Silwood Park pond mesocosm
The impacts of warming on natural ecosystems remain poorly understood particularly for food webs and ecosystems where interactions add emergent properties that can only be understood using a system-level perspective. An array of artificial ponds (mesocosm) at Silwood Park is one the tools that will help to assess the impacts of warming across multiple levels of biological organisation, from genes to food webs and whole ecosystems. To characterise the impacts of warming on multispecies freshwater systems a recently NERC-funded project will integrate information generated from a network of experiments that include a global collection of naturally warmed and unwarmed freshwater habitats across a circumpolar ring of geothermal activity, hundreds of large-scale artificial streams and ponds (mesocosms) in the field, and thousands of robotically-assembled microbial communities in the laboratory (microcosms).
The pond mesocosm at Silwood Park is an array of 96 tanks where water temperature and concentration of major macronutrients (C, N, P) will be manipulated. Standardized measures of microbial community structure and functioning, the expression of key functional genes associated with C and N cycles, as well as records on biogeochemical cycling are some of the core data that will help understand the causal mechanisms of the effect of temperature and resource inputs at the base of the food web on higher trophic levels and ecosystem functioning in freshwater habitats. Silwood Park mesocosm will also provide material for seeding microcosm experiments where different microbial communities will be assembled and their functional attributes characterized across thermal gradients.
Silwood Park pond mesocosm is part of a NERC-funded grant awarded to Professor Guy Woodward, Dr. Thomas Bell, Dr. Alex J. Dumbrell, Professor Mark Trimmer and colleagues from Imperial College London, University of Essex, Queen Mary, University of London, and other institutions in the UK.
Mesocosm google map
details pond mesocosm
The Silwood Park mesocosm contains 96 1m3 tanks, a four-replicated experiment where each will receive one of 24 unique combination of temperature and nutrient treatments. Three water temperature treatments will include ambient control, plus +3.5 oC and +7.5 oC. Eight nutrient treatments will include the addition of C, N and P either alone or in all possible combinations. Each tank contains a layer of sand and gravel and is filled to the top with tap water.
The experiment started in March 2016 with the seeding of ponds using a combination of freshwater organisms from ponds and creeks in Silwood Park and neighbouring regions. Warming and addition of macronutrients is planned for spring 2017.
Planned core data includes:
- Metagenomic and metatranscriptome data from ponds to characterize the microbial community composition and gene expression with focus on genes related with C and N cycling.
- Rates of breakdown of leaf-litter and cellulose.
- Ecosystem respiration and primary production
- N2 fixation, N2 and N2O production, plus production and oxidation of methane
Find here the metadata file for this experiment (71KB)
Seeding of tanks with help of master's students, March 2016 (courtesy of Bruno Gallo)
Algal growth in mesocosms ponds by November 2016