Manipulating the chemosynthetic and photosynthetic support of river food webs
Lead Research Organisation:
Queen Mary University of London
Department Name: Sch of Biological and Chemical Sciences
Abstract
We are probably all familiar with the basic principle that life on earth is reliant on primary production i.e. photosynthetic plants driven by energy from the sun. There was a great deal of interest in 1977 when images of bizarre 6ft tubeworms and giant clams came up from the depths of the Pacific to reveal significant production, indeed whole communities reliant upon chemical energy (chemosynthesis). Few, if any, would suspect that such chemosynthetic life may be significant in the classic chalk rivers of southern England. However, a fortuitous finding, as part of a wider NERC LOCAR project into the ecological significance of river water and groundwater exchange, suggests that this is the case. We measured the stable carbon isotope values of common aquatic invertebrates (small crustacea and insects) and their putative food sources in one of our focal model systems (the River Lambourn) because we can use stable isotopes to trace energy sources and fluxes through food webs. Whereas the values for small shrimps and blackfly larvae reflected that of the dominant photosynthetic production, the cased larvae of the common caddisflies were distinctly different. Remarkably, such isotope values characterise an input of methane-derived carbon and our calculations suggest that the caddisflies were receiving a 20-25 % chemosynthetic carbon 'subsidy'. Freshwater may comprise only 3% of the Earth's total water, and rivers a vanishingly small percentage of that, yet it is this tiny percentage with which we think we are most familiar, and upon which we rely in our everyday lives. Our earlier research suggests we do not know as much about the processes in rivers as we first thought; a completely novel source of carbon, in effect, fuelling life in the river. Of course, methane is a powerful greenhouse gas and the more we know about how it is produced and cycled in the environment, the better. These first findings prompted us to examine the relative proportion of chemosynthetic to photosynthetic production under simple conditions in the laboratory and we showed that chemosynthesis was indeed a significant source of energy; around 6% but with the potential to be higher under natural conditions. What we need to do now is to scale up these simple measurements in the laboratory to realistic field-trials in which we can manipulate both the amount of methane and sunlight. Then we can map the stable isotope 'patterns' we see in the insects directly onto the processes which we hypothesised were the drivers of that pattern and close this knowledge gap. At the River Laboratory of the Freshwater Biological Association, there are a number of stream channels which we can use as the basis for our experimentation, although we will need to modify those to our specific requirements. The channels are fed with water from the R Frome which we have previously found to have the highest summer concentration of methane, ideal for our experiments. In a series of experiments, we will manipulate methane concentration, sunlight and animal numbers, while measuring concurrent photosynthetic and chemosynthetic production. If we can demonstrate that the whole food web, including the plants, are ultimately affected by methane cycling, then our first calculations of the importance of methane subsidy (20-25%) are underestimates, and chemosynthetic production is even more important to the life in these rivers. In summary, we will combine the traditional river ecology expertise of Hildrew and Woodward, with the stable isotope expertise of Grey, and gas and nutrient cycling expertise of Trimmer in a new collaboration to re-appraise how productivity in our rivers is governed.
Organisations
- Queen Mary University of London (Lead Research Organisation)
- QUEEN MARY UNIVERSITY OF LONDON (Collaboration)
- UK CENTRE FOR ECOLOGY & HYDROLOGY (Collaboration)
- WasserCluster Lunz Biological Station GmbH (Collaboration)
- Freshwater Biological Association (Collaboration)
- University of Jyväskylä (Collaboration)
Publications
Shelley F
(2014)
Widespread methanotrophic primary production in lowland chalk rivers.
in Proceedings. Biological sciences
Shelley F
(2014)
Microbial methane cycling in the bed of a chalk river: oxidation has the potential to match methanogenesis enhanced by warming
in Freshwater Biology
Trimmer M
(2015)
Riverbed methanotrophy sustained by high carbon conversion efficiency.
in The ISME journal
Grey J
(2016)
The Incredible Lightness of Being Methane-Fuelled: Stable Isotopes Reveal Alternative Energy Pathways in Aquatic Ecosystems and Beyond
in Frontiers in Ecology and Evolution
Shelley F
(2017)
Bringing methanotrophy in rivers out of the shadows
in Limnology and Oceanography
Sampson A
(2019)
Geographically widespread 13 C-depletion of grazing caddis larvae: A third way of fuelling stream food webs?
in Freshwater Biology
Description | Typical rates of methane generation and oxidation by microbes in natural rivers (chalkstreams), and how that alters over seasons. The efficiency with which methane is converted into biomass, compared to carbon fixed via photosynthesis The relative contribution of methane-derived carbon and photosynthetically fixed carbon to river primary production under varying conditions of light / shade, and hence how important is each pathway to the higher food web. How those microbes that use methane may respond to aspects of climate change |
Exploitation Route | Better understanding of the microbial conversion of methane into biomass and how widespread a phenomenon it is, has implications for higher food web eg species of conservation concern such as salmonids. With reference to this research, it has since been found that a significant proportion of commercially important lobster fisheries comprises chemosynthetic production Better understanding of the conversion of organic matter into methane (and its potential oxidation) perhaps generated in terrestrial ecosystems but transported into rivers (eg diffuse agricultural pollution) will allow for better policy and management / conservation eg protection of river riparian buffer zones / restoration of river habitat. |
Sectors | Agriculture, Food and Drink,Environment,Leisure Activities, including Sports, Recreation and Tourism |
Description | Findings have been presented to the key stakeholders involved with chalkstream ecosystems: the Environment Agency, the rivers trusts and angling societies that are concerned with the impact of agricultural diffuse pollution |
First Year Of Impact | 2016 |
Sector | Agriculture, Food and Drink,Environment,Leisure Activities, including Sports, Recreation and Tourism |
Impact Types | Cultural,Societal,Policy & public services |
Description | CASE contribution plus extra consumables to PhD studentship |
Amount | £12,000 (GBP) |
Organisation | Environment Agency |
Sector | Public |
Country | United Kingdom |
Start | 10/2013 |
End | 09/2017 |
Description | Fatty acid profiles |
Organisation | WasserCluster Lunz Biological Station GmbH |
Country | Austria |
Sector | Charity/Non Profit |
PI Contribution | Collection, sample prep and training for analysis of fatty acids diagnostic for methanotrophy |
Collaborator Contribution | Development of Fatty Acid profiling to bolster the identification and contribution assessment of methane-derived carbon to caddisfly larvae |
Impact | Too early |
Start Year | 2018 |
Description | Fatty acid profiling for methanotrophy |
Organisation | Queen Mary University of London |
Department | School of Biological and Chemical Science QMUL |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Formulation of ideas Collection of samples from Cumbria |
Collaborator Contribution | QMUL - RA to coordinate project and collect remainder of samples plus some sample prep Lunz - analytical services |
Impact | Too early |
Start Year | 2019 |
Description | Fatty acid profiling for methanotrophy |
Organisation | WasserCluster Lunz Biological Station GmbH |
Country | Austria |
Sector | Charity/Non Profit |
PI Contribution | Formulation of ideas Collection of samples from Cumbria |
Collaborator Contribution | QMUL - RA to coordinate project and collect remainder of samples plus some sample prep Lunz - analytical services |
Impact | Too early |
Start Year | 2019 |
Description | Jyv CH4 lakes |
Organisation | University of Jyvaskyla |
Country | Finland |
Sector | Academic/University |
PI Contribution | External evaluation and expertise on experimental design to manipulative study of top down control of methane fluxes |
Collaborator Contribution | Conducting whole lake experiment manipulating fish biomass |
Impact | Current submission of EoI to NERC for large grant |
Start Year | 2012 |
Description | MSc research project: climate change impacts on zooplankton use of chemosynthetic carbon |
Organisation | Freshwater Biological Association |
Country | United Kingdom |
Sector | Charity/Non Profit |
PI Contribution | Proposal of the original research topic Liaison between partners to establish access to data and archived samples Facilitation of fieldwork Training of student |
Collaborator Contribution | QMUL - provision of student and lab facilities including CF-IRMS CEH - access to long term data from lake monitoring, and samples of zooplankton FBA - access to archived zooplankton samples back to 1950s |
Impact | Too early |
Start Year | 2019 |
Description | MSc research project: climate change impacts on zooplankton use of chemosynthetic carbon |
Organisation | Queen Mary University of London |
Department | School of Biological and Chemical Science QMUL |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Proposal of the original research topic Liaison between partners to establish access to data and archived samples Facilitation of fieldwork Training of student |
Collaborator Contribution | QMUL - provision of student and lab facilities including CF-IRMS CEH - access to long term data from lake monitoring, and samples of zooplankton FBA - access to archived zooplankton samples back to 1950s |
Impact | Too early |
Start Year | 2019 |
Description | MSc research project: climate change impacts on zooplankton use of chemosynthetic carbon |
Organisation | UK Centre for Ecology & Hydrology |
Country | United Kingdom |
Sector | Public |
PI Contribution | Proposal of the original research topic Liaison between partners to establish access to data and archived samples Facilitation of fieldwork Training of student |
Collaborator Contribution | QMUL - provision of student and lab facilities including CF-IRMS CEH - access to long term data from lake monitoring, and samples of zooplankton FBA - access to archived zooplankton samples back to 1950s |
Impact | Too early |
Start Year | 2019 |
Description | Berlin Summer School on use of stable isotopes in ecology |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | 25 attendees on a week-long, residential summer school to share experiences and learn from expert tutors, bringing own data-sets for interrogation; increased uptake of use of stable isotopes in studies post workshop |
Year(s) Of Engagement Activity | 2016 |
Description | Gas, frass, and biomass in chalk streams |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Invited plenary presentation at the Chalkstream Headwaters Forum held annually at Sparsholt College, Hampshire and sponsored by Vitacress Prolonged question & answer session held to a panel of all speakers and incl local parliament representatives as well as from the water industry Invited again for 2014 |
Year(s) Of Engagement Activity | 2012 |
Description | Radio interview on greenhouse gas in lakes and climate change |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Media (as a channel to the public) |
Results and Impact | Interviewed by BBC at the Great Yorkshire Show regarding this research and related work on lakes |
Year(s) Of Engagement Activity | 2017 |
Description | Riverfly workshops |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | Riverfly Partnership Yorkshire meeting - outlined this novel research and how views are changing re fuelling of food webs. 50-60 people attended which sparked some debate after presentation. First meeting generated requests for two more. |
Year(s) Of Engagement Activity | 2017,2018 |