The number of genera and diversity of nematodes were significantly higher in the open lagoons, followed by intermittent and were lowest at closed ones (Table 2 and Fig 3). Density was significantly higher in open lagoons and ICOLLs than in closed ones (Fig 3). Differences in the univariate measures between individual lagoons/lakes occurred mostly within the closed ones (S3 Table). Significant differences between outer and inner portions increased with lagoon connectivity. In the closed lagoons, the descriptors did not show any significant differences between inner and outer portions; in ICOLLs, nematode richness, diversity and density were, in general, higher in outer portion, or did not differ significantly (S4 Table). All descriptors differed significantly in open lagoons, where richness and diversity were higher in the outer portion and density was higher in the inner parts of the lagoons (Fig 3 and S4 Table).