Fifteen coastal lagoons/lakes (5 closed- Peri, Jaguaruna, Faxinal, Esteves, Cavera; 5 open—Camacho Laguna, Conceição, Barra Velha, São Francisco; 5 intermittent -Lagoinha do Leste, Garopaba, Ibiraquera, Urussanga, Sombrio) were sampled in the austral summer 2012. The lagoons are marginally urbanized, and sampling points have been selected out of the urbanization range to avoid potential influence of anthropogenic impacts. In each of the lagoons, 9 meiofauna samples and 3 of sediment samples (granulometry and total organic content) were taken in the outer and inner portions of the lagoons (a total of 18 samples of meiofauna and 6 samples of sediment per lagoon). The samples of each sample portion were taken dozens of meters apart from each other. For the closed lagoons, inner samples were those taken westward in the most interior region, while the outer samples were taken eastward near the sand barrier (exact location of sampling sites are available in S1 Table). Water salinity was measured in situ with a multiparameter YSI. Meiofaunal shallow subtidal samples (<1m depth) were taken with a plastic syringe of 2 cm in diameter pushed to a depth of 10 cm. They were immediately fixed in 4% formalin, later sieved through a 63 μm mesh and extracted by flotation with Ludox TM (specific gravity: 1.18). Samples were then evaporated with anhydrous glycerol and permanent slides were made . Sediment samples were taken with a PVC corer tube (10 cm Ø and 5 cm height). Granulometry was done by sieving and pipetting analysis and total organic content was determined by loss of ignition (550°C for 4 hours). Carbonate content of sediments samples was determined by acid digestion .