Warming is a major threat for organisms and has sharp consequences on benthic intertidal invertebrates due to their reduced mobility. Although they are exposed to daily temperature variations in temperate ecosystems, the effects of springtime warming on their functional traits are not well documented. The present study assessed the resilience of three marine invertebrates of the Wadden Sea to warming. Metabolic and phenological responses of <em>Mytilus edulis</em>, <em>Macoma balthica</em> and <em>Peringia</em> sp. were investigated under natural and warming scenarios in a mesocosms experiment. Benthic substrate and associated species were collected in the Wadden Sea and maintained in tanks in Sylt from March to June 2022. Three temperature treatments were applied: Ambient (i.e. field temperature), and elevated 1.5 and 3 degrees above ambient values. Respiration rates were measured to represent species’ metabolism while the physiological adjustments for the fitness were characterised by growth and body condition index. <em>Mytilus</em> and <em>Peringia</em> appeared to be highly resilient to warming, with a brief acclimation phase. They displayed an increased growth in warmer treatments without consequences for the condition. Conversely, <em>Macoma</em>’s growth was not stimulated by warming and individuals’ condition was negatively affected. These differences in species’ responses are expected to modify the structure of the coastal Wadden Sea ecosystem in the future, possibly increasing the vulnerability to additional stressors such as the introduction of invasive species.

Primary Presenter: Léa Joly, GEOMAR (jolyleasn@gmail.com)

Authors:

Léa Joly, GEOMAR  (ljoly@geomar.de)

Maysa Ito, GEOMAR  ()

Liam MacNeil, GEOMAR  ()

Maja Drakula,   ()

Anna Steinmann,   ()

Johannes Rick, AWI  ()

Knut Mehler, AWI  ()

Marco Scotti, GEOMAR  ()