set.seed(8)
degat <- data.frame(id = 1:4,
                    trt = sample(rep(c('controle', 'culture'), each = 2)),
         zooplancton.T1 = runif(4),
             poisson.T1 = runif(4),
         zooplancton.T2 = runif(4),
             poisson.T2 = runif(4))