Silwood Mesocosm Facility (SMF)

Silwood Park Campus, Imperial College London, Ascot, UK

Description of the infrastructure: The Silwood Mesocosms are 96 freshwater ponds, each 0.70 m deep and 1.85 m in diameter, identical to the mesocosms of the Iberian Pond Network (see above). The Silwood ponds were first filled with degassed tap water in summer 2015. Sand and gravel was added to 5 cm depth in October 2015. After this initial establishment phase, the ponds were seeded with organisms and propagules collected from local surface waters to establish standardised communities before starting experiments. The ponds are wide and shallow enough to mix naturally. Instrumentation will be installed in late 2016 in all experimental units to facilitate long-term high-frequency monitoring of temperature and oxygen. Less frequent monitoring of chlorophyll concentrations will be manual. Samples for eDNA and traditional analyses of benthic and planktonic organisms will be taken at the same time. Funding for these activities is secured through a NERC Large Grant (2015-2019), which will address impacts of warming and nutrients on community structure and ecosystem functioning in freshwater food webs. Experimental treatments in the mesocosms, which are part of this project, will be applied from late 2016 onwards. The mesocosm facility is complemented by a variety of facilities, including a microscopy lab, culture/live laboratory, constant temperature rooms (new rooms currently under construction and due for commission in 2017), several general-purpose labs and a -80°C freezer.