̽��ֱ�� of Cambridge - freshwater

New approach to monitoring freshwater quality can identify sources of pollution, and predict their effects

jg533 — Thu, 28 Mar 2024 18:00:43 +0000

̽��ֱ��source of pollutants in rivers and freshwater lakes can now be identified using a comprehensive new water quality analysis, according to scientists at the ̽��ֱ�� of Cambridge and Trent ̽��ֱ��, Canada.

Microparticles from car tyres, pesticides from farmers’ fields, and toxins from harmful algal blooms are just some of the organic chemicals that can be detected using the new approach, which also indicates the impact these chemicals are likely to have in a particular river or lake.

Importantly, the approach can also point to the origin of specific organic matter dissolved in the water, because it has a distinct composition depending on its source.

̽��ֱ��approach uses a technique called high-resolution mass spectrometry to analyse water samples: within an hour this provides a comprehensive overview of all the organic molecules present.

Water quality is strongly determined by the diversity of organic matter dissolved in it – termed ‘chemodiversity.’ ̽��ֱ��scientists say that the thousands of different dissolved organic compounds can keep freshwater ecosystems healthy, or contribute to their decline, depending on the mixture present.

̽��ֱ��paper is published today in the journal Science.

“Traditional approaches to monitoring water quality involve taking lots of different measurements with many devices, which takes a lot of time. Our technique is a very simple way to get a comprehensive overview of what’s going on in a particular river or lake,” said Jérémy Fonvielle, a researcher in the ̽��ֱ�� of Cambridge’s Departments of Plant Sciences and Biochemistry, and co-author of the paper.

To understand what drives this chemodiversity, the team reviewed studies of dissolved organic matter in freshwater samples from rivers and lakes across Europe and northern Canada.

For example, water analysis of Lake Erie in Canada revealed high levels of phosphorus pollution. By looking at the composition of individual molecules in the water sample, researchers identified agricultural activities as the source of this pollution, rather than wastewater effluent.

“Whereas before, we could measure the amount of organic nitrogen or phosphorus pollution in a river, we couldn't really identify where pollution was coming from. With our new approach we can use the unique molecular fingerprint of different sources of pollution in freshwater to identify their source,” said Dr Andrew Tanentzap at Trent ̽��ֱ�� School of the Environment, co-author of the report.

Traditional approaches involve separately measuring many indicators of ecosystem health, such as the level of organic nutrients or particular pollutants like nitrogen. These can indicate the condition of the water, but not why this state has arisen.

Dissolved organic matter is one of the most complex mixtures on Earth. It consists of thousands of individual molecules, each with their own unique properties. This matter influences many processes in rivers and lakes, including nutrient cycling, carbon storage, light absorption, and food web interactions - which together determine ecosystem function.

Sources of dissolved organic matter in freshwater include urban runoff, agricultural runoff, aerosols and wildfires.

“It's possible to monitor the health of freshwater through the diversity of compounds that are present. Our approach can, and is, being rolled out across the UK,” said Tanentzap.

Fonvielle will now apply this technique to analysing water samples from farmland drainage ditches in the Fens, as part of a project run by the ̽��ֱ�� of Cambridge’s Centre for Landscape Regeneration to understand freshwater health in this agricultural landscape.

̽��ֱ��research was funded primarily by the Natural Sciences and Engineering Research Council and the European Research Council.

Reference: Tanentzap, A.J. and Fonvielle, J.A: ‘Chemodiversity in freshwater health.’ Science, March 2024. DOI: 10.1126/science.adg8658

Analysing the diversity of organic compounds dissolved in freshwater provides a reliable measure of ecosystem health, say scientists.

Our technique is a very simple way to get a comprehensive overview of what’s going on in a particular river or lake.

Jérémy Fonvielle

Sam Woodman

Study lake in Norway

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Britain on brink of freshwater species ‘invasion’ from south east Europe

fpjl2 — Mon, 13 Oct 2014 09:42:10 +0000

Five of the most high-risk freshwater invaders from the Ponto-Caspian region around Turkey and Ukraine are now in Britain - including the quagga mussel, confirmed just two weeks ago on 1 October in the Wraysbury River near Heathrow airport.

Researchers say that, with at least ten more of these high-risk species established just across the channel in Dutch ports, Britain could be on the brink of what they describe as an ‘invasional meltdown’: as positive interactions between invading species cause booming populations that colonise ecosystems - with devastating consequences for native species.

̽��ֱ��authors of a study on 23 high-risk invasive species, published in the Journal of Applied Ecology, describe Britain’s need to confront the Ponto-Caspian problem - named for the invaders’ homelands of the Black, Azov and Caspian seas - as a 'vital element for national biosecurity'.

They say monitoring efforts should be focused on areas at most risk of multiple invasions: the lower reaches of the Rivers Great Ouse, Thames and Severn and the Broadlands, where shipping ballast water and ornamental plant trading is most likely to inadvertently deposit the cross-channel invaders.

All of these areas are projected to see an influx of up to twenty Ponto-Caspian invading species in the near future.

“Pretty much everything in our rivers and lakes is directly or indirectly vulnerable,” said Dr David Aldridge, co-author from the ̽��ֱ�� of Cambridge’s Department of Zoology, who confirmed the quagga find.

“ ̽��ֱ��invader we are most concerned about is the quagga mussel, which alarmingly was first discovered in the UK just two weeks ago. This pest will smother and kill our native mussels, block water pipes and foul boat hulls. We are also really worried about Ponto-Caspian shrimps, which will eat our native shrimps.”

̽��ֱ��most aggressive invasive shrimp have ominous monikers: the demon shrimp, bloody red shrimp and the notorious killer shrimp - dubbed the ‘pink peril’.

These organisms have already been recorded in Britain, and experts warn they will act as a gateway for further species due to favourable inter-species interactions that facilitate invasion, such as food provision and ‘commensalism’ - in which one species obtains benefits from another’s place in an ecosystem.

̽��ֱ��researchers point to the example of the zebra mussel, a Ponto-Caspian outrider and relation of the quagga first seen in the UK in 1824 and now widespread. Zebra and quagga mussels smother Britain’s native mussels, preventing them from feeding and moving. ̽��ֱ��invading mussels also provide an ideal home for Ponto-Caspian amphipods such as killer and demon shrimps, which have striped patterns to blend in with the mussels’ shells.

These amphipods, in turn, provide food for larger invaders such as goby fish. Ponto-Caspian gobies have now made their way down the Rhine, one of the main “corridors” to Britain, with populations exploding in the waterways of western France over the last few years. ̽��ֱ��invading gobies eat native invertebrate and displace native fish such as the already threatened Bullhead.

Once the Ponto-Caspian species reach coastal areas of ̽��ֱ��Netherlands, they are transported across the channel in ballast water taken on by cargo ships, or hidden in exported ornamental plants and aquatic equipment such as fishing gear.

“If we look at ̽��ֱ��Netherlands nowadays it is sometimes hard to find a non-Ponto-Caspian species in their waterways,” said Aldridge.

“In some parts of Britain the freshwater community already looks more like the Caspian Sea. ̽��ֱ��Norfolk Broads, for example, typically viewed as a wildlife haven, is actually dominated by Ponto-Caspian zebra mussels and killer shrimps in many places.”

“Invasive species – such as the quagga mussel – cost the UK economy in excess of £1.8 billion every year,” said Sarah Chare, deputy director of fisheries and biodiversity at the UK Environment Agency.

“ ̽��ֱ��quagga mussel is a highly invasive non-native species, affecting water quality and clogging up pipes. If you spot one then please report it to us through the online recording form.”

Through an in-depth analysis of all reported field and experimental interactions between the 23 most high-risk invasive Ponto-Caspian species, the researchers were able to identify 157 different effects - the majority of which enabled positive reinforcement between species (71) or made no difference (64).

Dates and locations of the first British reports of 48 other freshwater invaders from around the world show that 33% emerged in the Thames river basin, making it the UK hot spot for invaders, followed by Anglian water networks (19%) and the Humber (15%).

̽��ֱ��time between a Ponto-Caspian species being reported in ̽��ֱ��Netherlands and Britain has shrunk considerably - from an average of 30 years at the beginning of the 20th century to just 5 in the last decade.

“Due to globalisation and increased travel and freight transport, the rate of colonisation of invasive species into Britain from ̽��ֱ��Netherlands keeps accelerating - posing a serious threat to the conservation of British aquatic ecosystems,” said co-author Dr Belinda Gallardo, now based at the Doñana Biological Station in Spain.

“Cross-country sharing of information on the status and impacts of invasive species is fundamental to early detection, so that risks can be rapidly assessed. A continuing process for evaluating invasive species and detecting new introductions needs to be established, as this problem is increasing dramatically.”

Inset image: 'Killer' shrimp by Thomas Smith/Environment Agency

New research shows multiple invasive species with the same origin facilitate each other’s ability to colonise ecosystems. By studying how these species interact as well as current population locations, researchers believe that Britain is heading for an ‘invasion meltdown’ of freshwater species from south east Europe.

Pretty much everything in our rivers and lakes is directly or indirectly vulnerable

David Aldridge

David Aldridge/Thomas Smith via Environment Agency

Top: quagga mussel hitching a ride on a zebra mussel. Bottom: killer shrimp

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