Are there any advantages to lake eutrophication? – A carbon sink perspective.

The eutrophication (or excessive enrichment by nutrients as a result of human activities) of lowland lakes is a widespread problem globally but is particularly serious in densely populated areas of Europe and North America.

While the negative effects of nutrient enrichment are considerable in term of biodiversity loss and alterations in ecosystem functioning, one possible positive aspect is the increased rate of organic carbon burial. This means that regional carbon budgets may benefit from eutrophication, leading to a positive effect on climate regulation.

The possible climate regulating role of lakes as carbon sinks is only now being evaluated but to date there has been limited consideration of change in organic carbon burial rates in response to eutrophication.

A recently published study by Helen Bennion, one of the Lake BESS team, with John Anderson (Loughborough University) and Andy Lotter (Utrecht University) has revealed that the accumulation rates of organic carbon in many European lakes have increased by at least four to five fold over the last 100-150 years (Anderson et al., 2014).

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Pollution with an excess of nutrients coming from human activities led to increased carbon sequestration rates in European lakes during the 20th century. Photo by Ben Goldsmith.

This piece of research compiled data from about 90 European lakes and found background estimates of carbon burial ~ 5–10 g C m-2 yr–1 compared with an average rate of around 60 g C m-2 yr–1 for lakes subject to eutrophication in recent decades.

They show that the organic carbon burial rates for European eutrophic lakes reflect phosphorus availability – a pollutant coming for example from domestic waste waters and farming – and are considerably higher than previously thought. This has clear implications for our current estimates of regional carbon budgets and for the role lakes may play.

The authors suggest that enhanced organic carbon burial by lakes is one positive side-effect of the otherwise negative impact of the anthropogenic disruption of nutrient cycles: eutrophic lakes are sequestering more organic carbon than at any other time in their history.

Within the Lake BESS project, changes in organic carbon burial rates will be calculated for the study sites in the two lake regions to determine the role of these lakes as carbon sinks and hence in providing the important ecosystem service of climate regulation.

Reference: [include link]

Anderson N.J., Bennion H. & Lotter A.F. (2014) Lake eutrophication and its implications for organic carbon sequestration in Europe. Global Change Biology 20, 2741–2751. doi: 10.1111/gcb.12584

Lake BESS meeting

It has been a very busy summer and autumn for Lake BESS hence a reduction in post on this website. Lake BESS 2014 activities culminated in a meeting in UCL attended by most of us. We had a special guest, Geoff Philips, now honorary fellow at Stirling University, who is bringing exceptional expertise in water chemistry and in the functioning of the Broads system. He was also the only one of us remembering to take a picture! – thank you Geoff for coming and for sharing this picture:

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Back from the field!

We’re just back from our very successful field work around the Upper Lough Erne, Co. Fermanagh, Northern Ireland. We managed to survey nearly 20 satellite loughs for aquatic plants, water chemistry and bryozoans (see this previous post).

Corracoach Lough

Access to some of the lough was sometimes tough but always rewarding. Photography by Helen Bennion.

The help we received from volunteers and project partners was absolutely tremendous! Over the two week we have been a dozen of us actively involved in this research campaign. We’d particularly like to thank Hannah, Robert, Tim and Stephen for joining our team at this occasion and also all the land owners who were kind enough to grant us access to the lakes we had targeted.

Battling through reed beds to get onto some of the lough with our boats was one of the striking aspects of this field work! But it was worth the effort and the diversity of aquatic plant observed over the two week is very impressive. For instance we have sightings for at least ten different Potamogeton species (see this previous post), an extremely good score!

We’ll post more picture and reports from this field work in the coming weeks.

P. perfoliatus

Potamogeton perfoliatus (Photograph by Ben Goldsmith)

How do bryozoans travel?

‘How do bryozoans travel?’ is one of the questions we are going to address within our project. Beth Okamura is telling more about this aspect of our work:

“This summer we are planning to collect dormant propagules called statoblasts that are produced by freshwater bryozoans (see what bryozoans are on wikipedia). We will focus on the spined statoblasts produced by the lovely Cristatella mucedo.

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According to the Victorian naturalist George Allman , whose classic figure of Cristatella appears above, “a more interesting and beautiful animal than […] Cristatella mucedo can scarcely be imagined” (Allman 1856), an opinion that at least one of us adheres to – guess who! (ed. note: Beth is world-leading expert on Bryozoan, see her profile at the Natural History Museum).

Allman’s figure depicts a colony of Cristatella with various tentacular crowns (each about 1 mm) raised in filter feeding, the entire colony being drooped over and encircling aquatic vegetation. The figure also shows the spined statoblasts (also about 1 mm) in various developmental stages.

Statoblasts of Cristatella become attached to waterfowl (facilitated by their spines) and also, being buoyant, they initially float.

We aim to bolster our BESS project by examining relative levels of gene flow between Cristatella populations in sites associated with the Lough Erne and the Norfolk Broads systems, hypothesising that gene flow will be greater amongst sites in the more highly connected Lough Erne system.

The work is in collaboration with Hanna Hartikainen at ETH, Zurich.”

 

Pondweeds

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Pondweeds

The islands of Britain and Ireland have over 40 species or hybrids of pondweeds (genus Potamogeton). This diversity in pondweed is one of the highest in Europe with most European species being represented. Unfortunately local diversity and abundance of pondweeds have declined over the 20th Century, as a result of habitat destruction and pollution. The Upper Lough Erne region and The Broads are two areas of importance for the conservation of pondweed – but “what can we learn from these strongholds?” and “what measure could enhance their recovery nationally?” are questions we are trying to address part of the Lake BESS project. (Photo by Ambroise Baker: P. polygonifolius in full bloom).

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8th Shallow Lakes Conference

This conference will take place October 12 – 17, 2014 in Antalya, Turkey and anyone with an interest in shallow lake ecosystems is invited to take part. There will be several famous researchers presenting their work, such as John Smol from Queen’s Univerity (Canada) and Luc De Meester from the Univerity of Leuven (Belgium), poster sessions and field excursions.

A short film about the management of biodiversity and water in the Broads.

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“In this short film I asked some of the people I work with about the management of biodiversity and water in Broadland. Their thoughts are set alongside some of the most beautiful photos of wildlife and wetland landscapes. We hope you enjoy it” Andrea Kelly Senior Ecologist at the Broads Authority

BESS Science meeting

Lake BESS scientists Nigel Willby and Ambroise Baker attended the BESS Science meeting on April 1st and 2nd in York. It was extremely interesting to hear about the progress of other projects part of the same research programme about Biodiversity, Ecosystem Services and Sustainablility.

We presented our research plans and highlighted the complex relationship between drivers of change and ecosystem services with this slide:

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The BESS programme addresses a broad range of services but we were impressed by the prominent role of cultural ecosystem services across projects, research areas and ecosystem types. Their quantification and mapping remains an arduous task and much work is on the way.

We also heard sobering thoughts about alternative regimes and tipping points in ecosystems by Adrian Newton from the University of Bournemouth. It will be important to better understand how such rapid and unpredictable changes in ecosystems can have an impact on service delivery over time.

Zebra mussel from Kilturk Lough

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Zebra mussel from Kilturk Lough

But is it a zebra or is it a butterfly? Project partner Jorge Salgado suggests: “It’s a unique butterfly species with mussel wings that only inhabits the the Upper Lough Erne.”

Zebra mussel is an invasive mussel that was first observed in Ireland in 1997 but is now becoming widespread. It can use native mussel shells as substrate, as shown on this photograph taken by Jorge Salgado.

You can read about Zebra mussel in Northern Ireland in a this Zebra Mussel Management Strategy report.