ExMarine: An experimental field mesocosm system to study multiple-stressor impacts on rock pool biodiversity

Biodiversity loss due to increasing anthropogenic activities is one of the biggest threats to humanity. Understanding the impacts of multiple-stressors on ecosystems and biodiversity is therefore an urgent task. Shore ecosystems are especially valuable, as they harbour a high biodiversity and provide important ecosystems services. Until now, experimental approaches addressing multiple-stressor impacts on these ecosystems have been rare and mostly run with a limited number of replicates and under non-natural conditions. Here, an experimental field mesocosm system that allows studying multiple-stressor impacts on rock pool biodiversity is proposed. The ExMarine mesocosm system is composed of 64 experimental rock pool mesocosms in a fully randomised block design, which allows studying multiple-stressor impacts under highly standardised conditions. Water is taken directly from the sea, allowing biota to immigrate and emigrate freely. Water flow into the mesocosms can be regulated and it is possible to simulate disturbance through waves during high tide. The system can help to understand the impacts of multiple stressors on biodiversity, to monitor ecosystem health and to plan measures preventing the further loss of biodiversity.