chemcatchers under expert guidance from Tolu. Simona and Tolu with Chemcatchers deployed Chemcatcher, showing internal SPE membranes.
May 8, 2025 at 1:28 PM
pennyjohnes.bsky.social
Great to have Hannah Champion of JBA Consulting in the field with us today as we fine-tune our warming approach for our final forthcoming @nerc.bsky.social QUANTUM isotope dosing experiments next week. Informing our collaborative modelling with field experience!🧪
Hannah Champion with Ana Castro-Castellon, PDRA on our NERC QUANTUM programme. Penny Johnes setting up pilot warming treatments to inform our final QUANTUM stream isotope dosing experiments. We aim to generate a 2.3 degree C warming and compare uptake and metabolic rates with those same treatments at ambient stream temperatures. Initial warming treatments in situ. Generated 1-2 degrees C daytime warming, but night-time cooling. We are now experimenting with black neoprene mats and bubble wrap jackets, to achieve the desired warming effect.
May 7, 2025 at 1:44 PM
pennyjohnes.bsky.social
Great day setting up a pilot stream warming experiment for our upcoming NERC QUANTUM isotope experiment with our newest recruit, Dr James McDonald who has just joined our NERC funded ERC Advanced Grant REFRESH team. Knowledge transfer at its best!🧪
Professor Penny Johnes in the experimental stream site for the QUANTUM programme. Dr Ana Castro-Castellon, QUANTUM PDRA with Dr James McDonald, REFRESH Specialist Research Technician, installing mesocosms in our freshly cleaned frames in the stream. The final pilot study. With jars raised out of the stream at various Heights to test the appropriate stream depth at which we can achieve a 2.3 degree C warming effect in the mesocosms. Results will inform our final installation for our second and final isotope dosing experiment at the site. Results from the November experiment have been very promising and we look forward to comparing them with the May experiment, and comparing the ambient mesocosm results with those from the warmed jars. Installing the temperature and light sensors, together with the paddle to stir the jars to ambient stream flow velocities
May 2, 2025 at 5:03 PM
pennyjohnes.bsky.social
Lovely day in the field, setting up our final
field experiments exploring stream ecotoxin exposure for fish and invertebrates, slurry contaminant transfers from land to stream, and livestock excreta as an organic nutrient source for biofilms, mosses and snails.🧪
A lowland eutrophicated lake Ewe with lambs
April 30, 2025 at 8:34 PM
pennyjohnes.bsky.social
Our final www.quantumfreshwaters.org slurry amendment experiment has now started, and we're hoping the promised rain arrives to flush the plots to the stream this time! In parallel our @uoebiosciences.bsky.social team are gearing up for our field ecotoxin exposure experiments! 🧪
Cattle slurry being applied to land 10m from the stream at our experimental stream site, in accordance with current Government guidelines for Good Agricultural Practice and Farming Rules for Water. It won't take much rain to flush this straight to the stream. Fish cages now installed at our monitoring stations upstream and downstream from our slurry amendment plots. Just waiting for some rain, then we'll add the fish and invertebrates to track ecotoxin exposure responses. The University of Exeter Biosciences field team in action, led by Professor Charles Tyler
April 15, 2025 at 3:52 PM
pennyjohnes.bsky.social
Lovely day for our NERC QUANTUM project, with thanks to Nellie Farhoudi from our NERC MICRO-CYCLE team for her help: sampling, calibrating sondes and setting-up for our final experiments determining livestock impacts on freshwaters - 1) slurry amendments, 2) ecotoxin exposure, 3) isotope dosing 🧪🐟🌿🐌
Sydney Enns with a water sample (collected in glass to avoid plastic contamination) for our molecular scale dissolved organic matter analyses, and Nellie Farhoudi with a water sample for our colleagues at University of Bath who are analysing for ecotoxins derived from livestock excreta. Nellie and Sydney, after we had cleared gravel build up around the stilling well for our Hobo water level recorded, and set it vertically, ready for our final period of observations. The stream has a dynamic morphology, and we need to carefully check and reposition equipment, clearing gravel and plant debris each week, to ensure the quality of our sensing data streams.
April 1, 2025 at 11:54 AM
pennyjohnes.bsky.social
The #NERC QUANTUM freshwaters team in the field today, with the second of 3 slurry amendments to land 40m and 10m from the stream, ready for our April field experiment. Precision spreading following official Government guidance gov.uk/guidance/sto.... Will increase to 40m help reduce risks? 🧪
A tractor spreading slurry within 10 m of a watercourse, using a precision application approach Land 10 m from a watercourse, after a precision application of slurry What 10 m from the stream looks like, on the ground, with surface ponding of slurry immediately upslope from a watercourse. A 'buffer zone' of 10 m is current Government guidance for protection of watercourses in the UK.
March 17, 2025 at 12:13 PM
pennyjohnes.bsky.social
Do come along to our webinar tomorrow, and find out how we're getting on with our work to characterise the risks to freshwaters from livestock farming. Follow the link below to register: water.leeds.ac.uk/events/uk-fr... 🧪🐄🐂🐏
Watering of cattle in streams provide a direct route for contaminants in livestock excreta to reach watercourses. Photo of a cow in a stream. Livestock excreta include farmyard manure spread to lack via muckspreading, slurry, spread as a liquid onto crops and grass and often attracting seagulls as shown in this photo, and directly voided dung and urine. Photo shows the range of organic excreta commonly produced in livestock farming. Photo March 2025.
March 11, 2025 at 5:08 PM