Fig 1.
A. Study area (rectangle). B. Location of sample sites in transects with different colors offshore the Ria de Aveiro lagoon mouth. Legend: P. Cartola—Pontal da Cartola; P. Galega–Pontal da Galega; Fur–Furadouro; VR—Vouga River (adapted from Martins et al. [58]).
Fig 2.
Correlations between depth, sediment mean grain size (reported as grain size) and total organic matter (TOM).
Full line: significant correlation; broken line: non-significant correlation.
Fig 3.
Densities of assemblages in the investigated area.
A. Densities of living and dead individuals represented as pie charts. B. Dependence of densities from depth fitted by 6th order power functions. C. Dependence of densities from grain size fitted by 2nd order power functions (living) and linear regression. D. Dependence of densities from TOM fitted by 6th order (living) and 3rd order (dead) power functions. Full line: significant correlation; broken line: non-significant correlation.
Fig 4.
Similarities between assemblages’ density in the investigation area.
A. Similarities represented as circle areas. B. Dependence of similarities from depth fitted by 3rd order power function. C. Dependence of similarities from grain size fitted by 2nd order power function. D. Dependence of similarities from TOM fitted by 6th order power function. Full line: significant correlation.
Fig 5.
Rank distances between assemblages in the investigation area.
A. Rank distances represented as circle areas. B. Dependence of rank distances from depth fitted by 4th order power function. C. Dependence of rank distances from grain size fitted by 2nd order power function. D. Dependence of rank distances from TOM fitted by 3rd order power function. Full line: significant correlation.
Fig 6.
‘Incorporation Values’ of sites in the investigation area.
A. ‘Incorporation Values’ represented as circle areas. B. Dependence of ‘Incorporation Values’ from depth fitted by 6th order power function. C. Dependence of ‘Incorporation Values’ from grain size fitted by 2nd order power function. D. Dependence of ‘Incorporation Values’ from TOM fitted by 5th order power function. Full line: significant correlation.
Fig 7.
Similarity/Diversity index (SimDivers) of sites in the investigation area.
A. SimDivers represented as circle areas. B. Dependence of SimDivers from depth fitted by 5th order power function. C. Dependence of SimDivers from grain size fitted by 3rd order power function. D. Dependence of SimDivers from TOM fitted by 6th order power function; full line: significant correlation.
Fig 8.
Diversity diagrams of sample sites in the investigation area based on standardized species richness’ and heterogeneities.
Living assemblages in light blue, dead assemblages in orange. Species richness based on Chao1 [65] with = 43.84 and σ = 22.52; heterogeneity based on Evenness [66] with
= 0.573 and σ = 0.203. The blue circle indicates standardized means (
= 0) and standard deviations (σ = 1) for both species richness (abscissa) and heterogeneity (ordinate).
Fig 9.
Diversity diagrams of sample sites in Fig 8 arranged by transects and water depth.
Living assemblages in light blue and dead assemblages in orange.
Fig 10.
Diversity diagrams of sample sites positioned in a coordinate system obtained by nMDS.
Influence of environmental factors water depth, SMGS and TOM represented as vectors together with the variables standardized diversity vector’s length and angle. Living assemblages in light blue and dead assemblages in orange.
Fig 11.
Beta diversities along transects determined by Hill numbers 0D (species number) and 1D (dominant species).
A, B. Comparison between LAs and DAs of transect sites. C, D. Comparison between LAs of succeeding sites along transects. E, F. comparison between DAs of succeeding sites along transects. Grey lines: fit by logistic functions.
Fig 12.
Canonical correspondence analysis of the most abundant species based on depth distributions of living and dead individuals.
Groups are obtained by hierarchical cluster analysis Unweighted Pair Group Method with Arithmetic Mean using Cosine measures.
Fig 13.
Distribution maps of the main species density of living organisms: A. G. crassa rossensis (G. cras. rossens.); B. C. ungerianus. C. B. pseudoplicata; D. C. jeffreysii; E. P. mediterranensis. F. B. ordinaria. Legend: Cartola—Pontal da Cartola; Galega–Pontal da Galega; Fur–Furadouro; VR—Vouga River. Adapted from Martins et al. [58].
Fig 14.
Density (SD; n.°/50 ml) of dead individuals of C. laevigata/C. carinata and U. peregrina as a function of the depth.
Polynomial trend lines are presented.
Fig 15.
Depth frequencies of living and dead individuals for species of groups 1 and 2 according to UPGMA cluster analysis.
Groups are positioned in the CCA of Fig 12.
Fig 16.
Depth frequencies of living and dead individuals for species of groups 3 to 5 according to UPGMA cluster analysis.
Groups are positioned in the CCA of Fig 12.
Fig 17.
Depth frequencies of living and dead individuals for species of groups 6 to 8 according to UPGMA cluster analysis.
Groups are positioned in the CCA of Fig 12.
Table 1.
Distribution parameters for LAs and DAs of the most important species.
The means of normal-distributed components are arranged according to their height, thus designated as modes. Groups indicated by colors given in Fig 12.
Fig 18.
Daily upwelling index determined for Vigo (42°N, 9°W) for three months before and during the sampling events in: A. 1994 and; B. 1995. Legend: SE–sampling events of this work (reprinted from Martins et al. [58]).