Biotic and abiotic data European Benthic survey seagrass lucinids mutualism --- Give a brief summary of dataset contents, contextualized in experimental procedures and results. Data collection during benthic survey: Sampling was done in 14 Zostera noltii and 17 Zostera marina meadows across western Europe during the growing season (August – October) in 2018-2019. Lucinid bivalves and seagrasses were sampled with sediment cores (ø: 10-15 cm) to a depth of about 20 cm and then sieved over a 1-mm mesh. Data contains Loripes bivalve, seagrass and sediment characteristics ## Description of the data and file structure File1: Seagrass lucinid data locationID: location ID location: name of location species: seagrass species seagrass.totAB: total seagrass biomass (drymass, gram) znoltii.tot: total Z. noltii dry biomass (drymass, gram) zmarina.tot: total Z. marina dry biomass (drymass, gram) loripes.m2: density loripes m2 (numbers per m2) loripes01: presence absence loripes File2: sulfur data locationID: location ID location: name of location species: seagrass species deltaS: δ34S sulfur isotope (δ34S) %S: total sulfur procentage (% of sulfur) File3: Temperature and sediment locationID: location ID location: name of location mud: % mud sediment Tmin: annual average minimum temperature (Celsius degrees) Tmax: annual average maximum temperature (Celsius degrees) doc.warm: dissolved organic carbon warm water extraction (Carbon ppm) doc.koud: dissolved organic carbon cold water extraction (Carbon ppm) om: % organic matter sediment (% organic matter in sediment) Fe: sediment concentration of iron (Fe µmol/gram) S: sediment concentration of sulfur (S µmol/gram) species: seagrass species ## Sharing/Access information This is a section for linking to other ways to access the data, and for linking to sources the data is derived from, if any. Links to other publicly accessible locations of the data: email first author: j.defouw@science.ru.nl